To investigate the effects of long-term fertilization on yield formation and its physiological regulation mechanisms in double cropping late rice,it utilized a long-term fertilization experiment(initiated in 1981)in red paddy soils of Jinxian.Four typical treatments were selected:no fertilization(CK),single application of nitrogen-phosphorus-potassium(NPK),double dose of NPK(HNPK),and combined organic-inorganic fertilization(NPKM).Comparisons were made on double cropping late rice yield,dry matter accumulation,chlorophyll dynamics,and differential gene expression in leaves at fullheading and filling stages in the 42nd year of long-term fertilization.Results showed that long-term fertilization resulted in yields ranked as NPKM>HNPK>NPK>CK,with HNPK and NPKM treatments significantly surpassing NPK,showing increases of 29.63% and 57.18% respectively.Compared with NPK,both NPKM and HNPK significantly improved yield components:effective panicles,grains per panicle,and grain density increased by 16.98%—46.42%,8.68%—15.26%,3.69%—7.37%,respectively.Regarding dry matter accumulation,NPKM and HNPK significantly enhanced dry matter weight at all growth stages and promoted translocation of stem-leaf dry matter to panicles from filling to maturity.The contents of chlorophyll in NPKM and HNPK treatments were significantly higher than those in CK and NPK treatments at all stages,and NPKM delayed the decay of chlorophyll from filling stage to maturity stage.Correlation analysis revealed significant positive relationships between yield and dry matter accumulation from tillering to heading(△DM1)and filling to maturity(△DM3),while showed extremely negative correlation with chlorophyll reduction from grain filling to maturity(△S3).Transcriptome analysis demonstrated that long-term fertilization significantly affected gene expression in leaves during fullheading and filling stages,with differentially expressed genes primarily enriched in photosynthesis,carbon/nitrogen metabolism,signal transduction,and stress-related pathways.In conclusion,long-term fertilization regulates gene expression and combined organic-inorganic fertilization improved yield components,enhanced early-stage dry matter accumulation,promoted assimilate translocation from vegetative organs to panicles during grain filling,maintain higher chlorophyll levels,and delayed leaf senescence post-grain filling.This comprehensive mechanism achieves yield enhancement through strengthening source(enhancing photosynthetic capacity),expanding sink(increasing dry matter storage),and facilitating flow(promoting assimilate transport).

To investigate the effects of optimizing basal-to-topdressing ratios combined with nitrogen application rates on nitrogen metabolism and nitrogen uptake/utilization in flue-cured tobacco,a field experiment was conducted using the cultivar Yueyan 97.Five treatments were designed:conventional basal-to-topdressing ratio (6∶4)+conventional nitrogen rate (CK),basal-to-topdressing ratio (4∶6)+conventional nitrogen rate (T1),basal-to-topdressing ratio (4∶6)+10% nitrogen reduction (T2),basal-to-topdressing ratio (4∶6)+20% nitrogen reduction (T3),and basal-to-topdressing ratio (4∶6)+30% nitrogen reduction (T4).It analyzed the impacts of these treatments on nitrogen metabolism,photosynthetic characteristics,dry matter accumulation,nitrogen uptake,nitrogen use efficiency,and nitrogen balance.The results showed that after optimizing the basal-to-topdressing ratio to 4∶6,the activities of key nitrogen metabolism enzymes,including glutamate dehydrogenase (GDH),aspartate transaminase (AST),and ferredoxin-glutamate synthase (Fd-GOGAT),were all higher than those under the traditional basal-to-topdressing ratio of 6∶4.When combined with nitrogen reduction treatments,the activities of nitrogen metabolism enzymes decreased.Specifically,T2 (10% nitrogen reduction) showed no significant difference from CK,while T3 and T4 (20%—30% nitrogen reduction) exhibited marked declines in enzyme activity.Optimizing the basal-to-topdressing ratio to 4∶6 also improved photosynthetic rate,SPAD values,dry matter accumulation,and nitrogen accumulation,with significant differences observed during the late growth stages.Furthermore,the optimizing 4∶6 ratio significantly enhanced nitrogen use efficiency.Compared to CK,nitrogen agronomic efficiency,partial factor productivity,recovery efficiency,and economic utilization efficiency increased by 20.68%,6.89%,4.06 percentage points,and 3.78 percentage points,respectively.Nitrogen reduction treatments reduced soil nitrogen surplus by 17.04—33.36 percentage points compared to CK.In conclusion,optimizing the basal-to-topdressing ratio from 6∶4 to 4∶6 in southern tobacco-growing regions enhances nitrogen metabolism during mid-to-late growth stages,improved photosynthetic performance,promotes dry matter and nitrogen accumulation,and increased nitrogen use efficiency.Coupled with 10% reduction in fertilizer can also reduce fertilizer input,mitigetes soil nitrogen surplus,and prevent environmental risks.

In order to explore the effect of straw interlayer on soil respiration and the chemical structural stability of organic carbon components during the remediation of saline-alkali soil,two experimental treatments were set up in the alfalfa-planting farmland at the Saline-Alkali Soil Improvement Experimental Demonstration Base in the Agricultural High-Tech Zone of Dongying City,Shandong Province:a straw interlayer treatment (S,with a 5 cm thick straw layer buried at a 35 cm depth) and a control (CK,without an interlayer). Soil respiration characteristics of the different treatments were analyzed,and comprehensive discussions were conducted in conjunction with soil pH,electrical conductivity(EC),organic carbon component content,and chemical structure characteristics of the soil profile.The results showed that:compared with CK,the S treatment significantly increased the soil respiration rate during the alfalfa growth period, with a maximum increase of 79.84%. Furthermore, the S treatment reduced soil EC in the straw interlayer (35—40 cm) and the overlying soil layer (0—35 cm), effectively inhibiting the upward migration of salt. The 40—50 cm soil layer was identified as a critical zone for organic carbon transformation. In this layer, the S treatment significantly increased SOC content (by 16.67%) and highly significantly elevated particulate organic carbon (POC) and dissolved organic carbon (DOC) contents (by 208.07% and 83.41%, respectively) compared with CK. Characterization of the molecular structure of organic carbon in the 40—50 cm layer revealed distinct responses. For DOC, the S treatment reduced the magnitude-weighted averages of unsaturation (by 30.60%) and aromaticity index (by 4.84%) compared with CK, decreasing the proportion of unstable carbon. For POC, the S treatment increased the relative abundances of alkyl C(10.32 percentage points)and O-alkyl C (8.39 percentage points) while reducing carboxyl C (14.24 percentage points), thereby enhancing POC structural stability. However, for bulk SOC, the S treatment decreased the proportions of alkyl C(3.14 percentage points) and aromatic C(3.38 percentage points) while increasing O-alkyl C(5.17 percentage points)and carboxyl C(1.56 percentage points). This shift indicated a decrease in recalcitrant carbon and an increase in labile carbon, resulting in reduced SOC structural stability. Correlation analysis showed that the significant increased in soil respiration was highly significantly and significantly positively correlated with POC and SOC contents in the critical soil layer, respectively. Specifically, the accumulation of O-alkyl C(a labile component) in the chemical structure of SOC reduced the stability of organic carbon,which was the main reason for the increase in soil respiration.In conclusion,incorporating a straw interlayer significantly increased soil respiration in the short term,which was closely related to the reduction in the stability of the organic carbon chemical structure in the key soil layer.Under future "carbon neutrality" strategies,research on the selection of interlayer materials should be considered.

To explore the relationship between soil bacterial community diversity and soil enzyme activity of Qinqiong(Q) and Magnum(M) under salinity stress treatment,the bacterial community structure and soil enzyme activity of Qinqiong and Magnum for 0,6,12,24,48 h were compared and analyzed by using high-throughput sequencing of bacterial 16S rRNA and colorimetry.The results indicated that at the phylum level,the relative abundances of Actinobacteria and Proteobacteria in the rhizosphere soil of Qinqiong were higher than those in Magnum.At the genus level,the relative abundances of Bacillus and Arthrobacter in the rhizosphere soil of Qinqiong were greater than those in Magnum,while the relative abundance of Pseudomonas was lower compared to Magnum.After 48 hours of saline-alkali stress,the activities of soil polyphenol oxidase(S-PPO),soil catalase(S-CAT),soil dehydrogenase(S-DHA),and soil invertase(S-AI) in the rhizosphere of Qinqiong were 1.32,1.53,1.38,and 1.28 times higher than those of Magnum,respectively.Furthermore,the S-CAT activity exhibited a significant positive correlation with the bacterial ACE and Chao diversity indices.Qinqiong may influence changes in bacterial community structure by altering the relative abundances of dominant bacterial groups,thereby enhancing the bacterial community diversity index and soil enzyme activity.In contrast,the changes in the bacterial community within the rhizosphere of Magnum were not significant.The diversity of soil microbial communities is a critical factor determining the saline-alkali tolerance of oat varieties.

In order to the issues of carbon-nitrogen balance and emission reduction in greenhouse soil,a field experiment was carried out to explore the impacts of the combination of summer catch sweet corn and biochar on nitrogen absorption and carbon emission reduction in greenhouse soil.Four treatments were designed for this experiment:control(T1),catch crop(T2),biochar(T3),atch crop+iochar(T4).The research results showed that the dry biomass and nitrogen absorption of T4 corn were 10.18% and 9.49% higher than those of T2,respectively.The organic carbon in the surface soil of T3 and T4 increased by 25.26% and 50.01% compared to before the experiment,respectively.The total nitrogen in the surface layer of T4 decreased by 10.13%,and the C/N increased to 14.9.The nitrate nitrogen in the 60—80 cm and 80—100 cm soil layers of T4 decreased by 13.02% and 5.68% compared to before the experiment,with a significantly greater reduction than other treatments.The non-root microbial biomass carbon and nitrogen of T4 increased by 26.00% and 20.33% compared to the control,with the increase in the non-root area being lower than that in the non-root area.The average CO₂ emission of T4 was 603.90 mg/m³,which was 24.61% lower than that of the control.In summary,the combination of fallow sweet corn and biochar significantly promoted nitrogen absorption,increased microbial biomass carbon and nitrogen,reduced carbon and nitrogen leaching and emissions,and improved soil C/N,providing theoretical basis support for carbon and nitrogen management in the summer fallow period of facility farmland.

To evaluate the effects of microbial inoculants on soil microbial population and physicochemical properties,this study investigated the effects of the microbial inoculants,including Bacillus velezensis BPC6(B), Streptomyces lydicus (S), and their combined inoculants(BS) on the soil microbial abundance and physicochemical properties of field-grown and potted peach trees in Pinggu District,Beijing.The results showed that applying microbial inoculants(B,BS,and S) significantly increased the abundance of bacteria,fungi,and actinomycetes in field soils.Additionally,the microbial inoculants enhanced soil nutrient utilization efficiency by increasing the contents of soil organic matter,total carbon,total nitrogen,available nitrogen(alkaline-hydrolysis nitrogen),nitrate nitrogen,ammonium nitrogen,available potassium,total phosphorus,and available phosphorus,while no significant effect was observed on total potassium.Among them,during the peach harvest period,application of microbial inoculants B,BS,and S significantly increased soil available nitrogen by 11.89%,15.19%,and 35.27%,respectively,compared to the control.Available potassium increased significantly by 35.58%,22.92%,and 41.75%,respectively,while available phosphorus rose significantly by 37.97%,3.65%,and 62.60%,respectively.Correlation analysis further revealed that soil microbial abundance was significantly influenced by multiple soil environmental factors,particularly showing a strong positive correlation with available potassium content.The effect of improving soil fertility with different microbial inoculants(B,BS,and S) was as follows:microbial inoculant S was the most effective,and the combination application of B and S was better than that of individual application of inoculant B.The pot experiment further confirmed the important role of microbial inoculants in increasing soil available nitrogen levels.Compared to the control,application of microbial agents B,BS,and S significantly increased soil available nitrogen in potted peach Zhongpan 100 by 15.65%,16.67% and 13.45%,respectively;while microbial agents BS and S significantly increased available nitrogen in Zhongtao 14 by 13.65% and 18.13%,respectively.Overall,microbial inoculants effectively improved soil microbial abundance and fertility,providing scientific support and practical references for sustainable peach production.

To fully utilize the effect of foliar fertilizer on increasing soybean yield,an experiment was conducted to study the effects of foliar fertilizer application frequency and timing on soybean growth,photosynthesis,yield and grain quality.The results showed that F1 (spraying at the beginning of flowering stage)was more beneficial than F2 (spraying at the beginning of pod stage)and F3(spraying at the beginning of filling stage)for increasing fresh leaf weight per plant,dry leaf weight per plant,fresh root weight,dry root weight,fresh root weight growth rate,dry root weight growth rate and dry matter accumulation rate of population,and spraying foliar fertilizer twice F4 (initial of flowering stage+initial of pod stage),F5 (initial of flowering stage+initial of filling stage),F6 (initial of pod stage+initial of filling stage)in improving the above indexes were better than spraying foliar fertilizer once F1,F2,and F3.Spraying foliar fertilizer once F2 was the most beneficial for increasing chlorophyll content and photosynthetic rate,while F1 had the highest canopy photosynthetically active radiation;spraying foliar fertilizer twice F4 had the highest values of chlorophyll content,photosynthetic rate and canopy photosynthetically active radiation,compared to F1,F2,and F3,F4 significantly increased chlorophyll content and canopy photosynthetically active radiation at filling stage by 8.22%,7.08%,9.89% and 9.25%,13.36%,16.78%,respectively.Compared to spraying foliar fertilizer once,spraying foliar fertilizer twice significantly increased the dry weight of soybean population,and compared to CK,spraying foliar fertilizer once and twice could enhance yield by 82.34—327.86 kg/ha and 318.91—463.98 kg/ha,respectively.Although spraying foliar fertilizer twice was more beneficial for increasing the protein content of soybean grain when compared to spraying foliar fertilizer once,the effect was insignificant,spraying foliar fertilizer at the initial of flowering stage+initial of pod stage was the most effective way to increase protein content.Overall,spraying foliar fertilizer once at the beginning of the flowering period was the most beneficial for improving soybean growth,photosynthetic characteristics and yield,while spraying at the beginning of the pod stage was the most beneficial for improving protein content,and spraying foliar fertilizer twice at the beginning of flowering stage+beginning of the pod stage had the best effect.

To address the challenges of water scarcity and excessive nitrogen fertilizer application in strong gluten wheat production in the low plain areas of Hebei Province,the effects of water-saving and nitrogen-reduction cultivation modes on grain yield and quality of strong-gluten wheat were studied and evaluated,which provided reference for breeding and cultivation management of strong gluten wheat in this region.Field experiments were conducted in Cangzhou from 2016 to 2018,with the conventional treatment(CK:irrigation of 1 500 m³/ha,nitrogen application of 240 kg/ha)as the control,two experimental groups were established:water-saving(W1:750 m³/ha;W0:0 m³/ha)and nitrogen-reduction(N-:120 kg/ha;N0:0 kg/ha).The yield and quality responses of 13 strong gluten wheat varieties were analyzed.The results showed that in the water-saving experiment,treatments W1 and W0 significantly reduced yield by 20.8% and 38.0%,respectively,compared with CK,while W0 exhibited a significant yield reduction of 21.6% compared with W1.The three tested varieties showed strong drought resistance and water-saving characteristics.Treatment W1 significantly prolonged the dough stability time by 8.25 min, while treatment W0 led to a significant decrease in protein content by 1.0 percentage point and a notable reduction in flour water absorption by 2.25 percentage points.Under reduced nitrogen treatment (N-), yield decreased by 3.7% compared to CK, but nitrogen absorption and utilization efficiency increased significantly by 9.8 percentage points.The treatment N0 showed a significant yield reduction of 15.8% and 12.6% compared to CK and N-, respectively. For dough quality, treatment N- increased the stability time by 0.6 min and the extensibility area by 0.35 cm², while treatment N0 caused a significant decrease in protein content by 0.8 percentage points and a reduction in other quality indicators.Principal component analysis showed that the treatment W1 achieved the highest comprehensive quality score(W1>CK>W0),among nitrogen reduction treatments,the ranking was CK>N->N0.Cultivars Shiluan 02-1,Gaoyou 5218,Gaoyou 5766,and Gaoyou 2018 demonstrated stable quality performance across all treatments,and can be used as excellent breeding materials.The conclusions showed that in the low plain areas of Hebei,moderate water stress(W1)could improve certain quality traits despite causing yield reduction;halving nitrogen application(N-)maintained stable yield while significantly improving nitrogen fertilizer absorption and utilization efficiency without affecting quality.The responses of strong gluten wheat to water and nitrogen regulation were asynchronous between yield and quality,and among different quality characteristics.Therefore,both breeding programs and cultivation management should adopt multi-objective synergistic optimization strategies to achieve balanced improvement in both yield and quality.

To investigate the partial substitution of earthworm manure for reduced fertilizer application in soybean cultivation,and to investigate the effects of different combinations of earthworm manure and fertilizer on soybean yield and quality,the suitable combination ratio of earthworm manure and fertilizer for soybean cultivation was selected through statistical analysis of soybean agronomic traits,yield traits,quality traits,and soil indicators.The results showed that compared with no fertilizer application,single application of earthworm manure,single application of chemical fertilizer,and different ratios of earthworm manure and chemical fertilizer can all promote the growth and nutrient absorption of soybeans.The promotional effect of T1 treatment was most significant.Compared with CK0(unfertilized),T1(80% fertilizer+25% earthworm manure)showed a significant increase in plant height,number of plant nodes,grain weight per plant,grain number per plant,hundred grains weight per plant,and pod number per plant.However,compared with CK1(100% fertilizer application),T1(80% fertilizer+25% earthworm manure)showed increases of 5.84%,3.23%,17.10%,13.48%,and 20.04% in plant height,number of plant nodes,grain weight per plant,ear number per plant,and pod number per plant,respectively.The yield of T1 and T4 treatments was significantly higher than that of CK0(unfertilized)treatment at the 0.01 and 0.05 levels.Compared with CK1(100% fertilizer),the yield increased by 9.89% and 22.67%,respectively.Compared with CK0(without fertilization),T1 and T4 treatments increased protein content by 2.59 and 3.31 percentage point,and total egg fat increased by 1.55 and 1.99 percentage point,respectively.Compared with CK1(100% fertilizer application),the protein content increased by 2.34,3.06 percentage point,and the total egg fat increased by 1.38,1.82 percentage point,respectively.The soil bulk density of T4(20% fertilizer+100% earthworm manure)was 0.90 g/cm³,which was the lowest value of the experimental treatment.The soil bulk density of T1 and T4 increased by 3.88% and 12.62% respectively compared to CK1(100% fertilizer).In summary,the combination of T1(80% fertilizer+25% earthworm manure)and T4(20% fertilizer+100% earthworm manure)has the most significant comprehensive improvement effect.Taking into account factors such as the cost of earthworm manure,it is recommended to choose a ratio of 180 kg/ha fertilizer(3∶1 for diammonium and urea)+5 625 kg/ha earthworm manure in soybean production.

In order to optimize the fertilizer application amount and proportion of high-quality grapes,the effects of different nitrogen(N),phosphorus(P),potassium(K),calcium(Ca)and magnesium(Mg)treatments on external quality index(including spike length,longitudinal diameter,transverse diameter,berry shape index,cluster weight and single grain weight),color indicators(including L^*,a^*,b^*,C,color index),internal quality indicators(including total soluble solid content,fruit firmness,titratable acid content,vitamin C)of Sunshine rose grapes were studied by L16(4⁵)incomplete orthogonal experimental design.The results of comprehensive fruit quality evaluation showed that T10 treatment had a strong effect on the improvement of transverse diameter,cluster weight,a^* and color index,and the cluster weight of T10 treatment was 844.3 g,which was significantly increased by 10.5%(T15)-55.8%(T4)compared with other treatments except of T11 and T12 treatments.T1 treatment had a strong effect on the increase of longitudinal diameter,and its longitudinal diameter is the largest(31.27 mm).T16 treatment had a strong effect on improving titrable acid content,vitamin C and fruit firmness,among which T16 treatment had the highest fruit firmness(4.93 N).Based on the comprehensive quality of fruits,the optimal theoretical formulation of N,P,K,Ca and Mg was N3P3K4Ca1Mg1,and the optimal dosage of N,P₂O₅,K₂O,CaO and MgO were 6.8,6.3,14.2,0,0 kg for producing 2 000 kg fruits,respectively.In production practice,the optimal fertilization scheme should be determined according to the soil fertility status.

Given the severe degradation of black soil in the semi-arid region of the western Songnen Plain and the inability to sow on time in some areas during spring, in order to clarify the mechanism of soil correlation during spring sowing and the growth and development of maize, clarify the adaptability rules for timely sowing of crops under different soil characteristics, strengthen the exploration and application of soil freeze-thaw cycles in the black soil area of Northeast China, and provide practical and effective theoretical basis and practical reference for timely spring sowing of crops in this climate zone. This experiment was based on the long-term positioning monitoring of soil quality at the Keshan Branch of Heilongjiang Academy of Agricultural Sciences. Under the conditions of freeze-thaw alternation in the medium thick black soil ecological zone, different terrain and landform soil water and heat conditions were monitored during the spring sowing period, and crop sowing adaptability evaluation was studied. Field experiments were conducted with different spring sowing period treatments: SD1 (April 15), SD2 (April 20), SD3 (April 25), SD4 (April 30), SD5 (May 5), and SD6(May 10) to monitor soil water and heat characteristics and analyze the growth, development, and yield formation of spring maize under different spring sowing treatments.As the spring sowing period was postponed,the external temperature gradually increased,accompanied by rainfall.The air humidity and soil temperature and humidity in the plow layer gradually increased,the soil bulk density decreased,the proportion of water stable aggregates decreased,and the proportion of small particle size soil particles showed an upward trend.Under different soil water and thermal conditions, the plant height, basal internode stem diameter, and root length of maize treated with the sowing date of SD5 during the tassel emergence stage to grain filling stage were significantly superior to those treated with other sowing dates; meanwhile, the SPAD value and leaf nitrogen content of maize leaves at different growth stages also showed better performance.In terms of maize ear traits and yield performance,SD4 treatment showed better performance in ear row number,ear shaft thickness,and seed depth;at the same time,the maximum yield was 13 545.23 kg/ha,which was significantly increased by 12.58% to 56.21% compared to the other treatments.Based on the actual ecological and climatic conditions of farmland in the middle thick black soil area in the northwest of the Songnen Plain,as well as the background of soil water and heat characteristics,timely early sowing of spring corn could make reasonable use of external light and water resources,promote plant growth and development,optimize plant dry matter accumulation,and achieve early and rapid harvest,thus achieving high and stable yield.

To investigate nitrogen and phosphorus accumulation and microbial community characteristics in ditch sediments, this study assessed a typical rice-rape rotation system. Sediment samples were collected from the ditches (concrete ditches and non-concrete ditches) during the dry season to analyze physicochemical properties and bacterial communities, in comparison to field soils.The results showed that the concentrations of total nitrogen(245.40 mg/kg),available phosphorus(25.03 mg/kg),pH(7.22)and electrical conductivity(586.28 μS/cm)in the sediments of concrete ditches were significantly higher than those in non-concrete ditches and field.The bacterial community structure in the sediment of non-concrete ditches was highly similar to that in the paddy field soil,while the α-diversity of bacteria in the sediment of concrete ditches was significantly lower than that in non-concrete ditches and paddy field.The dominant bacterial groups defined at the phylum level were similar in the ditch sediments and the paddy field soil,but the relative abundance of Proteobacteria,Cyanobacteria and Firmicutes in the sediment of concrete ditches was significantly higher than that in non-concrete ditches and paddy field.At the genus level,the sediment of concrete ditches had a higher abundance of norank_f_steroidobacteraceae compared to non-concrete ditches and paddy field.The sediment of concrete ditches had a lower abundance of functional groups of chemoheterotrophy and nitrogen fixation,but with a higher abundance of human pathogens and animal parasites or symbionts.The bacterial community composition and structure were primarily influenced by pH and nitrate nitrogen.These findings indicated that the sediment of concrete ditches had higher nitrogen and phosphorus contents,significant differences in bacterial community structure and function with lower bacterial richness and evenness.The concrete ditch,potentially acting as a source of nitrogen and phosphorus pollutants and posing certain health risks,should be given greater emphasis in the management of agricultural non-point source pollution.

Nitrous oxide(N₂O)is a long-lived greenhouse gas that is closely related to current global warming.With the development of agriculture,farmland soil has become a significant source of N₂O emissions,causing not only the loss of soil nitrogen but also serious environmental problems.The emission of N₂O from farmland soil has become a hot topic in the field of agriculture and environment.In order to better understand the mechanism of N₂O emission from farmland soil,the main biological pathways(biological nitrification,biological denitrification,denitrification by nitrifying bacteria,nitrate reduction to ammonium,fungal denitrification)and abiotic pathways of N₂O emission from farmland soil were discussed in this paper.The effects of endogenous driving factors(soil pH,temperature,moisture,iron form and content,organic carbon content and composition,carbon-nitrogen ratio and bulk density)and exogenous regulatory factors(nitrogen source input,biochar input and atmospheric CO₂ concentration)on farmland soil N₂O emission were reviewed.The relative importance of each pathway of N₂O emission and each influencing factor was clarified,in order to provide theoretical basis for the subsequent formulation of farmland soil N₂O emission reduction program.In addition,it was found that abiotic pathways contribute significantly to N₂O emissions under special conditions,such as flooding or when microbial activity is inhibited,and this pathway is regulated by soil pH value,metal ions(Fe,Mn)and organic matter.However,current studies mainly focus on biological pathways,and the reports on abiotic pathways and their influencing factors are scattered,lacking systematic understanding.Future studies need to pay more attention to abiotic pathways and their interactions with biological pathways in order to better understand the mechanism of soil N₂O emission in farmland and provide scientific guidance for sustainable agricultural development.

To clarify the alterations of rice straw decomposition,nutrients release and chemical components in coastal saline paddy soils under different nitrogen (N) application rate,for optimizing the technology of straw returning and realizing the efficient utilization of straw resources in coastal areas.The experimental site was located in Caofeidian District,Tangshan City,Hebei Province.The decomposition characteristics of rice straw and its lignocellulose,as well as the nutrient release characteristics of N,phosphorus (P) and potassium (K) were studied,using a 360-day straw-bag burying method with four different N fertilizer levels,including N0 (0 kg/ha),N1 (225 kg/ha),N2 (300 kg/ha) and N3 (375 kg/ha).Pyrolysis gas chromatography-mass spectrometry (Py-GC-MS) method was used to study the dynamic alterations of principal chemical components of the rice straw residues.The results showed that:the decomposition period of rice straw was divided into three stages,namely,rapid decomposition (0—30 d),slow decomposition (30—210 d) and slow decomposition (210—360 d),and the average decomposition rate of rice straw was 72.5% after 360 days with different N application rates.Increasing N application significantly increased the decomposition rate of rice straw.Compared with the N0 treatment,the N1,N2 and N3 treatments,increased the straw decomposition rate by 6.1, 7.4 and 9.2 percentage points,respectively.The trend of straw carbon (C) release rate was similar to that of straw decomposition rate,while the C release rate was only 43.2% at the end of the experiment.The nutrient release rates of rice straw were as follows:K>P>N.The N,P and K rapid release periods of rice straw was in the 0—30th (38.4%),0—60th (63.7%) and 0—15th (76.7%) days after straw decomposition,respectively.Both N and P of rice straw were enriched during the decomposition period.N application significantly increased the release of N from straw during the decomposition period,P in the early (0—15 d) and late (150—360 d) period,and K in the early period (0—15 d).Compared with the N0 treatment,the N1,N2,and N3 treatments,increased the straw N release by 6.6, 11.1, and 14.7 percentage points,P release by 2.2, 4.0, and 5.6 percentage points,and K release by 1.4, 2.1, and 2.8 percentage points,respectively.The lignocellulose decomposition rates of rice straw were as follows:hemicellulose>cellulose>lignin.Increasing N application significantly promoted the cellulose and hemicellulose decomposition rate of rice straw from day 0—90 and the lignin decomposition rate after day 90.Compared with the N0 treatment,the N1,N2,and N3 treatments,increased the cellulose decomposition rate of rice straw by 5.4, 7.3, and 8.4 percentage points, hemicellulose decomposition rate by 4.9, 6.4, and 7.4 percentage points,and lignin decomposition rate by 2.1, 5.1, and 5.7 percentage points, respectively.2-methoxy-4-vinylphenol,hydroxyacetone,2,3-dihydrobenzofuran,acetosyringone,eugenol,n-hexadecanoic acid,p-methylphenol,2,6-dimethoxyphenol,guaiacol,p-ethylphenol,and stigmasta-3,5-diene were the major (>1% relative) chemical components of straw residues during the decomposition period.Correlation analyses showed that straw decomposition rate,C release rate and cellulose,hemicellulose and lignin decomposition rates,were significantly positively correlated with eugenol,acetosyringone and 2,3-dihydrobenzofuran,while significantly negatively correlated with hydroxyacetone;straw P release rate was significantly positively correlated with hydroxyacetone and significantly negatively correlated with p-ethylphenol,eugenol and acetosyringone;straw K release rate was significantly correlated with p-ethylphenol,eugenol,acetosyringone and 2,3-dihydrobenzofuran,while significantly positively correlated with hydroxyacetone.In conclusion,increasing N application could promote the decomposition rates of rice straw and its lignocellulosic cellulose,and the nutrients release of straw N,P and K in coastal saline paddy field.The recommended optimal N application rate was 300 kg/ha under straw returning 10 500 kg/ha in coastal saline soils.p-ethylphenol,eugenol,acetosyringone,2,3-dihydrobenzofuran,hydroxyacetone,and stigmasta-3,5-diene could indicate the process of straw decomposition in straw residues.Py-GC-MS technique shows a good capability to monitor the chemical components alterations of straw residues,further deepening the understanding of straw decomposition mechanism.

To investigate the effects of climate warming and combined application of organic and inorganic fertilizer on soybean growth and yield,field experiments were conducted using infrared radiation warming systems to simulate temperature elevation.The experimental design included two temperature levels(T0:Ambient temperature;T1:Warming by 2.9 ℃)and two fertilization regimes(SF:Sole inorganic fertilizer;OF:Combined organic-inorganic fertilizer),aiming to examine the impacts of warming and fertilization practices on soybean dry matter accumulation,photosynthetic rate,leaf enzyme activities,and yield.Results demonstrated that compared to ambient temperature,warming shortened the pre-flowering and post-flowering growth periods by 3—4 d,5—6 d,respectively.Warming significantly reduced leaf nitrate reductase(NR)and glutamine synthetase(GS)activities during the pod-filling stage,decreased leaf area index(LAI)by 9.0%—13.7%,and suppressed net photosynthetic rate,collectively leading to 4.1%—19.3% reductions in post-flowering plant height and aboveground dry matter accumulation.In contrast,the combined organic-inorganic fertilization enhanced NR and GS activities,improved post-flowering photosynthetic efficiency,promoted plant growth,and increased the aboveground dry matter accumulation by 4.1%—15.3% compared to sole inorganic fertilization,with a significant interaction observed between NR and alanine aminotransferase activities.Yield analysis revealed that warming caused 9.7%—16.6%,13.3%—19.0% declines in pods per plant and grains per plant,respectively,resulting in 13.7%—21.1% yield reductions.Conversely,organic-inorganic fertilization increased grains per plant by 12.5% and pods per plant by 9.9%—10.5%,achieving 7.6%—10.8% yield improvements.Notably,significant positive correlations were detected among LAI,photosynthetic rate,nitrogen metabolism enzyme activities,and final yield.These findings demonstrate that climate warming inhibits post-flowering photosynthetic efficiency and aboveground growth in soybeans,while integrated organic-inorganic fertilization partially mitigates warming-induced yield losses through enhancing enzyme activities and photosynthetic performance,providing critical insights for adaptive agricultural practices under global warming scenarios.

In order to find out the way to achieve further improvement in the yield of sesame,a field experiment was conducted using the sesame variety Yuzhi ND837 with two treatments application of three-nutrient compound fertilizer (M1:675 kg/ha) and co-application of three-nutrient compound fertilizer with bio-organic fertilizer (M2:405 kg/ha three-nutrient compound fertilizer+4 500 kg/ha bio-organic fertilizer).The study investigated the effects of organic-chemical fertilizer co-application on the canopy photosynthetic characteristics,and yield formation across different vertical layers of sesame canopy.The results demonstrated that M2 significantly increased the leaf area index at all canopy levels,enhanced the photosynthetically active radiation interception rate (PARi) in the upper and middle layer while reducing the PARi of the lower leaves.The M2 significantly improved the photosynthetic rate,SPAD values,and photosynthetic potential at all canopy levels,thereby significantly increasing dry matter accumulation in each layer and overall. This resulted in increases of 10.99% and 7.55% in the number of capsules per plant in the upper and middle layers respectively;increases of 5.69% and 4.96% in thousand-grain weight;increases of 16.77% and 10.61%in grain yield;and a total yield increase of 289.42 kg/ha,representing 14.43% increase.In conclusion,compared to conventional chemical fertilizer,the co-application of organic-chemical fertilizer optimizes the photosynthetic capacity of sesame at different canopy layers,particularly in the upper canopy,thereby enhancing the overall canopy photosynthetic efficiency and ultimately resulting in higher yields.

In order to explore the effects of silicon fertilizer on lodging resistance,growth and development,yield,and quality of winter wheat,Kenmai 58 was used as the experimental material.The treatments included 15 kg/ha (Si1) and 30 kg/ha(Si2)silicon fertilizer applied as basal fertilizer,15 kg/ha (Si3) and 30 kg/ha(Si4) silicon fertilizer applied as topdressing at jointing stage,and no silicon fertilizer (CK).The stem lodging resistance at grain filling stage,plant growth,yield,and quality were measured.The results showed that Si4 significantly reduced the plant height,height of gravity center,and the length of the basal second internode.Compared with CK,Si3 increased the thickness of the basal second and third internodes by over 14.7%.Si2 and Si4 increased the plumpness and breaking resistance of the basal second or third internodes by 8.6%—18.7% and by 12.4%—49.2%,respectively.Nevertheless,silicon fertilizer had no effect on the diameter and dry weight of the basal internode.Moreover,silicon fertilizer increased the chlorophyll content (SPAD) of leaves at jointing stage,but had no effect on tillering,productive tiller percentage,dry matter accumulation,harvest index,yield,and main quality indexes.In summary,the application of silicon fertilizer improved the stem lodging resistance by lowering plant height,gravity center height,and basal internode length,while increasing the basal internode thickness,plumpness,and breaking resistance.Silicon fertilizer also increased chlorophyll content (SPAD) without adversely affecting wheat growth,grain yield,or quality.Silicon fertilizer could be applied either as basal fertilizer or topdressing at jointing stage.

In order to study the effects of different nitrogen application rates on rice yield,nitrogen uptake and soil fertility,the effects of different nitrogen application levels on rice yield,nitrogen use efficiency and soil tillage fertility in the Yellow River Irrigation Area were studied from 2021 to 2023 using rice variety Fuyuan 4 as the test material.Compared with other treatments,the average yield of 360 kg/ha was 9.4 t/ha,which was 182.94% higher than that of no nitrogen treatment,and 40.72% and 26.34% higher than that of 210,240 kg/ha.From the perspective of yield components,the increase in yield was mainly due to the increase of grain number per spike and the number of effective spikes,and excessive nitrogen application would cause the decrease of 1000-grain weight.The average of the 3-year results showed that the nitrogen use efficiency was up to 26.93% with 240 kg/ha of nitrogen,and the partial productivity of nitrogen fertilizer decreased with the increase of nitrogen application rate.The highest average value of organic matter was 18.60 g/kg after nitrogen application of 210 kg/ha.Compared with the non-nitrogen application treatment,the soil total nitrogen content of each nitrogen application treatment increased by 7.61%—15.67%,and the soil total nitrogen content of the 360 kg/ha nitrogen application treatment decreased with the increase of the experimental year.The total phosphorus content of soil was gradually reduced in the 360 kg/ha nitrogen application treatment,and the total phosphorus content in other nitrogen application treatments was maintained at about 0.85 g/kg.The total potassium content of nitrogen fertilization treatments gradually decreased with the increase of nitrogen application rate,and the total potassium content of the 360 kg/ha nitrogen application treatment decreased by 23.74%,22.16% and 8.85%,respectively,compared with the nitrogen fertilization treatments of 120,210 and 240 kg/ha.Soil available phosphorus increased with the years of the experiment,and the variation range between treatments increased with time.With the increase of nitrogen application rate,soil available phosphorus increased first and then decreased,and the soil available phosphorus of the 240 kg/ha treatment increased significantly in 2023 compared with other treatments.The soil available potassium of each treatment did not change significantly with the test years.By considering crop yield,nitrogen use efficiency and soil fertility,nitrogen application of 240 kg/ha could balance the environment and production requirements.

To investigate the effects of combined nitrogen and selenium fertilizer application on non-structural carbohydrates, yield, and quality of oil flax, this study utilized Longya 11 as the test material.A two-factor split-plot field experiment was conducted to examine the effects of nitrogen fertilizer(N0:0 kg/ha,N1:75 kg/ha,N2:150 kg/ha)and selenium fertilizer(Se:0 g/ha,Se1:30 g/ha,Se2:60 g/ha)on oil flax non-structural carbohydrates,grain yield and quality of oil flax under dryland conditions.The results showed that the content of soluble sugar of stems and leaves decreased gradually with the advancement of growth,while the content of starch of stems was the opposite.Under the same selenium fertilizer level,nitrogen fertilization significantly increased the soluble sugar and starch content of stems and leaves,dry matter accumulation,branch number,valid fruits,seed number grain,yield,and seed protein and oleic acid content,and the N2 level had the highest value,and the increase was greater at maturity stage.Under different nitrogen application levels,the combined application of N1 or N2 and selenium fertilizer significantly increased the soluble sugar and starch content of stems and leaves,the dry matter accumulation,branch number,valid fruits,seed number,1000-seed weight,grain yield,protein,oil content,lignans,and oleic acid content.Among the treatments,N2Se1 treatment significantly increased soluble sugar,starch content of stems and leaves and dry matter accumulation at maturity,and the valid fruits,seed number,and the 1000-grain weight were significantly higher than those of other treatments,which were 12.35%,3.89%,4.18% significantly higher than those of N2Se0 treatment,respectively.The oleic acid content of seed of N2Se1 was significantly higher than that of other treatments by 2.44%—25.64%,and the seed yield reached 1 700.50 kg/ha.The results showed that the combined application of 150 kg/ha nitrogen fertilizer and 30 g/ha selenium fertilizer could significantly increase the non-structural carbohydrate content and dry matter accumulation of oil flax stems and leaves in the test area,increase seed yield and oleic acid content,and improve quality.

In order to explore the effect of partial replacement of chemical fertilizer by organic fertilizer on the ecological stoichiometric characteristics of soil carbon,nitrogen and phosphorus in the Loess Plateau of Eastern Qinghai,a field experiment was conducted with continuous cropping of potato(Qingshu 9).This field experiment was established in 2022 with five treatments,i.e.no fertilizer(CK),100% chemical fertilizer(T1),30% organic fertilizer+70% chemical fertilizer(T2),50% organic fertilizer+50% chemical fertilizer(T3),and 70% organic fertilizer+30% chemical fertilizer(T4).Soil contents of organic carbon,total nitrogen,total phosphorus,alkali-hydrolyzable nitrogen,available phosphorus,microbial biomass carbon,nitrogen,phosphorus and soil-microbial biomass ecological stoichiometry were determined.The results showed that compared with 2022,the contents of soil organic carbon,total nitrogen,total phosphorus,alkali-hydrolyzable nitrogen,available phosphorus and microbial biomass carbon,nitrogen and phosphorus in each fertilization treatment in 2023 showed an increasing trend,while the CK treatment showed a decreasing trend.Among different soil layers,the content of each index gradually decreased with the increase of soil depth.Among different treatments,according to the content of each index,the order was T3>T4>T2>T1>CK.In the 0—30 cm soil layer,the contents of soil organic carbon,total nitrogen,total phosphorus,alkali-hydrolyzable nitrogen,available phosphorus and microbial biomass carbon,nitrogen and phosphorus under T3 treatment were 6.88%,17.65%,17.88%,84.71%,77.01%,65.67%,80.07%,54.91% higher than those of CK,respectively.The soil C∶N and C∶P in each soil layer were the highest in the CK treatment.Among the four fertilization treatments,soil C∶N,microbial biomass C∶N and C∶P were the lowest in the T3 treatment.In addition to the 0—10 cm soil layer in 2023,the soil C∶P in each soil layer was also the lowest in T3,while the microbial biomass N∶P in the T1 treatment was the lowest among all fertilization treatments.Soil C∶N and C∶P increased with soil depth.Correlation analysis showed that organic carbon,total nitrogen,total phosphorus,available nitrogen,available phosphorus and microbial biomass carbon,nitrogen and phosphorus were significantly positively correlated with each other.In summary,the substitution of organic fertilizer for chemical fertilizer can not only change the soil nutrient and soil microbial biomass content,but also change the soil ecological stoichiometry characteristics,and the treatment with 50% organic fertilizer+50% chemical fertilizer has the best effect.

Taking the safflower variety Yuhonghua No.1 as the research object,it adopted the planting method of two harvests of safflower and corn per year was adopted,and six fertilization treatments were set up:blank(T1),straw returning to the field(T2),straw+Bacillus subtilis bacterial fertilizer(T3(125 kg/ha),T4(250 kg/ha)),straw+Bacillus mucilaginosus bacterial fertilizer(T5(125 kg/ha),T6(250 kg/ha)).The influence of straw combined with bacterial fertilizer on the yield of safflower and soil nutrient availability was analyzed.The results showed that the continuous application of straw combined with bacterial fertilizer in 2023 and 2024 had a significant impact on the soil stoichiometric characteristics and yield.In terms of soil stoichiometric characteristics,the T5 treatment was the best for increasing total soil nitrogen(TN),the T3 treatment was the best for increasing total soil phosphorus(TP)and total soil potassium(TK),and the T4 treatment was the best for increasing soil organic matter(SOM).There were significant differences in soil N∶P,K∶P,and N∶K between two years,but the increase and decrease patterns were basically the same.The limiting factors for each treatment were all N and P elements.In terms of output,the T4 treatment was the best for increasing the filament yield,increasing by 62.53% and 52.99% respectively in two years.The T4 and T5 treatments had remarkable increasing effects on the output of seed yield.The output of T4 increased by 7.51% and 8.81% respectively in the two years,while that of T5 increased by 8.28% and 8.59%.There was an extremely significant positive correlation between soil TN,N∶P,N∶K,filament and seed yield,and there was a significant or extremely significant positive correlation between soil TN,SOM and filaments yield.Overall,among the two consecutive years of straw combined with microbial fertilizer application,the T3 treatment had the best effect in improving soil nitrogen,phosphorus,potassium and organic matter.The soils of each treatment were all limited by N and P elements.The T4 treatment had the most significant effect in increasing the comprehensive yield of filament and seed.

The effects of different nitrogen reduction and efficiency enhancement measures on ammonia volatilization and crop yield in fluvo-aquic soil of wheat-maize rotation system were studied to provide guidance for rational fertilization and agricultural environmental protection.A long-term nitrogen reduction was carried out since 2016 at the experimental station of Xuchang fluvo-aquic soil area in Henan Province.No nitrogen fertilizer control(CK),conventional nitrogen fertilizer(100N),20% nitrogen reduction(80N),and 20% nitrogen reduction combined with straw returning(80NS),nitrification inhibitor(80NI),and biochar(80NB)were set up.The soil physical and chemical properties,annual ammonia volatilization characteristics and wheat and maize yield of different treatments were studied from 2021 to 2022.In the wheat season,the pH value of 80NS,80NI and 80NB treatments was significantly higher than that of 100N treatment.The organic matter content significantly increased, while the soil bulk density significantly decreased in the 80NS and 80NB treatments, compared with the 80N and CK treatments, respectively. At the base fertilizer stage of wheat,the ammonia volatilization accumulation of 80NS,80NI and 80NB treatments was significantly lower than that of 100N by 28.71%,35.61% and 22.99%,respectively.During the topdressing stage of wheat season,the ammonia volatilization accumulation of 80NS and 80NB treatments was significantly lower than that of 100N by 14.94% and 17.58%,respectively.The ammonia volatilization accumulation of 80NS and 80NI treatments was significantly increased by 22.27% and 27.69% compared with 80N.During the whole growth period of wheat,the accumulation of ammonia volatilization in different nitrogen treatments accounted for 1.31%-2.47% of the nitrogen application rate,showing 100N> 80NB> 80NS> 80NI> 80N.In the maize season,compared with the accumulation of ammonia volatilization under 100N treatment,80N and 80NS treatments significantly decreased by 37.14% and 29.63%,respectively,and 80NI treatment significantly increased by 60.83%.Compared with 80N treatment,the accumulation of ammonia volatilization in 80NI and 80NB treatments increased significantly by 155.79% and 44.05%.The accumulation of ammonia volatilization in maize growth period accounted for 5.81%-14.86% of nitrogen application rate,showing 80NI> 100N> 80NB> 80NS> 80N.The wheat yield results indicated that compared with 100N treatment,80N treatment significantly reduced the yield by 16.67%,while 80NS,80NI and 80NB treatments did not significantly reduce the yield.Maize yield data showed that there was no significant difference between 100N treatment and four nitrogen reduction treatments.In summary,the application of nitrification inhibitors,straw and biochar on the basis of reducing nitrogen by 20% in the experimental fluvo-aquic soil can effectively improve soil fertility and stabilize crop yield.However,nitrification inhibitors and biochar significantly increase the accumulation of ammonia volatilization in maize season,which needs special attention in actual production.

To explore the effects of nitrogen application rate on nitrogen uptake and translocation characteristics,nitrogen use efficiency,and the formation mechanisms of yield and quality in soft wheat under weak light stress during the after anthesis stage,under pot conditions,the soft wheat variety Quanmai 725(QM725)was used as the material,and the ¹⁵N tracer method was used.Two nitrogen rates were set in the experiment,namely N1(N 120 kg/ha),N2(N 180 kg/ha),and two shading treatments were set at the wheat filling stage(7-35 d after anthesis)under each nitrogen application rate,namely CK(no shading),SH(30% shading).The relationship between nitrogen application rate and grain yield and quality of soft wheat under weak light after anthesis was analyzed,and the effects of different nitrogen application rates on nitrogen accumulation,transport,grain yield and quality of soft wheat under weak light after anthesis were studied.The results showed that compared with the control,under the conditions of N1 and N2,the nitrogen accumulation of plants at flowering stage and vegetative organs at maturity stage was significantly reduced by weak light treatment after anthesis,and the proportion of nitrogen from fertiliser was significantly higher than that from soil nitrogen,while the proportion of nitrogen accumulation in grains at maturity stage from soil nitrogen was significantly higher than that from fertiliser nitrogen.Under the same nitrogen application rate,the proportion of basal nitrogen fertiliser was greater than that of topdressing nitrogen fertiliser.Under the same weak light treatment conditions,compared with N1,N2 increased the accumulation of fertiliser nitrogen at flowering stage,the accumulation of total nitrogen and fertiliser nitrogen at maturity stage,and the accumulation of total nitrogen,fertiliser nitrogen and soil nitrogen at maturity stage.Under N1 and N2 treatments,the nitrogen harvest index,nitrogen harvest index,nitrogen production efficiency,grain number per spike,1000-grain weight and grain yield of wheat decreased significantly with the decrease of light intensity after anthesis.The content and accumulation of protein and starch in soft wheat grains increased significantly with the increase of nitrogen fertilizer.However,under the same nitrogen application rate,weak light stress reduced the starch content,protein and starch accumulation in grains.Weak light stress after anthesis significantly affected the nitrogen accumulation of soft wheat plants,reduced the transport efficiency of storage substances from vegetative organs to grains after anthesis,resulting in a decrease in the contribution rate of vegetative organs to grains,which was not conducive to the overall nitrogen transport efficiency of plants.With the increase of nitrogen application rate,the nitrogen harvest index,nitrogen harvest index,nitrogen production efficiency and nitrogen use efficiency of wheat were significantly improved.Under the same nitrogen application rate of N1 and N2,after anthesis weak light stress significantly reduced the accumulation of protein and starch in soft wheat grains,which in turn affected the formation of grain weight,resulting in a decrease in yield.

The effects of castor cake meal fertilizer on soil fertility and peanut yield and quality were studied.Using the peanut variety Silihong in Northeast China as the experimental material,a two-year field positioning experiment(2022 and 2023)was carried out,with no fertilization(CK),castor cake meal fertilizer(B1:2 520 kg/ha,B2:5 040 kg/ha,B3:10 080 kg/ha),chemical fertilizer(F1:175 kg/ha,F2:350 kg/ha,F3:700 kg/ha),cow manure(N1:3 724 kg/ha,N2:7 448 kg/ha,N3:14 896 kg/ha).A total of 10 treatments were used to analyze the effects on soil fertility and peanut yield and quality.The results showed that the application of castor cake meal fertilizer in 2022 and 2023 could improve soil nutrients to varying degrees.B3 treatment could significantly reduce soil pH value,and the effect of soil organic carbon,total nitrogen,total phosphorus,total potassium,alkali-hydrolyzed nitrogen,basic phosphorus,and available potassium content were the best.Compared with CK,the average increase was 67.58%,64.56%,70.55%,11.33%,75.76%,149.97% and 116.84%,respectively.Compared with CK,chemical fertilizer and cow manure made soil organic carbon,total phosphorus and basic phosphorus content increase by an average of 5.94% and 11.48%,16.67% and 16.67%,33.35% and 23.94%,respectively.The full fruit weight per plant,100 fruit weight,100 grains weight of peanut with B3 treatment were better than that treated with chemical fertilizer and cow manure,which increased by an average of 105.43%,127.91%,19.54% and 22.75%,16.79%,24.17%,respectively.B3 treatment had the highest peanut yield,which was 1 876.22 kg/ha higher in 2023 than 2022.B1 treatment increased the contents of peanut fat and oleic acid and decreased the content of linoleic acid and palmitic acid,compared with CK,the content of peanut fat and oleic acid increased by 6.07 and 4.23 percentage points,and the contents of linoleic acid and palmitic acid decreased by 1.79 and 0.89 percentage points.The contents of soil organic carbon,total nitrogen and alkali-hydrolyzed nitrogen were positively correlated with peanut fat content.The contents of soil organic carbon,total nitrogen and alkali-hydrolyzed nitrogen were significantly positively correlated with peanut yield.In conclusion,castor cake meal fertilizer could improve soil,increase peanut yield and quality.

To elucidate the distribution characteristics and evolution patterns of total nitrogen(TN)and hydrolytic nitrogen(HN)in irrigated desert soil profiles under long-term fertilization regimes,and to explore effective strategies for enhancing soil fertility and rational fertilization,it utilized soil samples(0-200 cm depth)collected in 2003 and 2022 from a long-term fertilization experiment established in 1982.TN and HN contents were measured across soil profiles,and their dynamic changes in the topsoil after 1,10,20,30,and 40 a of different fertilization treatments were analyzed.The results indicated that TN and HN contents gradually decreased with soil depth increasing under all fertilization regimes.Long-term combined application of organic manure and chemical fertilizers significantly increased TN content in surface soil.At the same time,treatments incorporating organic manure exhibited notably higher HN content in surface soil compared to those without organic inputs.Prolonged sole nitrogen fertilization led to TN profiles similar to those observed in unfertilized control plots.A significant positive correlation was identified between HN and TN across all fertilization regimes.Specifically,every 1.00 g/kg increase in TN under organic-amended treatments corresponded to a 71.57 mg/kg increase in HN.The findings demonstrate that long-term integrated organic-inorganic fertilization significantly enhances both TN and HN contents,thereby improving soil nitrogen fertility.Conversely,nitrogen depletion or excessive nitrogen-only applications reduced soil nitrogen fertility.These results highlight that combined organic and inorganic fertilization represents an effective approach for soil fertility improvement in irrigated desert soil regions.

The effects of tillage depth and organic fertilizer rates on photosynthetic characteristics,yield formation,and economic benefits of wheat were explored to provide a theoretical and technical basis for fluvo-aquic soil or similar soil types.The two-factor split-plot field experiment was conducted in the typical fluvo-aquic soil area of Qihe County,Dezhou City,Shandong Province from 2022 to 2024,where the tillage depth 15-20 cm(D1)and tillage depth 30-35 cm(D2)were assigned to the main plots,and the organic fertilizer rates of 800(L),1 200(M),and 1 600 kg/ha(H)were assigned to the subplots.The photosynthetic characteristics,aboveground dry matter accumulation characteristics and yield composition,in wheat were tested in fluvo-aquic soil under different tillage depths and organic fertilizer rates.Both D2M and D2H treatments were beneficial to improve the yield and yield components of wheat,and the spike number,kernels per spike,1000-grain weight,and grain yield significantly increased by 5.5%-8.5%,3.5%-12.1%,6.7%-13.2% and 6.6%-12.8%,compared with other treatments,respectively.D2M and D2H treatments also stabilized or increased the above-ground dry matter accumulation at jointing,anthesis,and maturity stages by improving the above-ground dry matter accumulation rate at each growth stage,which was 9.0%-22.1%,8.9%-25.8% and 10.7%-24.3% higher than averaged across the two years of other treatments,respectively.Compared with D1,D2 was more conducive to promoting the effect of organic fertilizer on the SPAD of leaves at different growth stages.Under D2M and D2H treatments,higher chlorophyll content could be maintained from the mid- to late-filling stages.Under M and H organic fertilizer application rates,the Pn of leaves at different growth stages of D2 was significantly higher than that of D1.At jointing,booting,flowering,mid-filling,and late-filling stages,on average over the two years,D2M and D2H increased significantly by 12.0% to 16.7%,13.7% to 16.8%,13.8% to 19.7%,20.2% to 25.8%,and 24.6% to 44.8%,respectively,compared with D1M and D1H.Under the same organic fertilizer application rates,the difference in leaf LAI between the two tillage depths gradually increased with the progression of the growth process.D2M and D2H performed best at anthesis and mid-filling stages,increasing by 13.2% to 27.2%,and 13.4% to 29.4%,respectively,compared with other treatments on average over the two years.In conclusion,both D2M and D2H treatments could enhance the photosynthetic characteristics of plants and the above-ground dry matter accumulation ability,thereby optimizing the yield components and achieving the drastically improvement of wheat yield.However,there were no significant differences in the indices between D2M and D2H treatments.Therefore,considering resource conservation,this study suggests that the combination of a tillage depth of 30-35 cm and an organic fertilizer application rate of 1 200 kg/ha can achieve wheat high yielding.

In order to explore the diurnal variation characteristics and influencing factors of surface CO₂ and N₂O emission fluxes in tobacco fields in central Henan under the management mode of continuous green manure incorporation,and to determine the optimal collection time of the two gases,in 2021,based on a long-term experiment in Maozhuang Science and Education Park of Henan Agricultural University,a 24-hour continuous dynamic observation was carried out by static dark box-gas chromatography every 30 days after tobacco seedlings were transplanted.The daily emission fluxes of CO₂ and N₂O in tobacco fields under nitrogen phosphorus potassium treatment(NPK)and NPK+planting and turning over ryegrass treatment(NPKG)were measured.The results showed that the tobacco field soil in central Henan was the source of CO₂ and N₂O emissions,and the emission trend was similar to the trajectory of atmospheric temperature change,which was high in day and low in night,and the average emission flux of day and night reached a significant difference level.The CO₂ emission flux showed an inconspicuous bimodal pattern at 30 and 60 days after transplanting,and a single peak state of high day and low night at 90 days after transplanting.The N₂O flux showed a single peak state of high day and low night.The CO₂ and N₂O emission fluxes of NPKG treatment were significantly higher than those of NPK treatment.The CO₂ emission fluxes of three typical days were 90 d>60 d>30 d,and the N₂O emission fluxes were 60 d>90 d>30 d.During the observation days,water-filled porosity of soil(WFPS) and 10 cm soil temperature jointly affected the emission rates of CO₂ and N₂O,and the 10 cm soil temperature was significantly or extremely significantly positively correlated with the daily emission fluxes of CO₂ and N₂O.The correction coefficients of daily CO₂ and N₂O emission fluxes at 9:00 and 21:00 were the closest to 1,and there was no significant difference compared with the daily average emission flux.There was a significant positive correlation between CO₂ flux and N₂O flux.Within a certain range,the N₂O flux increased linearly with the increase of CO₂ flux.In summary,continuous green manure returning increased the surface CO₂ and N₂O emission flux of tobacco field,and the best collection time of CO₂ and N₂O was around 9:00 and 21:00.During the three sampling days of tobacco growth period,the surface CO₂ emission flux of NPK treatment and NPKG treatment was the highest at 90 days after transplanting,followed by 60 days.The N₂O emission flux was the highest at 60 days after transplanting,followed by 90 days.

In order to investigate the effects of endophytic fungus Piriformospora indica on the rhizosphere microenvironment of tobacco,a pot experiment was conducted under greenhouse conditions,using Yunyan 87 as the experimental material to analyze its effects on tobacco root exudates,rhizosphere soil enzyme activities and bacterial diversity through non-targeted metabolomics,soil enzyme activity measurement,high-throughput sequencing,and microbial community functional prediction.The results showed that the P.indica successfully colonized in the roots of tobacco,increasing the content of 18 different root exudates,mainly including acids,esters,alcohols,terpenoids,and phenolic compounds,significantly enriching the metabolism pathways of L-phenylalanine,taurine and hypotaurine,and L-tryptophan.Compared to using sterile water as a control,P.indica increased the activities of urease,sucrase,and alkaline phosphatase in tobacco rhizosphere soil,with urease and sucrase activities reaching significant levels.P.indica increased the richness and diversity of bacterial communities in tobacco rhizosphere soil,with a significant increase in Chao1 index and Observed_otus index comparing with the control.This altered the bacterial community structure at the phylum and genus levels,and increased the relative abundance of dominant phyla of Acidobacteriota and Actinobacteriaota,as well as Pseudomonas and Gemmatimonas genera.It also increased the gene abundance involved in carbohydrate metabolism and translation pathways in rhizosphere soil bacteria,which had a certain impact on bacterial community function.It indicates that P.indica could improve the rhizosphere microecological environment of tobacco,providing a theoretical basis for understanding the mechanism of their promotion of tobacco growth and tobacco planting production.

In order to investigate the effects of different mulching measures on soil moisture and heat status and yield of winter wheat in northwest dry area,winter wheat Kangzhuang 974 was used as test material.From September 2022 to July 2023,three different coverage treatments including wheat straw strip covering three rows(M3),four rows(M4)and five rows(M5)and plastic film covering(PM)treatment were set up in the experimental base of Gansu Agricultural University,The open field(CK)was used as the control.The results showed that:compared with CK,the soil water storage of 0—200 cm during the whole growth period of winter wheat was significantly increased by mulch,the average increase of straw strip mulch was 13.22%,the increase range was M3>M4>M5,and the PM increased by 19.65%.The soil moisture increasing effect of mulch increased gradually with the progress of growth stage,and the maximum increase was 37.53—87.76 mm at maturity stage.It decreased with the deepening of soil layer,and the increase of 0—20 cm was the largest,ranging from 5.10—9.48 mm.Mulching significantly reduced the total water consumption and total water consumption intensity during the whole growth period,and the influence of mulching on water consumption and total water consumption intensity during the later growth period was most obvious.Compared with CK,wheat straw strip mulching significantly reduced the soil temperature of 0—25 cm during the whole growth period by 1.60—2.70 ℃,and M3 treatment had the largest decrease.The maximum decrease occurred at the grouting stage(3.67 ℃),and the maximum decrease between soil layers(3.01 ℃)occurred at 5 cm.Compared with CK,PM significantly increased the soil temperature from 0 to 25 cm during the whole growth period by 1.50 ℃,and the overwintering period and 5 cm had the largest increase,which were 2.20,1.79 ℃,respectively.The temperature of straw mulch increased at 7:00 at wintering stage,jointing stage and ripening stage,and the temperature increased and decreased at other times.PM temperature increased at all time except at 14:00 in grouting stage and ripening stage.Compared with CK, the yield and water use efficiency of M5 and PM were increased by 8.67%, 26.49% and 0.96, 2.94 kg/(ha·mm), panicle number was the most significant factor(CV=17.67%).Yield was significantly positively correlated with spike number(r=0.754^**),WUE(r=0.891^**)and soil temperature(r=0.723^**),and significantly positively correlated with grain number per spike(r=0.522^*).Banded mulching of wheat stalk can achieve both ecological and economic benefits,and M5 is more conducive to the formation of yield.

In order to study the effects of different fertilization treatments on the growth and development of aromatic rice,the present experiment was conducted with Qingxiangyou 19 xiang as the experimental material,and five fertilization treatments were designed,broadcasting compound fertilizer(T1),6 cm deep application of compound fertilizer(T2),broadcasting urea(T3),6 cm deep application of urea(T4),and no fertilizer applied treatment(T5),to explore the impacts of different fertilizer applications on the yield,quality,aroma,photosynthetic efficiency,and several other physiological properties of aromatic rice.The results of the experiment showed that the different fertilizer treatments had significant effects on the yield and quality of aromatic rice.The yields of aromatic rice were significantly higher in the deep-fertilization treatments(T2 and T4)than broadcasting-fertilization treatments(T1 and T3).In addition,the yield of aromatic rice was 19.61%,20.03%,39.57% and 32.28% higher than T5 treatment under T2 and T4 treatments in 2022 and 2023,respectively.In terms of net leaf photosynthetic rate,deep fertilization treatments significantly increased the net photosynthetic efficiency of aroma rice leaves by 25.69%,15.95%,17.83% and 11.28% under T2 and T4 treatments in 2022 and 2023,respectively,compared with T5 treatment.Moreover,2-acetyl-1-pyrroline(2-AP)content,2-AP synthesis-related precursor contents,and major enzyme activities were increased in aromatic rice under the deep fertilization treatments.Compared to the T5 treatment,the 2-AP content was significantly increased in the T2 treatments,reaching 161.31,180.17 μg/kg in 2022 and 2023,respectively.Furthermore,a significant increase in precursor content and major enzyme activities were also observed under deep fertilization treatments.The contents of proline,pyrrolidine-5-carboxylic acid and 1-pyrrolidine were increased by 9.90%,10.08%,4.38% and 8.13%,8.26%,6.06% under T2 treatment in 2022 and 2023,respectively.The activities of pyrrolidine-5-carboxylic acid synthetase and proline dehydrogenase activities were enhanced by 8.72%,27.79%,5.52% and 30.91% under the T2 treatment in 2022 and 2023,respectively.In conclusion,the deep fertilization treatment was able to significantly increase the yield,quality,net photosynthetic rate of leaves and promote the biosynthesis of 2-AP in aromatic rice.

Explore the effects of amino acid type water-soluble fertilizer on chlorophyll content and proportion of celery,and the regulation of gene expression related to chlorophyll metabolism,which provides a theoretical basis for the rational application of amino acid type water-soluble fertilizer foliar fertilizer in the production of high-quality pigment-rich celery.The celery variety Ningqin 1 was sprayed with different concentrations of amino acid type water-soluble fertilizer,the contents of chlorophyll a,chlorophyll b and total chlorophyll in leaf blades and petioles were determined and analyzed,and the relative expression levels of genes related to chlorophyll metabolism were determined by fluorescence quantitative PCR(RT-qPCR).The effects of amino acid type water-soluble fertilizer on chlorophyll accumulation and relative expression levels of related genes were related to the treatment concentration and leaf location.Treatment with 500 μL/L amino acid type water-soluble fertilizer increased the contents of chlorophyll a,chlorophyll b and total chlorophyll in leaf blades and petioles,and decreased the ratio of chlorophyll a/b in petioles.The expression of chlorophyll synthesis-related genes(AgHEMA,AgHEMB,AgCHLM,AgPOR and AgCAO)was induced,and the expression levels of degradation related genes(AgPAO and AgPPH)were significantly down-regulated.Treatment with 1 000 μL/L amino acid type water-soluble fertilizer inhibited chlorophyll accumulation to a certain extent,increased chlorophyll a/b ratio in leaf blades,and significantly down-regulated the expression levels of genes related to chlorophyll synthesis and chlorophyll degradation AgPPH.The suitable concentration of amino acid type water-soluble fertilizer foliar fertilizer can improve the chlorophyll content of celery at seeding stage by regulating the expression level of genes related to chlorophyll metabolism.

The aim was to elucidate the effects of different foliar fertilizer nitrogen application amounts on nitrogen accumulation,translocation,and utilization in maize.This experiment was conducted in 2021—2022 using a randomized block design,with maize variety Lihe 1 as the research object.No fertilization treatment (CK),conventional root fertilization treatment (CF),foliar nitrogen reduction treatment of 20% (LF1),foliar conventional nitrogen application treatment (LF2),and foliar nitrogen increase treatment of 20% (LF3) were set up to analyze the differences in nitrogen accumulation,translocation,and utilization of maize under different nitrogen fertilizer application amounts,no fertilization and conventional root fertilization.The results showed that the nitrogen accumulation in maize stems and leaves showed a trend of first increasing and then decreasing with the advancement of the growth stage,reaching the maximum value at the tasseling and silking stage.The nitrogen accumulation per plant gradually increased with the advancement of the growth stage and reached its maximum value at mature stage,the nitrogen accumulation per plant was highest in the LF2 treatment.The proportion of nitrogen distribution in leaves was highest before the silking stage;after the silking stage,the proportion of nitrogen distribution in grains gradually increased,reaching its peak at mature stage.The CK had the lowest proportion of nitrogen accumulation in grains,while the LF1 treatment had the highest proportion of nitrogen distribution in grains in 2021,and the LF3 treatment had the highest proportion of nitrogen distribution in grains in 2022.The nitrogen transport rate and the contribution rate of nitrogen transport to grains first increased and then decreased with the increase of nitrogen application amounts,the nitrogen harvest index and nitrogen utilization efficiency decreased with the increase of nitrogen application amounts;in 2021 and 2022,the nitrogen utilization efficiency of LF1 treatment,LF2 treatment,and LF3 treatment was higher than that of CF treatment,and the nitrogen utilization efficiency of LF1 treatment was the highest.The nitrogen absorption efficiency of foliar nitrogen application treatment for two years was higher than that of CF treatment.There were no significant differences in ear length,ear thickness,and ear row number among the treatments.CK had the longest bald tip length,and the row number and hundred grain weight of each nitrogen application treatment were higher than those of CK.CF treatment had the highest biological yield,while LF1 treatment had the highest grain yield and harvest index.The grain yield of each treatment was significantly higher than CK,and the harvest index decreased with increasing nitrogen application amounts.Therefore,maize can achieve better growth effects under LF1 foliar nitrogen application in the central and western regions of Inner Mongolia.

To clarify the effects of different tillage methods on soil moisture dynamics changes and maize yield under the condition of straw return to field in the black soil area along the foothills of Daxing'anling,based on six consecutive years of tillage positioning experiments,this study analyzed the effects of seven types of tillage methods,namely,full-crushing and deep-tillage (SCD),full-crushing and shallow-tillage (SSS),full-crushing and deep-tillage (SCS),full-crushing and re-harrowing (SCR),full-crushing and rotary tillage (STR),full-crushing and no-tillage (NTS),and conventional tillage without returning straw to the field (CK)on soil moisture characteristics,water consumption,water use efficiency,and agronomic traits and yield of maize in the 0—60 cm soil layer at different growth stages of maize in each treatment.The results showed a bimodal pattern of soil quality moisture content in 2022 and 2023.0—10 cm soil layer soil quality moisture content was significantly higher than that of CK,and the NTS treatment had the highest soil quality moisture content in several periods.10—20 cm soil layer soil quality moisture content was lower than that of CK in the SSS and NTS treatments at the jointing stage,and soil quality moisture content was higher than that of CK in the 20—40 cm and 40—60 cm soil layers in 2022 and 2023 for all the treatments.In 2022 and 2023,maize plant height in all treatments except NTS treatment was significantly higher than CK at different growth stages.The SCD treatment was the tallest and the NTS treatment was the shortest at mature stage.Leaf area index (LAI) varied little among treatments at seedling stage of maize,STR treatment had the highest LAI after the jointing stage,and all treatments had significantly higher LAI than NTS treatment at the big trumpet stage.Dry matter accumulation in all treatments except for the SCS,NTS treatment was significantly higher than in CK,and dry matter accumulation was highest in the SCD treatment and lowest in the NTS treatment at mature stage.All tillage treatments increased maize yield and water use efficiency compared with CK,but the SCD treatment was significantly higher than CK.Comprehensive analysis of the indexes showed that the two tillage methods of full-crushing and deep-tillage and full-crushing and shallow-tillage were favorable to improve soil structure,maize yield and water use efficiency in the black soil area along the foothills of Daxing'anling.

To provide theoretical basis and technical support for rational nitrogen fertilizer management in high-yield cultivation of hybrid wheat,this study aims to investigate the effects of nitrogen application rate on yield formation,dry matter accumulation and distribution,nitrogen absorption and utilization,as well as the nitrogen absorption ratio of wheat fertilizers in two-line hybrid wheat.From 2020 to 2021,three two-line hybrid wheat combinations and one conventional variety were used as materials.A split plot design was adopted,with nitrogen (labeled with ¹⁵N urea) treatment as the main zone and varieties as sub zones.Four nitrogen level experiments were set up at N0,N120,N180,and N240.The dry matter accumulation and distribution,plant nitrogen absorption and utilization,and grain yield of wheat organs were analyzed and measured under different treatments during the flowering and maturity stages.The results demonstrated that a highly significant effect of nitrogen application rate and combination (variety) on wheat yield and yield components.Compared with the conventional varieties Jingdong 17,the average yield of Jingmai 21 and BH9613 increased by 10.47% and 4.07% respectively,mainly due to their higher number of spikes and grains per ear.The application of nitrogen fertilizer significantly increased the number of spikes and grains per ear of wheat,but reduced the thousand grain weight.The application of nitrogen fertilizer to four varieties significantly increased the accumulation of dry matter in wheat during the flowering and maturity stages.The dry matter weight of various organs in wheat during the flowering stage was as follows:stem>leaf>spike,and during the maturity stage,it was as follows:grains>stem>spike-stalk+glume >leaf.The average values of nitrogen fertilizer agronomic utilization efficiency and nitrogen fertilizer partial productivity under different nitrogen application rates were as follows:Jingmai 21>BH9613>Jingdong 17>BH3606,which was consistent with the yield trend.The ¹⁵N atomic percentage of the four combinations (varieties),the nitrogen content from fertilizer,and the proportion of nitrogen from fertilizer all showed the following order:grains>straw,and they significantly increased with the increase of nitrogen application rate.Compared with Jingdong 17,the proportion of soil nitrogen in the three hybrid combinations (varieties) significantly increased,indicating that hybrid wheat had stronger tolerance to barrenness from the perspective of nitrogen utilization.After comprehensive consideration and analysis,the nitrogen application rate of N240 significantly increased wheat yield compared to other treatments,making it the optimal nitrogen fertilizer application rate for wheat cultivation.The comprehensive performance of the two hybrid combinations (varieties) of Jingmai 21 and BH9613 is better than the performance of the control Jingdong 17.

To investigate the effect of applying different gradients of nitrogen reduction on leaf production capacity of Korla fragrant pear,no fertilizer treatment(CK),no nitrogen fertilizer treatment(N0),conventional fertilizer treatment(N),and three nitrogen fertilizer reduction gradients(N1,N2 and N3,which reduced nitrogen use by 10%,20%and 30%,respectively,compared with conventional fertilizer)were set up in a total of six treatments.Leaf nutrient content,net photosynthetic rate,chlorophyll fluorescence,chlorophyll content,leaf area index and yield were compared under different fertilizer application methods based on multi-year fertilizer trials.Nitrogen fertilization significantly increased leaf and branch nutrient content,leaf chlorophyll content,leaf area index,net photosynthetic rate,chlorophyll fluorescence and yield,and soluble solids and VC content in fruit.Nitrogen reduction of 10% had no significant effect on leaf and branch nutrient content,chlorophyll fluorescence,net photosynthetic rate,chlorophyll content,leaf area index and fruit soluble solids,VC,stone cells and total acid content compared to complete N application,and N reduction of 10% to 20% had no significant effect on the orchard yield and was able to maintain it at the normal range level.Net photosynthetic rate,chlorophyll fluorescence parameters,and yield were significantly and positively correlated with N,P,K,Fe,Mn,Cu,and Zn contents in leaves and branches.According to the experimental results and analysis,the recommended range of nitrogen fertilizer reduction for Korla fragrant pear of 10—12 years old is 10%—20%(240—270 kg/ha)on the basis of fully applied nitrogen(300 kg/ha)as the optimal amount of nitrogen fertilizer reduction in fragrant pear orchards.

This study evaluates the efficacy of bio-organic fertilizer in managing Verticillium wilt in sunflowers,examining its effects on plant growth and disease resistance,and exploring its potential as a sustainable disease control strategy in sustainable agriculture.Pot experiment was conducted to investigate the effects of bio-organic fertilizer at different concentrations and under various treatment conditions on the sunflower Verticillium wilt pathogen and its impact on sunflower growth and disease resistance.The results indicated that the treatment significantly reduced the disease index of Verticillium wilt by 14.57% compared to the control group,with a relative control efficacy of 28.54% under indoor conditions.The application of bio-organic fertilizer significantly promoted sunflower growth and development.Specifically,when 1 g of bio-organic fertilizer was mixed with every 50 g of field soil,the sunflower emergence rate increased by 8.67 percentage point,and key physiological parameters,including seedling height,stem diameter,and fresh weight,were significantly enhanced.Further investigation revealed that bio-organic fertilizer fermentation filtrates at various concentrations effectively inhibited the growth of Verticillium dahliae colonies and spore germination,with inhibitory effects diminishing as dilution increased.Additionally,volatile compounds from the fertilizer significantly suppressed the formation of microsclerotia.In terms of disease resistance mechanisms,the bio-organic fertilizer fermentation filtrates enhanced plant resistance by inducing induced resistance.Physiological analysis showed that the filtrates triggered reactive oxygen species (H₂O₂)bursts,elevated the activities of superoxide dismutase (SOD) and peroxidase (POD),reduced malondialdehyde (MDA) accumulation,and increased the activity of phenylalanine ammonia-lyase (PAL),thereby significantly enhancing disease resistance in sunflowers.This study highlights the control potential of bio-organic fertilizer for managing sunflower Verticillium wilt and promoting plant health,providing theoretical and experimental support for optimizing fertilizer formulations and developing effective disease control strategies to enhance agricultural production.

Soil nitrogen(N)cycling enzyme activity serves as a crucial indicator for characterizing soil fertility and N transformation.To investigate the effects of long-term application of fertilizers on the soil enzyme activities correlated with N cycling in rhizosphere soil of double-cropping rice fields in southern China,our project was based on a continue 37-year fertilization localization field experiment,including four fertilization treatments:without fertilizer as a control(CK),single fertilizer(MF),rice straw residue and mineral fertilizer(RF),and 30% organic manure and 70% mineral fertilizer(OM).The activities of N cycling enzymes in the rhizosphere soil were measured,and their correlation with soil chemical properties was analyzed.The results were as follows:compared to MF and CK treatments,OM and RF treatments significantly increased the contents of total N(TN),organic carbon(SOC),ammonium N($\mathrm{NH}_{4}^{+}-\mathrm{N}$),nitrate N($\mathrm{NO}_{3}^{-}-\mathrm{N}$)and microbial biomass N(SMBN)in rhizosphere soil,and also increased rice yield.The urease(Ure)and nitrite reductase(NiR)activities of rhizosphere soil in OM and RF treatments were significantly higher than those in MF and CK treatments.The RF treatment significantly increased rhizosphere soil hydroxylamine reductase(HyR)activities compared to the other three treatments,by 21.7%,13.0%,and 8.7%,respectively.This finding shown that OM treatment significantly increased protease(Pro),nitrogenase(Nit),nitrate reductase(NR)and nitrous oxide reductase(Nos)in rhizosphere soil compared to RF,MF and CK treatments.In comparison to MF treatment,OM treatments increased Pro,Nit,NR and Nos activities in rhizosphere soil by 20.0%,26.1%,426.1% and 26.7%,respectively.Nonetheless,the activity of nitric oxide reductase(Nor)on rhizosphere soil was considerably higher in the CK treatment than in MF,RF and OM treatments.Pearson correlation analysis revealed a substantial positive correlation between soil NR,NiR,Nit,Nos,Ure,Pro and soil TN,SOC,$\mathrm{NH}_{4}^{+}-\mathrm{N}$,$\mathrm{NO}_{3}^{-}-\mathrm{N}$,SMBN as well as rice yield.Soil Nor activity was observed to have a significantly negative connection with soil TN,SOC,$\mathrm{NH}_{4}^{+}-\mathrm{N}$,$\mathrm{NO}_{3}^{-}-\mathrm{N}$,SMBN and rice yield.The findings presented above showed that soil chemical properties and yield were substantially related to rhizosphere soil N cycling enzyme activities.Redundancy analysis(RDA)showed that the first order axis could explain 93.34% of the enzyme activity in rhizosphere soil and soil $\mathrm{NO}_{3}^{-}-\mathrm{N}$,TN and SOC contents were the key factors affecting the pattern of rhizosphere soil enzyme activities.Therefore,the long-term application of organic materials such as organic manure and rice straw can enhance soil chemical and biological characteristics,stimulate soil N cycling enzyme activities,and effectively fertilize paddy soils by partially replacing chemical fertilizers.

In order to provide production advice of high-quality upper tobacco leaves,field experiment was carried out to elucidate the effects of nitrogen application on the growth,development,carbon and nitrogen metabolism of upper leaves of different tobacco varieties.Three treatments,37.5(LN),75.0(MN)and 112.5 kg/ha nitrogen application rate(HN)were conducted with NC89 and Yunyan 87 as the test varieties.The effects of different treatments on the agronomic traits,photosynthetic characteristics,leaf tissue structure,key enzymes activity of carbon and nitrogen metabolism,and chemical composition of the upper leaves of were studied.The results showed that the leaf length,leaf width,leaf area,and leaf dry mass of the upper leaves of both varieties were significantly improved with the increased of nitrogen application rates.At 115 days after transplanting(DAT),the leaf area of NC89 and Yunyan 87 of HN were significantly increased by 63.10% and 68.43% compared to LN,respectively.Increasing nitrogen rate improved the leaf chlorophyll content of NC89,the leaf chlorophyll content of HN was 6.67%—37.50% higher than that of LN,respectively.The leaf net photosynthetic rate was notably improved by increasing nitrogen rate of Yunyan 87,especially at 70 DAT and 80 DAT.The leaf palisade tissue,leaf spongy tissue,and leaf thickness were markedly promoted with the increased nitrogen application rate on 85—115 DAT.The palisade tissue and spongy tissue thickness of LN and MN were almost stable from 95 to 115 DAT,but HN improved by 9.82%—14.08% and 10.72%—13.72% respectively.The leaf carbon content and leaf carbon and nitrogen ratio of both varieties were significantly decreased by reduced nitrogen rate,while leaf nitrogen content significantly increased.The activities of invertase,sucrose phosphate synthase,sucrose synthase,and glutamate synthase of both varieties were increased with the increased nitrogen application rate.HN decreased the amylase activity of Yunyan 87,but increased that of NC89.At 115 DAT,the amylase activity of HN of Yunyan 87 was 27.53% lower than MN,while HN increased amylase activity by 33.86% and 21.74% compared to LN and MN of NC89,respectively.The activity of glutamine synthetase of Yunyan 87 significantly increased with the increased nitrogen application rate,while there was no significant difference among different treatments of NC89.The content of flue-cured tobacco leaf reducing sugar and total sugar were reduced,but the content of nicotine and total nitrogen were improved with increased nitrogen application rate.Under the same nitrogen application rate,the content of flue-cured tobacco leaf nicotine,total nitrogen,and potassium of Yunyan 87 were higher than NC89,while the content of reducing sugar,content of total sugar(except LN),sugar and nicotine ratio,and nitrogen and nicotine ratio were lower than NC89.The effect of nitrogen application rate on upper leaves of tobacco varieties is difference.Increasing nitrogen application rate could promote the growth,development and carbon metabolism,reduce sugar and nicotine ratio and nitrogen and nicotine ratio,and improve the coordination of chemical components of NC89.However,increasing nitrogen application rate could lead to excessive nitrogen metabolism,delay the transformation from nitrogen metabolism to carbon accumulation metabolism,and cause late maturity of Yunyan 87.

To clarify the regulatory effect of nitrogen(N)fertilizer reduction and postponing on the productivity of wheat-maize double cropping system in Huang-Huai-Hai Plain.The annual N fertilizer experiment of summer maize and winter wheat was established of four N application systems:annual N fertilizer application 400 kg/ha of traditional farmer treatment(F₄₀₀),10% reduction of annual N fertilizer(FN),20% reduction of annual N fertilizer(FH),and 30% reduction of annual N fertilizer(FL)from 2020 to 2023 at Jiyang Experimental Base of the Shandong Academy of Agricultural Sciences in Jinan.The grain yield,aboveground N accumulation characteristics,N use efficiency,and the nitrate residue after harvest in the 0—200 cm soil layer of wheat-maize double cropping system were tested,in order to provide the theoretical basis for further optimization of N fertilizer management in Huang-Huai-Hai Plain.The results indicated that N fertilizer postponing was optimized the grain yield of summer maize and winter wheat under the condition of N reduction,and the averaged across the three years,FL significantly increased by 9.2%—18.1%,13.5%—20.5%,and 11.1%—19.1%,respectively,compared with F₄₀₀ and FN.N fertilizer postponing improved the N accumulation rate,and promoted aboveground N accumulation at wheat-maize different growth stages,and the averaged across the three years,FL significantly increased plant N accumulation by 5.7%—12.3% and 5.0%—12.8% under silking and maturity,respectively,compared with F₄₀₀,FN,and FH,as well as 8.2%—17.2% in grain N accumulation.For winter wheat,FL and FH treatments were significantly higher than F₄₀₀ and FN at jointing,anthesis,and maturity,and the averaged across the three years,FL and FH significantly increased by 23.4%—28.1%,20.7%—26.3%,and 12.6%—20.8%,respectively,compared with F₄₀₀,FN and FH,at the same time the grain N accumulation under FL significantly increased by 16.4%,15.0% and 5.8%,respectively,compared with F₄₀₀ and FN.N fertilizer postponing optimized the N use efficiency of wheat-maize double crop system,the averaged across the three years,FL significantly increased N uptake efficiency by 4.8%—57.7% and 32.0%—72.4% of summer maize and winter wheat,respectively,compared with F₄₀₀,FN,and FH;and FL significantly increased N partial factor productivity by 68.8% and 40.4% in summer maize,respectively,compared with F₄₀₀ and FN,as well as by 38.4%—71.8% in winter wheat compared with F₄₀₀,FN,and FH.At harvest of summer maize and winter wheat,the soil nitrate residue was mainly enrichment in the 0—40 cm soil layer under four N application systems,the averaged across the three years,accounted for 40.0%,38.9%,44.9%,42.5% and 37.3%,36.9%,46.7%,38.3% of the 0—200 cm soil layer,respectively.In addition,the obvious accumulated effects in 0—200 cm soil layer nitrate residue under F₄₀₀ and FN treatments at harvest of summer maize and winter wheat,but there was the relative balance was achieved under FL and FH treatments.In conclusion,a 30% reduction of annual N fertilizer by N fertilizer postponing could optimize plant N accumulation characteristics and realized synergistic improve grain yield and N use efficiency.Therefore,FL treatment was an optimal N application system for realizing the collaborative target of high-yield,high-efficiency,and environment-friendly of wheat-maize double cropping system in Huang-Huai-Hai Plain.

To explore the impact of organic fertilizer on the physiological growth of flax and the rhizosphere bacterial communities,and to investigate green high-yield cultivation techniques for flax in dryland,a field experiment was conducted using Baxuan No.3 as the material.The study examined the effects of four different fertilization treatments(T0:no application; T1:low quantity of cow manure; T2:medium cow manure; T3:high quantity of cow manure)on the physiological growth changes,nitrogen utilization,dry matter accumulation,and the diversity,community composition,co-occurrence networks,and metabolic pathways of the rhizosphere bacteria of flax,as well as discussing the environmental factors driving the differences in bacterial communities.The results showed that the T3 treatment resulted in higher flax production. Compared to the control, this fertilization condition also had the highest indicators for plant height, capsule fruit number per plant, thousand-grain weight, and nitrogen use efficiency, which form the physiological basis for stable yield following the application of organic fertilizer.The application of organic fertilizer significantly affected the diversity and richness of the rhizosphere soil bacteria of flax,and there were significant differences in the structure of the rhizosphere bacterial community.The population structure of the rhizosphere bacteria of flax was influenced by organic matter,total nitrogen,and available phosphorus.The dominant flora in the rhizosphere of flax was the same across different treatments,but the relative abundance of each dominant flora varied significantly.The rhizosphere of flax was dominated by the phyla Proteobacteria,Actinobacteria,Acidobacteria,Chloroflexi,and Bacteroidetes.The relative abundance of Proteobacteria and Actinobacteria increased with the increase of organic fertilizer treatments,while that of Acidobacteria decreased with the increase of organic fertilizer treatments.WGCNA analysis identified 15 co-expression modules,with the Red and Pink modules showing a significant positive correlation with organic matter content.The application of organic fertilizer increased the complexity of the bacterial network,and seven key OTUs were identified through combined WGCNA analysis.In conclusion,the application of organic fertilizer promoted the growth of flax and altered the structure and network complexity of the bacterial community in the rhizosphere soil of flax.

In order to explore a good fertilization model to improve the fertility of yellow-cinnamon soil in Southern Henan,the characteristics of stable and high yield of wheat-maize rotation system and its relationship with soil nutrients under different fertilization treatments on yellow-cinnamon soil were studied.Based on the long-term experiment since 2012,four treatments were set up:no fertilizer(CK),chemical fertilizer(NPK),chemical fertilizer combined with manure(NPKM)and chemical fertilizer combined with straw(NPKS).Plants and soil samples were collected at maturity stage to determine crop yield and soil organic carbon,alkaline nitrogen,available phosphorus and available potassium.The results showed that compared with CK treatment,the crop yield of each fertilization treatment was significantly increased,the yield of wheat was increased by 53.70%—64.50%,and the yield of maize was increased by 44.54%—58.31%.The yield of NPKM treatment was the highest(wheat 8 162.61 kg/ha,maize 8 836.33 kg/ha),and there was no significant difference between NPKS and NPKM treatments.The yield sustainability index(SYI)of NPKM treatment was the highest,and the SYI values of wheat season and maize season were 0.84 and 0.82,respectively.The crop yield and its SYI value both showed NPKM>NPKS>NPK>CK,indicating that chemical fertilizer combined with organic materials could significantly increase crop yield and its sustainability.At the same time,different fertilization treatments could improve soil nutrients to varying degrees,among which NPKM treatment had the most significant improvement effect.The relationship between crop yield and soil nutrients was analyzed.The relationship between crop yield and soil nutrients was analyzed.There was significantly positive correlation between crop yield and soil organic carbon(SOC),available nitrogen and available phosphorus contents,among which the correlation between crop yield and SOC was the most significant.With the increase of soil organic carbon content,the SYI value of crops increased first and then stabilized,and the inflection point was 15.15 g/kg.To sum up,the application of chemical fertilizer combined with manure can significantly increase crop yield and soil nutrients,and maintain high crop yield sustainability.It is a recommended fertilization model to achieve sustainable production of soil-crop system in yellow-cinnamon soil ecological zone.

The aim was to clarify the effects of different nitrogen application levels on soil organic nitrogen fractions and nitrogen use efficiency in maize fields in the central-western region of Inner Mongolia,so as to provide a reference for the scientific management of soil nitrogen and sustainable development of modern agriculture.Six nitrogen application levels were set up,N0(0 kg/ha),N8(120 kg/ha),N12(180 kg/ha),N16(240 kg/ha),N20(300 kg/ha),and N24(360 kg/ha).The dynamic changes with effects of nitrogen application on soil total nitrogen content,particulate organic nitrogen content,light fraction organic nitrogen content and heavy organic nitrogen content,as well as maize yield and nitrogen use efficiency were analyzed at different soil layers at pre-sowing and post-harvest.The results showed that soil total nitrogen,particulate organic nitrogen,light fraction organic nitrogen,and heavy fraction organic nitrogen content decreased with deepening of the soil layer at the same nitrogen application level;soil total nitrogen content at pre-sowing increased with the nitrogen application levels.Soil total nitrogen content in the N16,N20,and N24 treatments was significantly higher than that in the N0,N8,and N12 treatments at post-harvest.Soil particulate organic nitrogen content of N16 treatment was highest in the 0—10 cm,10—20 cm,and 20—40 cm soil layers at pre-sowing,with 0.14,0.13,and 0.09 g/kg,respectively.At post-harvest,N16 treatment had the highest content in the 10—20 cm,20—40 cm,and 40—60 cm soil layers,with 0.19,0.10,and 0.09 g/kg,respectively.The highest increase of soil light fraction organic nitrogen content of 37.27% was in the N16 treatment,and the highest increase of soil heavy fraction organic nitrogen content of 7.35% was in the N24 treatment,followed by the N16 treatment,at 6.84%.The N16 treatment had the highest maize biological yield of 31 443.50 kg/ha;the highest maize economic yield of 18 526.47 kg/ha;and the nitrogen use efficiency decreased with the increase in nitrogen fertilizer application levels,N16 treatment in the nitrogen harvest index was the highest, at 79.20%.In conclusion,the more suitable nitrogen fertilizer application level in the central-western region of Inner Mongolia should be maintained under 240 kg/ha,in order to achieve the best soil nitrogen management ang crop yield.

In order to investigate the effects of reactive oxygen species(ROS)on the growth and antioxidant system of sweetpotato under potassium deficiency stress,and further reveal the defense mechanism of ROS regulation in sweetpotato under potassium deficiency stress.This study selected two sweetpotato varieties,Xushu32(low potassium tolerant)and Ningzi 1(low potassium sensitive),as experimental materials.The experiment was conducted in an artificial climate chamber using hydroponic cultivation to ensure consistent environmental conditions.After pretreatment with exogenous H₂O₂ and diphenyl chloroiodate(DPI),ROS inhibitor,the sweetpotato seedlings were subjected to potassium deficiency treatment.The changes in relative H₂O₂ content,antioxidant gene expression levels,and enzyme activity indicators in sweetpotato roots at different time points after potassium deficiency treatment were measured.The morphological characteristics of sweetpotato were recorded to explore the effects of ROS signaling on the growth of sweetpotato seedlings under potassium deficiency stress.The results showed that under potassium deficiency treatment,the biomass of sweetpotato decreased and leaf color lightened.The relative concentration of ROS in sweetpotato seedling roots showed the highest fluorescence intensity on the 14th day.The expression levels of antioxidant-related genes in sweetpotato roots generally increased,with a more significant increase in expression levels after H₂O₂ pretreatment.Compared with-K treatment,both H₂O₂ and DPI pretreatment could enhance the activity of antioxidant enzymes in sweetpotato leaves,and different enzyme activities showed different trends within 21 days of potassium deficiency treatment.There were varietal differences in the effects of different treatments.The experimental results showed that H₂O₂ could act as a stress signaling molecule to increase the expression level of antioxidant genes and the enzymatic activities of APX,SOD and POD in sweetpotato seedlings,thus scavenging excess ROS and effectively alleviating the inhibition of growth of sweetpotato seedlings by potassium deficiency stress.And DPI could inhibit the production of endogenous H₂O₂,maintain the antioxidant enzyme activity,protect the ROS enzymatic scavenging system of sweetpotato seedlings and avoid oxidative damage to tissues.

Saline-alkali soils are an important reserve arable land resource in China,and are generally characterized by high inorganic salt content,lack of organic matter and low soil fertility,which seriously affects China's food security.Therefore,there is a need to improve the saline soil condition,enhance soil fertility,and provide a more reliable guarantee for China's food security.In China,straw is an important agricultural organic waste,the resource utilization of straw has become an important part of sustainable agricultural development.Among them,straw return to field has been widely promoted as a core measure.A large number of studies have shown that by returning straw to the field in a reasonable manner,the structure of soil can be effectively improved,the organic carbon content of soil can be increased,and the fertility of soil can be improved.At present,how straw resources can be efficiently utilized in saline-alkali soils so that the organic carbon of saline-alkuli soils can be improved is a major issue facing Chinese agriculture.Therefore,this paper summarizes the different ways and amounts of straw return to the field to investigate its effects on the organic carbon pool and components of saline-alkali soils.On this basis,the shortcomings of straw return technology are proposed and solutions are found.In practice,appropriate treatment measures are taken for further realizing the improvement of saline-alkali land by straw return to the field.In addition,conducting saline-alkali land research is not only an in-depth analysis of a specific soil environment,but also a complex systematic project involving the intersection of multiple disciplines.In this process,various factors,including but not limited to land management,hydrogeology,ecosystem,and agricultural economics,must be fully considered.Through such efforts,we will be able to gain a deeper understanding of the characteristics of saline-alkali soils and provide a scientific basis and technical support for the improvement and utilization of these valuable resources.

The shortage of fresh water resources is an important factor restricting the sustainable development of agriculture,and the adoption of saltwater irrigation with appropriate concentration is an effective way to make up for this shortage,but the continuous use of saltwater irrigation may increase the risk of soil secondary salinization.Therefore,salt leaching should be ensured when using saltwater irrigation.In order to accurately evaluate the long-term effects of saline irrigation on soil and the effect of increased application of organic fertilizer on salt leaching,this study relied on 10 consecutive years of dry treatment and 1,3,5 g/L saline water irrigation,respectively.Applying chemical fertilizer and increasing the application of organic fertilizer based on chemical fertilizer.By analyzing soil water content,electrical conductivity,pH,organic matter,total nitrogen,available phosphorus and total phosphorus contents per 20 cm of 0-200 cm soil profile,it was found that saline irrigation with different concentrations had no significant effect on surface soil electrical conductivity and other characteristics.The saline water irrigation treatment of 5 g/L increased the soil salt content below 0-20 cm and 120 cm under the application of organic fertilizer.In addition,compared with chemical fertilizer treatment,the addition of organic fertilizer treatment significantly increased the soil surface water content,organic matter,total nitrogen,available phosphorus and total phosphorus contents,and the indexes increased by 14.16%,38.27%,32.39%,44.25% and 9.56%.It can be seen that although the application of organic fertilizer increased the soil conductivity,the soil was still in a low salt environment,and the increase of organic fertilizer increased the content of soil nutrients(especially available phosphorus)more significantly.At the same time,due to rainfall and freshwater irrigation before winter wheat planting,saline water irrigations<5 g/L in this area will not cause salt accumulation in the surface soil.

In order to explore the production performance and soil improvement effect of sweet sorghum in saline-alkali land,Zhongketian 438 sweet sorghum was planted in Southern Xinjiang,and its yield was measured,in addition,0-10 cm,10-20 cm,20-30 cm soil layers were selected on saline-alkali land before planting and after harvesting of feed sweet sorghum varieties,and the effects of soil physical and chemical properties,soil ions and soil enzyme activities were measured and compared.The results showed that the total salinity,pH value and electrical conductivity of the soil decreased after the planting of sweet sorghum.Compared with before planting,the contents of Na⁺,K⁺,HCO₃^-,Cl^-and SO₄^2- and total potassium,total phosphorus,available phosphorus and available nitrogen decreased significantly,while the contents of Ca²⁺,Mg²⁺,total porosity,organic matter,total nitrogen and available potassium increased.The content of Mg²⁺ in soil cation was highest,and the content of SO₄^2- in anion was the higher than that of Cl^-.In soil enzyme activity,the activities of catalase,sucrase and alkaline phosphatase were not significantly different,but the urease activity was significantly different.Compared with before planting,the change of 10-20 cm soil layer in different soil layers was more obvious.The results of correlation analysis showed that there was a significant positive correlation between pH value and total salinity;there was a significant negative correlation between bulk density and pH,total salinity;and a significant positive correlation between sucrase and alkaline phosphatase.The above results showed that the saline-alkali soil in this area is a soil type dominated by Na₂SO₄,and the cultivation of feed sweet sorghum in the saline-alkali soil in this area could not only harvest high-yield forage grass,but also reduce some ions in the soil to improve soil physical and chemical properties.

In order to clarify the effects of different irrigation and fertilization combinations on soil nutrients in Bashang area of Zhangjiakou on the basis of adding soil conditioner.Two two-factor tests were set:irrigation frequency and fertilizer amount,irrigation frequency and irrigation amount.Factor one was different irrigation frequency:6 d(D6),8 d(D8)and 10 d(D10).The second factor was different fertilizer dosage:100% fertilizer(F100),conditioner+100% fertilizer(PF100),conditioner+85% fertilizer(PF85),conditioner+70% fertilizer(PF70).The three factors were different irrigation amounts:100% irrigation(W100),85% irrigation(W85),70% irrigation(W70),a total of 24 treatments.The effects of different irrigation and fertilization levels on soil water content and nutrients as well as the changes of nutrients in different soil layers were analyzed.The results showed that the average water content of soil with high frequency or medium frequency irrigation(D6 or D8)was the highest in 0-60 cm soil layer.Compared with medium frequency irrigation(D8)treatment,D6 treatment could significantly increase the soil organic matter content of 0-20 cm and the total nitrogen and available potassium content of 20-40 cm soil.Compared with conventional irrigation and fertilization(F100 and W100),PF100 and PW100 could significantly increase the average soil water content,total nitrogen,available phosphorus and available potassium content in 0-20 cm soil layer,and the average organic matter and nitrate nitrogen content in 20-40 cm soil layer.In addition to the soil conditioner,water reduction and weight loss can still significantly increase the surface soil nutrient content.PF85,PW85 or PF70,PW70 could significantly increase the average soil organic matter(14.4%-19.0%),total nitrogen(2.2%-11.2%),available phosphorus(22.2%-41.7%),available potassium(4.9%-42.8%)and the average soil nitrate nitrogen in 20-40 cm soil layer(20.8%-95.0%).The correlation analysis showed that soil water content was positively correlated with organic matter,total nitrogen and soil available potassium(R²=0.081,0.092 and 0.166)under high frequency irrigation and soil available phosphorus and available potassium(R²=0.114 and 0.153)under medium frequency irrigation.In conclusion,the combination of water and fertilizer with 100% fertilization and 70% irrigation+conditioner(PF100D6 and PW70D6)is the best to improve soil nutrients under high-frequency irrigation conditions.The results can provide a scientific basis for the optimal management of irrigation and fertilization in arid northern China and other areas with similar environment.

In order to explore the effects of combined application of amino acid fertilizer and urea on soil active organic carbon components and enzyme activities in pepper,and to clarify the fertilization mode to increase the content of soil active organic carbon components in pepper.Seven treatments were set up,including no fertilization(CK),single application of urea(N0),80% urea + 20% amino acid fertilizer(N20),60% urea + 40% amino acid fertilizer(N40),40% urea + 60% amino acid fertilizer(N60),20% urea + 80% amino acid fertilizer(N80)and single application of amino acid fertilizer(N100).The changes of soil physical and chemical properties,soil active organic carbon content and enzyme activity under each treatment were studied.The results showed that the combined application of amino acid fertilizer and urea could effectively increase the contents of nitrogen,phosphorus and potassium,organic matter,enzyme activity,organic carbon and its active components in soil.The content of soil organic carbon increased with the increase of amino acid fertilizer application,and the content of soil active organic carbon components and enzyme activity increased first and then stabilized or decreased slightly with the increase of amino acid fertilizer application.The soil easily oxidized organic carbon content,particulate organic carbon content,microbial biomass carbon content,cellulase activity,catalase activity and amylase activity of N60 treatment were the best:in 0-20 cm soil layer,compared with CK treatment,they were increased by 105.50%,19.43%,142.60%,126.57%,22.28% and 308.20%,respectively.In the 20-40 cm soil layer,compared with CK treatment,it increased by 39.75%,59.32%,59.00%,130.27%,33.24% and 342.16%,respectively.Correlation analysis showed that soil total organic carbon and active organic carbon components were significantly positively correlated with enzyme activity.It can be seen that the combined application of amino acid fertilizer and urea can effectively improve the soil active organic carbon content and enzyme activity in pepper,and the treatment of 40% urea combined with 60% amino acid fertilizer has the greatest potential for improvement.

In order to explore the rapid and scientific improvement model of soil fertility in newly cultivated land,it took the maize wheat rotation system of newly cultivated land as the research object,and conducted different fertilization treatment experiments (including no fertilization control (CK),organic fertilizer 15 t/ha(OF15),chemical fertilizer (MIN),organic fertilizer 7.5 t/ha+fertilizer (OF7.5+MIN),organic fertilizer 15 t/ha+fertilizer (OF15+MIN),and organic fertilizer 30 t/ha+fertilizer (OF30+MIN)).Based on the basic data of soil physical and chemical properties such as total nitrogen,alkaline nitrogen,available phosphorus,available potassium,and organic matter,the integrated fertility index (IFI) of soil nutrients was used to quantitatively and comprehensively evaluate the soil fertility of different fertilizers.The results showed that:on the basis of applying chemical fertilizers to newly cultivated land, organic fertilizers were added to improve soil available nutrients, increasing soil total nitrogen by 108.6%-149.0%, soil alkali hydrolyzed nitrogen by 253.6%-311.0%, soil available phosphorus by 78.8%-171.6%, soil available potassium by 35.6%-80.5%, soil organic matter content by 5.8%-41.9%, soil capacity by 1.0%-8.3%, soil pH value by 3.4%-7.3%, soil fertility comprehensive index by 21.6%-27.7%, and annual yield of corn and wheat by 33.2%-127.1%. The available nutrients, organic matter, soil fertility level, and annual yield of corn and wheat in newly cultivated land all showed an increasing trend with the increase of organic fertilizer application, among which 30 t/ha of organic fertilizer had the best effect. Compared with the application of organic fertilizer alone, the combination of organic fertilizer and chemical fertilizer effectively increased soil organic matter and soil comprehensive fertility index by 12.3% and 22.0%, respectively. In summary, under the conditions of this experiment, the combination of organic fertilizer and chemical fertilizer resulted in higher soil comprehensive fertility and annual crop yield compared to single application of chemical fertilizer or single application of organic fertilizer. The treatment with 30 t/ha of organic fertilizer and 2+chemical fertilizer significantly improved the soil fertility and crop yield of newly reclaimed farmland.

The aim of this study was to investigate the effects of different nitrogen application levels and base-topdressing ratio on wheat leaf physiology,source-sink regulation of grain storage and yield in the middle and lower region of Yangtze River in Anhui Province.Using Baihumai 1 as the experimental material,three nitrogen application rates(180,210 and 240 kg/ha)with different nitrogen application levels and base ratios of 5∶1∶4,7∶1∶2 and 5∶4∶1 were set;through the determination of different source-sink indexes,in order to determine the appropriate wheat nitrogen fertilizer management model in the middle and lower region of the Yangtze River.The results indicated that with increasing nitrogen application rates(0 to 240 kg/ha),wheat leaf area index(LAI),post-flowering chlorophyll relative content(SPAD),and source organ biomass allocation showed an upward trend.The grain biomass allocation during maturity and the conversion rate of post-flowering source production capacity exhibited a trend of initially increasing and then decreasing,with the highest values observed at a nitrogen application rate of 210 kg/ha.At the same nitrogen application level,under the condition of a 7∶1∶2 base-to-topdressing ratio(base fertilizer∶tillering fertilizer∶jointing fertilizer),wheat plant had the highest leaf area index,while under a 5∶1∶4 ratio,chlorophyll content was highest.The grain biomass allocation during maturity and the economic coefficient were highest with the 7∶1∶2 base-to-topdressing ratio.Under the same base-to-topdressing ratio treatment,increasing nitrogen application improved the number of wheat spikelets and effective spikes,while the thousand-grain weight decreased with increasing nitrogen application.Grain yield showed an initial increase followed by a decrease with increasing nitrogen application,and at a nitrogen application rate of 210 kg/ha and a 7∶1∶2 base-to-topdressing ratio,wheat population potential storage capacity was large,grain-to-leaf ratio was high,and grain filling index was suitable.Wheat grain yield reached its maximum.Considering both high yield and efficiency,the optimum nitrogen fertilizer application rate of 210 kg/ha and the base-to-topdressing ratio of 7∶1∶2 were the best for the rice-stubble wheat Baihumai 1 in the middle and lower region of the Yangtze River in Anhui Province,allowing for maximum potential storage capacity and yield under these conditions.