In order to explore the molecular mechanism of low nitrogen response in quinoa, low nitrogen response genes were screened to reveal the adaptive changes in quinoa response to low nitrogen.Based on the seedling growth observation and chlorophyll synthesis detection,we analyzed the transcriptome changes of quinoa after 5 d and 30 d under nitrogen deficiency conditions.The results showed that roots were preferentially developed under nitrogen starvation condition.Older leaves turned yellow or dropped down under both low nitrogen and nitrogen starvation conditions,therefore younger leaves could maintain green.Higher NUE was shown in both low and nitrogen starvation conditions.GO enrichment analysis indicated that significantly differential expressed genes were mainly involved in integral component of membrane,membrane,oxidation-reduction process,metabolic process,ATP binding,and metal ion binding.After 5 d of low or nitrogen starvation supply,KEGG enrichment analysis showed that phenylpropyl biosynthesis and glutathione metabolism were the most significant metabolic pathways compared with high nitrogen.After 30 d of treatment,the most significant metabolic pathway was the carbon metabolic pathway.The key genes in response to low nitrogen in quinoa were further explored.The results showed that peroxidase,glutathione S-transferase and ascorbate peroxidase genes were up-regulated and their expressions were higher after 5 days of low nitrogen and nitrogen deficiency treatment.The genes of phosphoglycerate kinase,cysteine synthetase,glyceraldehyde 3-phosphate dehydrogenase (NADP)and phosphoenolpyruvate carboxylase were up-regulated and the expression levels were higher after 30 days of low and low nitrogen treatment.The results of qRT-PCR agreed with the RNA-Seq.

In order to screen out suitable water and nitrogen combinations for watermelons in Yellow River irrigation area of Ningxia, different water and nitrogen treatments were designed to study the effects of water and nitrogen interaction on SPAD value of watermelon leaves, fruit quality,yield and nitrogen uptake and utilization. The results showed that SPAD values were higher by W1N4,W2N3,W2N4,W3N3 and W3N4 treatment,the quality was better under nitrogenous fertilizer amounts at N2 and N3.The yield was the highest under W3N4 treatment,reaching 76 565.36 kg/ha and increased by 8.34% to 37.57% compared with other treatments significantly.Followed by W3N2 and W3N3 treatment.Compared with other levels,when the irrigation water level was W1,the water use efficiency of facility watermelon irrigation was higher.Among them,the irrigation water use efficiency of W1N3 and W1N4 treatment was higher,reaching 43.91,45.32 kg/ha respectively,while it was significantly increased by 14.00% to 56.40% from other treatments.Fruit nitrogen accumulation and total nitrogen accumulation under W3N4 treatment were all the highest compared with other treatments significantly,increasing by 22.75% to 192.36% and 17.00% to 123.39% respectively compared with the other treatments.Partial factor productivity of nitrogen and nitrogen fertilizer utilization rate under W3N2 treatment were all the highest compared with other treatments significantly.Partial factor productivity of nitrogen increased by 11.00% to 343.68%separately compared with the other treatments and nitrogen fertilizer utilization rate increased by 3.34 to 10.02 percentage points compared with other treatments.The correlation analysis showed that SPAD,the center of soluble solids,Vc,yield,irrigation water use efficiency and nitrogen accumulation,were all significantly positively correlated with each other,and they were significantly negatively correlated with partial factor productivity of nitrogen and nitrogen use efficiency,the edge of soluble solids was positively correlated with nitrogen accumulation of the plants,and negatively correlated with partial factor productivity of nitrogen and nitrogen use efficiency.To sum up,the watermelon had better quality when nitrogenous fertilizer amounts were N2(80 kg/ha) and N3(160 kg/ha),the yield-increasing effect was the best under the combination of water amount for W3(2 200 m³/ha)and nitrogenous fertilizer amount for N4(240 kg/ha).The interaction between high amount of irrigation water and nitrogenous fertilizer application is beneficial to the nitrogen absorption in watermelon,and the interaction between low nitrogen application amount and high nitrogenous fertilizer amount is conducive to utilization of nitrogen fertilizer.

Abstract:To explore the effects of phosphorus fertilizer reduction ratio and phosphorus fertilizer management method on tomato yield,phosphorus utilization rate and soil fertility level under simultaneous reduction of chemical fertilizer nitrogen,phosphorus and potassium in high fertilizer application areas,an experiment was conducted in a greenhouse located in Dingxing County,Hebei Province.Overwintered long-season tomato was chosen as the experimental plant.Treatments included CF(N-P₂O₅-K₂O,1 009.5-774.0-1 458.0 kg/ha),P1(N-P₂O₅-K₂O,750.0-375.0-1 125.0 kg/ha),PB2(N-P₂O₅-K₂O,750.0-225.0-1 125.0 kg/ha),PT2(N-P₂O₅-K₂O,750.0-225.0-1 125.0 kg/ha),P3(N-P₂O₅-K₂O,750.0-75.0-1 125.0 kg/ha)and P4(N-P₂O₅-K₂O,750.0-0.0-1 125.0 kg/ha).Fertilizer phosphorus was applied basally in the PB2 treatment,and the other fertilizer-reduced treatment fertilizer phosphorus was applied in a "Basal dressing and topdressing" method.The result showed that compared to CF,tomato yield of PT2 treatment over the three-year period revealed an average increase of 12.0%,with the highest increase.After three years of fertilizer reduction,the root dry weight of P1,PB2 and PT2 significantly increased,along with improvements in the chemical phosphorus fertilizer utilization rate,phosphorus fertilizer agronomic utilization rate,and the chemical phosphorus fertilizer harvest index.Compared to CF,PT2 treatment resulted in an increase in root shoot ratio of 48.2%, phosphorus fertilizer recovery rate and phosphorus fertilizer harvest index increased by an average of 32.9 and 2.7 percent points, phosphorus fertilizer agronomic utilization rate was 9.02 times higher than that of CF.PT2 treatment was the highest among all fertilizer reduction treatments.Compared to the CF treatment,soil $NO_3^{-}$-N,Available P and Available K contents were reduced by an average of 8.2%—14.9%,4.4%—19.9%,and 7.3%—24.8%,respectively,over the three-year period.In conclusion,a 35.2% reduction in chemical fertilizer,which included a 70.9% decrease in chemical phosphorus fertilizer,did not have a negative impact on yield in greenhouses with excessive fertilizer use.Additionally,the combination of "Basal dressing and topdressing" method for phosphate management enhances tomato yield in comparison to basal dressing alone.This method also reduces available phosphorus content and increases the efficiency of chemical phosphorus fertilizer utilization.

In order to investigate the effect of reducing nitrogen and increasing density on the yield formation characteristics of ratooning rice,hybrid rice variety Chuangliangyou 669 was used as the material to conduct two years of field experiments under conditions of three nitrogen application rates(N1:180 kg/ha;N2:153 kg/ha;N3:126 kg/ha)and two plant row spacing(M1:20.0 cm×16.7 cm;M2:16.7 cm×16.7 cm).The results showed that:reducing nitrogen reduced the leaf area index(LAI)of ratooning rice,but increasing density within a reasonable range of nitrogen reduction could increase the LAI of the main and ratooning seasons.The LAI of N1M2 and N2M2 was higher in the interaction treatments.Reducing nitrogen and increasing density both reduced the SPAD value of ratooning rice leaves,but the effect of density was not significant.Reducing nitrogen led to a decrease in dry matter weight,while increasing density could significantly increase dry matter weight.The interaction treatment of N1M2 and N2M2 had a higher dry matter weight.Reducing nitrogen reduced the yield of ratooning rice,but increasing density within a reasonable range of nitrogen reduction could increase yield.The interaction treatment of N1M2 and N2M2 had a higher yield.Reducing nitrogen significantly reduced the number of effective panicles in the main season,the total number of grains per panicle,and the regeneration rate and number of effective panicles in the ratooning season.However,increasing density had a compensatory effect on the number of panicles.Reasonable nitrogen reduction and density increase(N2M2)could coordinate the relationship among yield components and achieve higher yields.The correlation analysis showed that reasonable nitrogen reduction and density increase increased the effective number of panicles and total grains per panicle in the main season,as well as the effective number of panicles in ratooning season mainly by increasing LAI and dry matter weight of the main and ratooning season,and thereby improving the yield of ratooning rice.Overall,the nitrogen reduction and density increase treatment N2M2(nitrogen rate of 153 kg/ha,plant row spacing of 16.7 cm×16.7 cm)can save 15% nitrogen and achieve a higher yield.

Soil organic carbon and humus components are affected by soil quality,fertilization management measures and other factors.In order to clarify the regulation effect of long-term chemical fertilizer application on soil organic carbon(SOC)and soil humus components in different soil layers,a 43 a(2021)long-term fertilization experiment was conducted in Laiyang,Shandong Province.Six treatments were selected:low nitrogen fertilizer(N1),high nitrogen fertilizer(N2),high nitrogen fertilizer combined with phosphorus fertilizer(NP),high nitrogen fertilizer combined with potassium fertilizer(NK),high nitrogen combined with phosphorus and potassium fertilizer(NPK)and no fertilizer control(CK).The results showed that compared with CK,N1 could significantly increase the SOC content of 0—5 cm,with an increase of 22.84%.Single nitrogen fertilizer treatment could significantly increase the SOC content of 5—10 cm,with an increase of 20.94% and 28.60% in N1 and N2,respectively.N1 could significantly increase the SOC content of 10—20 cm,with an increase of 17.05%,while other treatments had no significant change.Compared with CK,N1 could significantly increase the content of humic acid(HA)in 10—20 cm and 20—30 cm soil layers,with an increase of 22.86% and 40.49%,respectively,while there was no significant change in 0—10 cm soil layer.NP could significantly increase the content of fulvic acid(FA)in 0—5 cm and 5—10 cm soil layers by 89.44% and 124.63%,respectively.NK could significantly increase the content of FA in 10—20 cm soil layer by 100.22%,and NPK could significantly increase the content of FA in 20—30 cm soil layer by 107.48%.N1 could significantly increase the content of humin(Hu)in 0—5 cm soil layer,with an increase of 69.34%.N2 could significantly increase the content of Hu in 5—10 cm soil layer,with an increase of 66.18%.N1 could significantly increase the content of Hu in 10—20 cm soil layer,with an increase of 79.50%,while there was no significant change in 20—30 cm soil layer.In summary,under the conditions of this experiment,long-term application of chemical fertilizers can effectively improve the fixation of soil organic carbon in non-calcareous fluvo-aquic soil and change the composition of soil humus,and the effects of different fertilization strategies are quite different.Among them,the effect of single application of nitrogen fertilizer on carbon sequestration is better.

Calcium and potassium are important mineral nutrient elements in wheat.It is significant to explore the related genetic mechanisms and effects on human nutritional health.To provide a theoretical basis for biofortification breeding of trace elements in wheat grains,we used 164 F₆ recombinant inbred lines(RILs)derived from Avocet/Chilero(AC)and 175 F₆ RILs derived from Avocet/Huites(AH).Our investigation focused on phenotypic variations in grain calcium(GCa)and grain potassium(GK)content in five environments.QTL mapping was conducted with diversity arrays technology(DArT)chip.Nineteen QTLs associated with grain calcium content were identified,distributed on chromosomes 1A,1D,2A,2B,3A,3D,4A,4B,4D,5A,5B,7A,7B,and 7D,explaining 3.23%—16.29% of phenotypic variation.Simultaneously,23 QTLs linked to grain potassium content were identified on chromosomes 1B,2A,2B,3A,3B,4A,4D,5A,6A,6B,and 7D,explaining 3.31%—24.66% of phenotypic variation.QGCa.haust-1A,QGCa.haust-AC-5A and QGK.haust-AC-2A.2 were located in multiple environments.QGCa.haust-1A and QGCa.haust-AC-5A explained 7.82%—12.72% and 9.68%—15.57% of phenotypic variation,and the physical intervals were 498.67—532.21 Mb and 461.52—486.26 Mb,respectively.QGK.haust-AC-2A.2 explained 8.15%—15.20% of phenotypic variation,with a physical range of 354.61—462.37 Mb.The genetic effect analysis of QGCa.haust-1A,QGCa.haust-AC-5A,and QGK.haust-AC-2A.2 showed that each locus effectively increased the calcium and potassium content in wheat grain.Aggregation effect analysis indicated that the lines with QGCa.haust-1A and QGCa.haust-AC-5A effect loci had highly significantly higher calcium content than those with only a single locus.In summary,three stable loci of grain calcium and potassium content are mapped on chromosomes 1A,2A,and 5A,which could significantly increase calcium and potassium content in wheat grain.

To explore the effects of fertilizer reduction and organic fertilizer application on physicochemical properties and microbial community structure of tobacco-planting soil,and provide theoretical reference for fertilizer reduction and rational application of organic fertilizer in tobacco production.Using conventional fertilization without organic fertilizer as control(CK),Illumina high-throughput sequencing technology combined with bioinformatics,the changes of soil physical and chemical properties and microbial community structure under different treatments such as 10% reduction of fertilizer(T1),10% reduction of fertilizer+sesame cake fertilizer(T2),10% reduction of fertilizer + humic acid fertilizer(T3),and 10% reduction of fertilizer + sesame cake fertilizer + humic acid fertilizer(T4)were analyzed.The results showed that compared with CK,soil nutrient content and soil enzyme activity decreased under T1 treatment,and soil physical properties were slightly improved.Combined with organic fertilizer,soil nutrient and physical properties were further improved,bulk density decreased,moisture content and porosity increased,and the contents of available phosphorus and available potassium under T2 and T4 treatment were significantly higher than those under CK and T1 treatment.The enzyme activity of soil treated with organic fertilizer increased significantly.Combined application of organic fertilizer increased the bacteria and fungi in tobacco-growing soil,among which the dominant bacteria were Proteobacteria and Actinobacteriota.Followed by Firmicutes,Bacteroidota,Chloroflexi and Acidobacteriota.The dominant fungal groups are Ascomycota,Anthophyta,Mortierellomycota,Chlorophyta,Ciliophora and Basidiomycota.The Alpha diversity index showed that the reduction of fertilizer decreased the richness of microbial community,but the combined application of organic fertilizer increased the diversity index of bacterial and fungal communities,and the bacterial community richness increased more significantly.RDA analysis showed that the important soil physicochemical factors affecting soil microbial community structure and diversity included organic matter,available potassium,alkali-hydrolyzed nitrogen,available phosphorus and soil physical properties,etc.Soil physicochemical factors had a greater impact on bacterial community structure.In conclusion,under the condition of fertilizer reduction,organic fertilizer combined with organic fertilizer can significantly improve soil nutrients,physical properties,soil enzyme activity and microflora structure,especially when combined with sesame cake fertilizer and humic acid fertilizer treatment.

To improve the applicability of biochar in saline-alkali agroecosystem,the effect and microbial mechanism of modified biochar were studied.In a 2-year field experiment,common biochar(4.5 t/ha),nitrogen-rich modified biochar(7.5 t/ha)and phosphorus-rich modified biochar(15.0 t/ha)were added to investigate their impact on crop grain yield,soil physicochemical properties and soil microbial diversity.It had been observed that the addition of biochar enhanced the quality of saline-alkali soil,with nitrogen-rich modified biochar and phosphorus-rich modified biochar demonstrating more notable effects.Biochar could boost crop yield,improve soil structure and reduce soil bulk density in saline-alkali land.The effects of the three biochar types were not consistent.Among them,the application of 15.0 t/ha phosphorus-rich modified biochar showed favorable responses,with grain yield of(8.92±0.12)t/ha,representing a 110% increase compared to the control group.Biochar affected soil microbial diversity.Common biochar increased soil microbial diversity,whereas phosphorus-rich modified biochar decreased it.With the continuous addition of biochar,soil physical and chemical properties could affect the relationship between soil microorganisms and plant structure,weakening their relationships.In this study,the application of 15.0 t/ha phosphorus-rich modified biochar was recommended to improve saline-alkali agroecosystem.

To clear under the condition of slow release nitrogen fertilizer applying different content of maize development rule of the diurnal change of photosynthetic characteristics and growth,the light response curve was to fit,so as to farming-pastoral zone of spring maize cultivation and nitrogen utilization to provide theoretical basis.This study took Guangde 5 as the research object,and based on the long-term positioning experiment in 2018,the leaves ear position in spinning—tasseling stage of maize were mesured and analyzed under six nitrogen gradient of N 0(N0,CK), 120(N8), 180(N12), 240(N16), 300(N20),360(N24) kg/ha in 2019 and 2020. SPAD value, intercellular carbon dioxide concentration, stomatal conductivity, diurnal variation of net photosynthetic rate, transpiration rate, light response curve and dry matter accumulation rule.The results showed that with the increase of nitrogen fertilizer application, the changes of SPAD value, net photosynthetic rate, transpiration rate and stomatal conduction degree day of maize increased first and then decreased,and N16 treatment was the highest,and intercellular carbon dioxide concentration was the lowest.The changes of net photosynthetic rate,transpiration rate and stomatal conduction degree day showed unimodal curve.The light response curve fitting analysis showed that the maximum net photosynthetic rate of N16 treatment was the highest.In 2019 and 2020,N16 treatments were 37.48%,29.51%,31.85%,18.17%,37.32% and 80.04%,59.73%,50.30%,6.42%,62.51% higher than N0,N8,N12,N20 and N24 treatments,respectively.Dry matter mass accumulation in whole plant and ear were positively correlated with maximum net photosynthetic rate,apparent quantum efficiency and SPAD value.Comprehensive analysis showed that the most suitable nitrogen fertilizer application rate in western Inner Mongolia was 240 kg/ha.

In order to study the effect of applying N,P and K fertilizer on the yield and nutrient use efficiency of oil sunflower under the double cropping pattern of winter wheat-summer oil sunflower in Southern Shanxi,a field plot fertilizer experiment was carried out with Linkui 4 from 2019 to 2021.Four fertilization treatments including NPK,PK,NK and NP were set up.The effects of different fertilization treatments on yield response,agronomic efficiency and fertilizer use efficiency of N,P,K were analyzed.The results showed that the three-year average yield of oil sunflower treated with NPK was 3 634 kg/ha(3 502—3 818 kg/ha),which was 19.6%,12.1%,13.7% higher than that of PK/NK/NP,respectively.PK treatment had the lowest yield.The average yield responses of N,P and K fertilizers were 588.8(481.0—704.7 kg/ha),391.8(296.0—488.7 kg/ha),438.2 kg/ha(329.3—629.7 kg/ha),respectively.The agronomic efficiencies of N,P and K were 3.8(2.8—4.9 kg/kg),3.1(2.1—4.1 kg/kg),2.9 kg/kg(2.2—4.2 kg/kg),respectively.The aboveground accumulations of N,P and K were 174.4(172.5—176.8 kg/ha),60.0(58.3—61.8 kg/ha),241.1 kg/ha(236.2—246.8 kg/ha),respectively.The nutrient use efficiency of N,P,K was 36.3%(36.0%—36.7%),15.7%(15.3%—16.2%)and 47.1%(46.0%—47.9%),respectively,of which K>N>P.So the application of N,P and K fertilizer could not only significantly increase the oil sunflower yield but also the aboveground accumulation of N,P and K.Among the three kinds of NPK fertilizers,N increased the yield most,and K uptake by the aboveground part and utilization rate of oil sunflower was the highest.Therefore,in the production we should pay attention to the reasonable application of N,P and K,while N and K should be supplemented by seed fertilizer and topdressing.

In order to study the differences in yield and nitrogen utilization,transport and accumulation of different winter wheat cultivar(line)types in the Northern Huanghuai,the yield traits and nitrogen utilization efficiency of 29 and 26 winter wheat cultivars(lines)for testing in the Northern Huanghuai wheat area were investigated and analyzed in 2021—2022 and 2022—2023,respectively.Through cluster analysis,wheat was classified into four types:high-yielding,medium-high-yielding,medium-yielding and low-yielding.Nitrogen content of wheat stems,leaves,spikes,and grains at maturity were measured at anthesis and maturity,respectively,to analyze the relationship between parameters related to nitrogen utilization traits and yield.The results showed that the average yields among high-yielding,medium-high-yielding,medium-yielding and low-yielding varieties(lines)differed significantly from 2021 to 2023,with the number of spikes per hectare of high-yielding varieties significantly higher than that of other types.At the anthesis stage,the nitrogen accumulation and distribution rate of each organ were stems and sheaths>leaves>spikes;at the maturity stage,the nitrogen accumulation of each organ was grains>stems and sheaths>spikes>leaves.The post-anthesis nitrogen accumulation,pre-anthesis nitrogen transport and its contribution to the grain of different varieties of wheat were higher in high-yielding varieties(lines),and the pre-anthesis nitrogen transport and its contribution to the grain were greater than the post-anthesis nitrogen accumulation and its contribution to the grain.Nitrogen utilization efficiency,nitrogen harvest index,nitrogen accumulation at anthesis and nitrogen accumulation at maturity were significantly and positively correlated with wheat grain yield.Therefore,water and fertilizer management can be carried out through the nitrogen uptake and transfer pattern and distribution characteristics of different varieties,or selecting and breeding wheat varieties with high nitrogen utilization efficiency to achieve high-yield and high-efficiency production of wheat.

In order to provide theoretical basis for straw fertilizing high-yield field and improving saline-alkali field in the process of continuous high yield and stable yield of spring corn in Inner Mongolia plain irrigation area.This study set up a positioning test of corn straw returning to the field for 1 to 4 years (HT1—HT4), taking the straw not returning to the field as the control (CK). Soil organic carbon content, total nitrogen content, available nitrogen content, available phosphorus content, cation exchange capacity, pH value and acid-base buffer curve were measured before spring sowing and during harvest. The results showed that, the relative change rates of soil organic carbon content, total nitrogen content, available nitrogen content, available phosphorus content and cation exchange capacity were 1.34%—3.62%, 0.20%—1.51%, -0.11%—0.78%, 0.89%—6.36% and 0.09%—0.41% during harvest period of HT1—HT4 compared with that before spring sowing. The relative change rates of soil organic carbon content, total nitrogen content, available nitrogen content, available phosphorus content and cation exchange capacity were 1.57%, -0.02%, -0.45%, -0.15% and -0.05% in CK harvest period compared with that before spring sowing. Soil pH value of HT2, HT3 and HT4 was significantly lower than that of CK. The buffer capacity of soil to alkali was HT4>HT3>HT2>HT1>CK. In summary, with the increase of straw returning years, soil carbon sequestration capacity, fertilizer retention capacity and buffering performance increase, and the ability to effectively resist drastic changes in soil pH value caused by fertilizer application and other factors was enhanced, soil quality was significantly improved by straw returning to field for fertilizer cultivation and soil improvement measures.

In order to explore the suitable phosphate fertilizer application methods in the Huang-Huai area,this research conducted field experiments to investigate the dry matter accumulation,root morphological indexes,available phosphorus content and phosphatase activity in different soil layers,maize yield and its component factors of four phosphate fertilizer application methods(conventional broadcast (P1),layered application (P2),strip application (P3) and hole application (P4)).The results showed that the ear length and kernel row number of P2 and P4 were significantly increased by 22.57%,16.81% and 15.19%,7.60% compared with P1.The grain number per spike of P2,P3 and P4 were significantly increased by 25.26%,13.86% and 17.00% compared with P1,respectively.Additionally,a decrease of spikes per area was found in P2 (15.30%) compared with P1.The yields of P2 and P4 were significantly increased by 15.20% and 10.79% compared with P1.Among root traits,the root length,root surface area,root volume and root tip number were significantly affected by the phosphorus application method.The root length under P2 and P4 treatments was significantly increased by 30.41% and 33.75% compared with P1.The root surface area of P2 treatment was significantly increased by 23.77% compared with P1.The root surface area of P4 treatment was significantly increased by 29.60% and 21.70% compared with P1 and P3 treatments,respectively.The root volume and root tip number of P2 and P4 treatments were significantly higher than those of P1 and P3.The analysis of soil available phosphorus content showed that the available phosphorus contents of P2 and P4 were significantly higher than that of P1 in the soil layer of 10—20 cm at three-leaf stage of maize.The available phosphorus contents of P2,P3 and P4 in the 0—20 cm soil layer were lower than that of P1,and the available phosphorus content of P4 in the soil layer of 20—30 cm was significantly lower than that of P1 at maturity stage.Correlation analysis showed that there was a significant positive correlation between acid phosphatase activity and soil available phosphorus content in the 10—20 cm soil layer at three-leaf stage of maize.The acid phosphatase activity and soil available phosphorus content in P2 and P4 treatments were higher in this soil layer,which was conducive to the conversion of soil phosphorus into maize absorbable state.In conclusion,compared with the traditional application method,layered phosphorus application and cave phosphorus application can improve the soil phosphorus availability in the early stage of maize,promote the growth and development of roots,and then increase the summer maize yield,so they are more suitable application method for corn phosphorus fertilizer in Huang-Huai area.

Partial substitution of organic fertilizer nitrogen for chemical fertilizer nitrogen is one of the ways to achieve sustainable crop development.This study explored the appropriate ratio of wheat organic nitrogen partial substitution for chemical nitrogen,as well as the characteristics of nitrogen accumulation,transportation,and utilization after substitution,in order to provide a basis for nitrogen fertilizer reduction and efficiency enhancement technology for winter wheat in Hebei Region.Field experiments of the following nine treatments were conducted in Ningjin,Hebei from 2021 to 2023:T1,non-nitrogen,and application of chemical P and K fertilizer alone;T2,high efficiency fertilization treatment,and application of chemical N,P and K fertilizer alone;T3—T7,substitution of 20%,40%,60%,80% and 100% the chemical N rate of T2 with organic fertilizer,respectively;T8,traditional fertilization,and application of chemical N,P and K fertilizer alone;T9,substitution of 100% chemical N rate of T2 with organic fertilizer,and spraying liquid nitrogen fertilizer at the erecting stage.The results of two years of experiments showed that the 100% substitution rate+liquid nitrogen treatment could achieve the highest wheat yield.Secondly,the yield of the 40% substitution rate treatment was equivalent to that of the high efficiency fertilization treatment,and it was much higher than that of the traditional fertilization treatment in the second year of the experiment.The 100% substitution rate+liquid nitrogen treatment increased the nitrogen content in stems and leaves by spraying available nitrogen during the erecting period,and the nitrogen accumulation in plants was equivalent to that of high efficiency fertilization and traditional fertilization treatments.Treatment with 40% and 80% substitution rates also achieved nitrogen accumulation equivalent to the highly efficient fertilization treatment.The 20%—100% substitution rate treatment (including liquid nitrogen treatment) could achieve a higher nitrogen transfer rate in stems and leaves,as well as the contribution rate of nitrogen transfer to grain.Among them,the 100% substitution rate+liquid nitrogen treatment had good fertilizer nitrogen absorption and utilization effect,achieving higher fertilizer nitrogen accumulation,nitrogen utilization rate,and nitrogen harvest index.Nitrogen fertilizer effect of the 100% substitution rate+liquid nitrogen treatment was equivalent to or slightly higher than that of highly efficient fertilization treatment.Secondly,the treatment with the 40% substitution rate had a similar or slightly lower nitrogen fertilizer effect than the highly efficient fertilization treatment.In summary,the 100% substitution rate+liquid nitrogen treatment showed better wheat yield,plant nitrogen accumulation,nitrogen transport rate,grain nitrogen accumulation,and nitrogen efficiency,followed by the 40% substitution rate treatment.

To investigate the influence of green manure cultivation on the carbon and nitrogen content of saline-alkali soil under freshwater leaching,a field experiment was conducted from October 2021 to May 2022.Three treatments were set up:winter fallow(T1),Dongmu 70 rye(T2),and rape(T3).The spatial distribution of soil organic carbon(SOC),nitrate nitrogen($\mathrm{NO}_{3}{ }^{-}-\mathrm{N}$),and ammonium nitrogen($\mathrm{NH}_{4}^{+}-\mathrm{N}$)in the soil and leachate were measured.The results revealed that in the 0—30 cm soil layer,the soil organic carbon content of T1,T2,and T3 increased from 6.20,6.58,7.24 g/kg before leaching to 6.48,7.39,8.06 g/kg after leaching,representing an increase of 4.41%,12.20%,and 11.23%,respectively.After freshwater leaching,the nitrate nitrogen content in the 0—60 cm soil layer of T1 was significantly higher than that of T2 and T3.In the 0—30 cm soil layer,the respective reductions for each treatment were 42.42%,3.85%,and 10.84%.In the 60—90 cm soil layer,the reductions were 1.38%,7.96% and 18.11%.There were no significant differences in ammonium nitrogen content among the different treatments before leaching,but after leaching,the highest ammonium nitrogen content was observed in T2.In conclusion,after leaching irrigation,the soil organic carbon content in different soil layers increased compared to before leaching,while soil nitrogen showed a significant decrease.Analysis of nitrogen content in the soil and leachate indicated that the main nitrogen loss caused by leaching irrigation was in the form of nitrate nitrogen.Compared to winter fallow farmland,the cultivation of rapeseed green manure had a significant effect on increasing soil nitrogen content,while Dongmu 70 green manure was the the most effective in reducing soil nitrogen loss.

In order to solve the problems of non-point source pollution caused by a large amount of nitrogen loss in the early growth stage and insufficient nitrogen supply in the late growth stage of dry land millet in Ningxia,which led to premature senescence and yield reduction.Under the nitrogen application rate of 135 kg/ha,five nitrogen treatments were designed according to the ratio of base fertilizer∶jointing fertilizer∶ear fertilizer.The ratio of base fertilizer∶jointing fertilizer∶ear fertilizer was 6∶2∶2(N1,nitrogen fertilizer was in front),6∶0∶4(N2,conventional nitrogen management),2∶4∶4(N3,the front nitrogen moves backward),4∶6∶0(N4,front nitrogen moved back),4∶0∶6(N5,nitrogen from front to back),no nitrogen fertilizer treatment(CK).The effects of nitrogen fertilizer backward movement on dry matter accumulation,grain yield and nitrogen absorption and utilization efficiency of broomcorn millet were studied.The purpose of this paper was to explore the best nitrogen application period and amount of broomcorn millet.The effects of nitrogen application on dry matter accumulation,grain yield and its components,and nitrogen use efficiency of broomcorn millet in different growth stages were significantly different,and all of them were significantly higher than CK.The effects on grain yield and its components of broomcorn millet were significantly higher than that of CK,and the grain yield of each treatment increased 18.9%,26.6%,30.8%,22.1% and 23.3% compared with CK,respectively.Nitrogen accumulation of each treatment showed spike>stems>leaf>root,and significantly higher than CK.N use efficiency was significantly higher than CK,and N backward treatment(N3,N4,N5)increased by 4.75,3.08 and 2.99 percent points,respectively,compared with nitrogen pre-treatment(N1).Based on principal component analysis and correlation analysis,N3(base fertilizer∶jointing fertilizer∶heading fertilizer ratio of 2∶4∶4)was the best plan for the backward transfer of nitrogen fertilizer in broomcorn millet production in the mountainous area of Southern Ningxia.The appropriate delayed nitrogen transfer could promote the accumulation and transport of dry matter and nitrogen,improve the nitrogen metabolism of broomcorn millet leaves at the late growth stage,delay leaf senescence,and improve the yield of broomcorn millet.

Define the cultivation measures of long-leaf tobacco seedlings in tobacco-rice rotation area to promote the early growth and rapid development of paddy-tobacco.Yunyan 87 was used as the material.The effects of three factors on dry matter and nutrient accumulation and distribution,and fertilizer use efficiency of flue-cured tobacco were studied,namely,the aperture of nursery site(136,200 pores),microbial agent(substrate with Miaoqiangzhuang microbial agent,substrate without microbial agent),and transplanting leaf age(8-leaf transplanting,10-leaf transplanting).The results showed that increasing the aperture of nursery site and adding microbial agent in the substrate to cultivate long-leaf tobacco seedlings could increase dry matter accumulation,improve dry matter distribution,increase nitrogen,phosphorus and potassium accumulation,promote fertilizer absorption efficiency,and increase fertilizer utilization rate and production efficiency;the contribution rates of aperture of nursery site,microbial agent,transplanting leaf age and the interaction of three factors to dry matter accumulation were 22.87%,27.73%,37.41% and 11.99%,respectively.The contribution rates to nitrogen accumulation were 20.34%,23.45%,33.62% and 22.59%,respectively.The contribution rates of phosphorus accumulation were 24.41%,27.81%,32.85% and 14.93%,respectively.The contribution rates of potassium accumulation were 15.48%,26.05%,34.61% and 23.86%,respectively.The contribution rates to nitrogen efficiency were 20.81%,44.67%,23.11% and 11.41%,respectively.The contribution rates of phosphorus fertilizer efficiency were 32.15%,31.66%,14.91% and 21.28%,respectively.The contribution rates of potassium fertilizer efficiency were 25.31%,38.71%,31.67% and 4.31%,respectively.In Hunan paddy-tobacco growing area,increasing the aperture of nursery site and adding microbial agents to the substrate can make up for the defects of two-stage seedling raising,and jointly improve nutrient uptake and fertilizer utilization efficiency,which has a certain popularization value in flue-cured tobacco production.

Using tomato as experimental material and using sand cultivation method,the effects of exogenous addition of potassium humate and amino acid fertilizer on the metabolic pathway,plant biomass,nutrient uptake,yield and quality index of tomato at seedling stage were explored.The experimental results showed that:the root growth of tomato increased by 118% and 13% at the seedling stage and flowering and fruiting stage under potassium humate treatment,and the nitrogen,phosphorus and potassium carrying in the stem increased significantly by 31%,45% and 26%.The amount of phosphorus carried out in leaves increased significantly by 92%.Phosphorus carrying from fruit also increased significantly by 45%.The metabolomic results showed that potassium humate treatment mainly affected tomato glutathione metabolism,glycine serine and threonine metabolism,porphyrin and chlorophyll metabolism,while amino acid fertilizer treatment mainly affected tomato propionic acid metabolism,pantothenic acid and coenzyme A biosynthesis and TCA cycling.Compared with the blank control,the yield of tomatoes under potassium humate treatment increased by 35%,the fresh weight and dry weight of the aboveground increased by 21% and 5%,and the soluble sugar content,sugar-acid ratio and soluble solids content in tomato fruits were also significantly increased,with increases of 30%,41% and 0.39 percentage point,respectively.The application of amino acid fertilizer significantly increased the root length,aerial fresh weight and fruit yield of tomato during the flowering and fruiting stage,which increased by 19%,18% and 26%,respectively,and the soluble solids content of tomato fruit increased by 0.30 percentage point,the solid-acid ratio increased by 16%,and the weight per fruit increased by 15.6%.In summary,the application of potassium humate and amino acid fertilizer can significantly change the carbon and nitrogen metabolism process of sand tomato plants,promote tomato growth and fruit quality,and is an effective agronomic measure to achieve high-yield and high-quality tomato cultivation.

In order to explore the effect of applying biochar on the improvement of soil physical and chemical properties in pear orchards and the continuous impact on the fruit quality of Huangguan pear,the positioning experiments for four consecutive years were conducted to provide theories and technologies support for rational and efficient fertilization in Huangguan pear orchards in Hebei Province.The experiment was carried out in the Huangguan pear experimental base in Jinzhou City,Hebei Province.Taking the treatment without biochar as the control(CK),the application of 0.45(B1),0.90(B2),1.35(B3),1.80 kg/m²(B4)4 treatments were used to study the effects of different amounts of biochar on soil organic matter,nitrate nitrogen,available phosphorus,available potassium,electrical conductivity and pH,and explored the effects on fruit quality(such as total soluble sugar,titratable acid,firmness,soluble solids,and single fruit weight)of Huangguan pear during ripening.The application of biochar for four consecutive years significantly reduced the soil nitrate nitrogen content,and increased the contents of organic matter,available phosphorus,available potassium and pH in the surface layer(0-20 cm),and the effect on the surface layer(0-20 cm)was greater than that in the 20-40 cm soil layer.B3 treatment had the best improvement effect on soil nutrients.The influence of soluble solid content on the fruit quality of Huangguan pear showed an increasing trend,and titrable acid showed a decreasing trend.There was no significant difference between B2 and B3 treatments on the quality of Huangguan pear.Considering the long-term cumulative effect of soil and the economic cost of biochar,0.90-1.35 kg/m² biochar application rate was recommended as the appropriate application rate.Combined with the analysis of the effects of the amount of biochar on the soil physicochemical properties and pear quality,under this test condition the recommended amount of biochar was 0.90 kg/m².

To reveal the soil factors that formed the quality characteristics of Hebei chestnut,54 typical chestnut orchards from 8 counties in Hebei Province were selected as the objects,and the contents of 9 mineral elements in the soil were studied by using significance,correlation and principal component analysis.The results showed that there were no significant differences in contents of Mg and Na,but there were significant differences in N,P,K,Ca,Fe,Mn and Cu contents in the soil of chestnut plantations in the main chest nut production areas.The N content in the soil of chestnut orchards was generally below the level of 3,and the P content was generally above the level of 3.The K content was generally at a low level,which was below the level of 5.The correlation of the contents of metal elements such as Ca,Mg,Fe,Mn,Cu and Na were significantly correlated with each other in soil.They were also significantly correlated with P element,and the correlation with N content was generally weak.Principal component analysis showed that mineral elements in the first 3 principal components reflect the total information content 73.521%.The contribution rate of the first principal component accounted for 44.678%,and the elements which included Ca(0.871),Cu(0.840),Fe(0.809)and Mg(0.806)were the main factors.It showed that the metal trace element content contributes more to the principal component.The comprehensive score was based on the mineral elements content of different chestnut orchards,which decided the order of high and low.The highest score was in Qianxi County(0.591 8).The ranking of the soil quality in the main chest nut production areas was:Qianxi>Qinglong>Xinglong>Kuancheng>Shahe>Zunhua>Xindu>Funing.To sum up,it is confirmed that the comprehensive scores of metal elements contents such as Ca,Mg,Fe,Cu can be used to evaluate the soil quality by using principal component analysis.It was advisable to select high K and low P compound fertilizer,and it was recommended to apply multiple elements mixed fertilization as a supplementary measure to improve the soil quality level of chestnut orchards.

The effects of long-term manure application on water-dispersible phosphorus (P)content and morphological distribution in three zonal soils were explored to provide references for understanding the risk assessment of P loss. The soil samples were collected from the farmland in Daxing Beijing(Fluvo-aquic soils),Yueyang Hunan(Red earths)and Zhanjiang Guangdong(Humid-thermo ferralitic)from May 2021 to August 2021,the sample was a composite mix of five individual surface soil cores (0—20 cm). The characteristics of water-dispersible P,morphological distribution,and minerals contents were studied. Compared with the treatment without manure application,the water-dispersible P content of the three zonal soils in Daxing,Yueyang and Zhanjiang was significantly increased by 1.15,1.32,14.00 times,respectively. Long-term application of manure significantly changed the distribution ratio of different forms of water-dispersible P in the total soil water-dispersible P,and the proportion of particulate P in Daxing and Yueyang soils decreased significantly by 30.22 and 14.68 percentage points,respectively,while the proportion of dissolved P significantly increased by 29.83 and 28.06 percentage points,respectively. The proportion of colloidal P in Yueyang soil significantly decreased by 13.37 percentage,and the proportion of dissolved P in Zhanjiang soil with long-term manure application significantly increased by 8.24 percentage points,compared with the soils without manure application. Long-term manure application remarkablely changed the content of soil water-dispersible minerals. Compared to the control group without manure application, the content of water-dispersible calcium in Daxing, Yueyang, and Zhanjiang soils increased significantly by 0.55, 1.66, and 4.15 times, respectively. The water-dispersible magnesium content also significantly increased by 0.66, 1.46, and 8.39 times in these soils. Additionally, the water-dispersible aluminum content in Daxing soil increased by 9.09%, while it decreased significantly by 19.90% and 77.27% in Yueyang and Zhanjiang soils, respectively.The results of redundancy analysis showed that soil pH,cation exchange capacity (CEC), dissolved organic carbon (DOC),and water-dispersible mineral composition (Fe/Al/Ca/Mg)were the main predictors affecting soil water-dispersible P content and morphological distribution. Long-term manure application significantly increased the water-dispersible P content of the three zonal soils and affected the P transformation,which aggravated the risk of P loss. Long-term manure application favored the particulate P and colloidal P of Yueyang and Zhanjiang soils and the particulate P of Daxing soil transformed to the dissolved P. Therefore,long-term manure application mainly affects the water dispersible P forms by changing the transformation between particulate P and dissolved P.

To explore the effects of long-term multi-cropping patterns on soil structure and organic carbon distribution in paddy fields. With fallow-rice-rice (WF-R-R) model as the control, four multi-cropping models were set up: rape-rice-ric (RP-R-R), Chinese milk vetch-rice-rice (MV-R-R), Potato-rice-rice (PO-R-R), ryegrass-rice-rice (RG-R-R). The results showed that in 5—10 cm soil layer, the contents of water-stable aggregates with size of >2 mm were increased in the multi-cropping pattern. The RG-R-R mode was 11.26 percentage points higher than the control, and the mean weight diameter (MWD) was significantly higher than the control. In 0—5 cm soil layer, the organic carbon content was increased by multi-cropping mode. The SOC content in RG-R-R mode was the highest in 0—20 cm soil layer, and the SOC content in each soil layer was increased by 9.57% (0—5 cm), 4.45% (5—10 cm) and 5.96% (10—20 cm), respectively, compared with the control. With the deepening of soil layer and the decrease of aggregate particle size, the soil organic carbon content in the multi-cropping model increased more significantly than that in the control. When the size was <0.053 mm, the soil organic carbon content in the RG-R-R model was significantly higher than that in the control. The contribution rate of soil aggregate organic carbon mainly came from the >2 mm grain size (59.03%—79.33%). In the 5—10 cm soil layer, the contribution rate of aggregate carbon in the >2 mm size of MV-R-R, PO-R-R and RG-R-R models was significantly increased by 8.5, 7.18 and 14.65 percentage points compared with the control. In conclusion, in this study, the ryegrass-rice-rice (RG-R-R) model was conducive to soil aggregate stability and organic carbon fixation in southern paddy fields.

In order to understand the characteristics and potential risks of heavy metals accumulation in farmland soils and agricultural products in typical areas of Hebei Province,soil samples (0—20 cm)and agricultural products were collected from metal smelting areas,sewage irrigation areas and vegetable areas,the contents of heavy metals Cr,Cd,Pb,As,Hg,Cu,Zn and soil pH were determined. The environmental quality of farmland soil in typical areas of Hebei Province was evaluated by the method of combining single-factor pollution index with nemerow comprehensive pollution index,the safety of agricultural products was evaluated. The results showed that the descending order of single pollution index of 7 heavy metals was Cd,Zn,Cu,As,Cr,Pb and Hg,and the single pollution index of Cd,Pb,Cu,Zn in some soil samples was more than 1.0,the environmental quality was above grade Ⅲ,and the rate of exceeding the standard of soil Cd was the highest (18.51%). Cd,Cu,Pb and Zn in the soils of the smelting area exceeded the standard,and the exceeding rate was 92.31%,69.23%,34.62% and 26.92%,respectively. The accumulation of Cd and Zn in the soil of sewage irrigation area was the most obvious,and the over-standard rate was 8.70%. The accumulation of Cd in vegetable soil was the most obvious,and the over-standard rate was 9.94%. Overall,the comprehensive pollution index of 7 heavy metals in farmland of Hebei Province was 0.64,and the soil environmental quality was in grade Ⅰ,which was clean. The soil environmental quality grades of smelting area,sewage irrigation area and vegetable area were in grade Ⅲ(light pollution),Grade Ⅰ(safety)and Grade Ⅰ(safety),respectively. According to the relevant food safety standards (NY 861—2004,GB2762—2022),the excess rates of Pb,Cd and Zn in wheat grains around the smelting area were 40.00%,40.00% and 60.00%,respectively. The excess rates of Zn,Pb and Cd in wheat grains were 57.45%,8.51% and 6.38%,respectively. The content of heavy metals in all vegetables in the vegetable area was not exceeding the standard,and the quality of vegetables is safe. Therefore,the soil environmental quality and the quality safety of agricultural products in smelting and sewage irrigation areas should be paid enough attention.

Nitrogen is an essential element for plant growth and development.It is the main limiting factor of the primary productivity of terrestrial ecosystem and has important significance for plant growth and development.Mycorrhizal fungi form a symbiotic relationship with plants,promote plants to absorb nitrogen from the soil,reduce the restriction of nitrogen on plant growth,and enhance the nitrogen exchange between soil,mycorrhizal fungi,and plants,playing an important role in the nitrogen cycle.It reviewed the utilization of different forms of nitrogen by mycorrhizal fungi,their effects on plant nitrogen metabolism,and their ecological significance on soil nitrogen cycle.Based on the current research status of mycorrhizal fungi' impact on plant nitrogen utilization,it is suggested to combine genomics,transcriptome,proteomics and environmental genomics technologies,focus on studying the nitrogen transport mechanism of mycorrhizal fungi plant symbiosis,analyze the main path of nitrogen exchange and gene interaction network between mycorrhizal fungi, plant, and soil,so as to promote plant nitrogen utilization rate,reduce nitrogen fertilizer application,and promote sustainable agricultural development.

To explore the effect of planting density on disease and quality of tobacco and the response characteristics of soil microorganisms in rainy regions,a field experiment was conducted in the Rainy Regions.The random block design was adopted to study the effects of different planting densities(CK was 16 650 and T₁ was 18 525 plants/ha) on yield of tobacco and soil microbial community structure during the experimental periods. Results suggested that:compared with the CK treatment,T1 treatment increased by 6.02% for the tobacco plant height,and 8.65% for yield,respectively. Compared with CK treatment,T1 treatment decreased by 15.38% for tobacco black shank,11.76% for tobacco black root rot,and 18.18% for tobacco anthracnose at the mature stage,respectively. T1 treatment increased by 1.62%for the species diversity and decreased by 0.99% for the richness of the rhizosphere soil bacterial community,increased by 3.76% for the species richness and decreased by 4.71% for the diversity of the fungal community when compared with CK treatment. The bacterial and fungal community structure of the T1 treatment was similar to that of the CK treatment,but the microbial dominant taxa in the soil samples was inconsistent. In the horizontal structure of phylum,T1 treatment relative abundance of bacteria in the soil Proteobacter,Acidobacteria and Actinobacteria,and fungal in the soil Ascomycota was higher. In the horizontal structure of genera,T1 treatment relative abundance of bacteria Sphingomonas and fungi Penicillium was significantly improved. Redundancy analysis (RDA)showed that environmental factors (sunshine duration,rainfall,and temperature)significantly affected the bacterial and fungal community structure,and the influence of soil bacterial community was rainfall>temperature>sunshine duration,the influence of soil fungal community was sunshine duration>rainfall>temperature,respectively. This study indicated that properly increasing the planting density of flue-cured tobacco in rainy regions could improve the soil microenvironment,and reduce tobacco diseases,which could improve the quality of flue-cured tobacco and increase the income of tobacco farmers.

In order to explore the effects of straw and microbial fertilizer on the salt content of soil and crops in saline-alkali soil,the experiment was conducted in Dalat Banner,Inner Mongolia.Four treatments were set up:no straw and no microbial fertilizer(CK),single application of straw(G),single application of microbial fertilizer(F)and combined application of straw and microbial fertilizer(GF).Four crops,oat,sorghum hybrid sudangrass,proso millet and oil sunflower,were planted,respectively.The effects of straw and microbial fertilizer on salt ion concentration and salt content of soil and crops in saline-alkali soil were analyzed.The results showed that compared with CK,straw combined with microbial fertilizer could significantly reduce soil salt content,increase crop biomass and salt ion accumulation in crops,and the soil total salt content in the soil planted with oil sunflower was the lowest at 4 400.41 mg/kg,which was significantly reduced by 13.85% compared with CK.Crop biomass and salt ion accumulation of sorghum hybrid sudangrass treated with straw combined with microbial fertilizer were the largest,and the biomass and salt ion accumulation were increased by 68.32% and 108.28% compared with CK,respectively.In addition,straw combined with microbial fertilizer enhanced the selective absorption ability of each crop for salt ions.Under combined treatment,oat had stronger absorption ability for Mg²⁺,Cl^- and {{\mathrm{SO}}_4}^{2-},which were 50.51%,72.74% and 56.39% higher than CK,respectively.The selective absorption capacity of Ca²⁺ was 76.01% higher than that of CK.Oil sunflower mainly absorbed K⁺,and its content was 12.90% higher than CK.In conclusion,straw combined with microbial fertilizer could significantly improve crop biomass,salt ion accumulation and salt ion selective absorption ability,and could effectively reduce the total salt content of saline-alkali soil.Among the 4 crops,sorghum hybrid sudangrass and oil sunflower perform better.

In order to control the amount of organic manure in the greenhouse vegetable management system,reduce the load of nitrogen and phosphorus in the greenhouse soil and reduce the risk of non-point source pollution of nitrogen and phosphorus in the greenhouse vegetable,a 3-year field experiment,was conducted,and a total of 5 treatments were set.They were the farmers' traditional amount of organic manure in this study area(FP,i.e.the control treatment),the amount of 50% of farmers' traditional amount of organic manure(FP-M,i.e organic manure reduction treatment),and catch crop planted in the fallow period on the basis of the FP-M treatment with forage maize,forage sorghum and legumes incorporation(FP-M+C,FP-M+S and FP-M+L,respectively).In FP-M+C,FP-M+S and FP-M+L treatment,the straw was returned in situ before vegetable transplanting.The leaching liquor was collected in situ,and nitrogen and phosphorus leaching amount,soil organic matter, {{\mathrm{NO}}_3}^{-}-N,Olsen-P and vegetable yield were measured,to study the effect of substitution of catch crops for organic manure during the fallow period.The results showed that,there was no difference in vegetable yield between FP treatment and FP-M,FP-M+C,FP-M+S and FP-M+L treatment.However,FP-M+C and FP-M+S treatments had significantly higher organic matter content in 0—40 cm soil compare to FP treatment.Compared with FP treatment,the leaching amount of total nitrogen in the FP-M,FP-M+C,FP-M+S and FP-M+L treatment showed a significant decrease in the fallow period,and decreased by as much as 13.9%,59.5%,65.4% and 54.5%,respectively;in the vegetable growing period,and decreased by as much as 38.3%,48.5%,39.0% and 24.0%,respectively.Compared with FP treatment,the leaching amount of total phosphorus in the FP-M,FP-M+C,FP-M+S and FP-M+L treatment showed a significant decrease in the fallow period,and decreased by as much as 42.3%,53.9%,45.4% and 49.1%,respectively;in the vegetable growing period,and decreased by as much as 37.7%,33.8%,27.7% and 26.3%,respectively.The {{\mathrm{NO}}_3}^{-}-N and Olsen-P contents soil profile of the FP-M,FP-M+C,FP-M+S and FP-M+L treatments were significantly decreased compared with FP treatment,in 80—200 cm and 20—80 cm,respectively.Therefore,that reducing 50% of the organic manure by farmers' practice and planting catch crops in the fallow period and returning the straw in situ before vegetable transplanting can increase organic matter content in 0—40 cm soil in the study area.Obviously,the organic manure can be substituted with catch crops.It reduces the risk of nitrogen and phosphorus pollution in greenhouse vegetable while decreasing nitrogen and phosphorus leaching.

To express the protein StSPS1 encoding potato sucrose phosphate synthase(SPS)in E.coli and prepare polyclonal antibodies.The StSPS1 gene was cloned from the tubers of tetraploid potato variety Chuanyu 10,with a total coding region of 3 165 bp and a protein length of 1 055 aa.Subsequently,based on the constructed His tag fusion expression vector PET30a-StSPS1,the protein induction,denaturation,purification,renaturation,and rabbit immune tests of StSPS1 protein were carried out.The results showed that the molecular weight of StSPS1 protein was approximately 119.62 ku,and its expression was minimal in soluble supernatant,mainly in insoluble precipitates.The optimal induction conditions were induced with 0.5 or 1.0 mmol/L IPTG at 37 ℃ for 4 h.Due to StSPS1 being an inclusion body protein,it was subjected to inclusion body denaturation and purified using His tags to match the size of the target band.At the same time,a protein immunoblotting(WB)test was performed using His antibodies,and the target band was detected at 119.62 ku,indicating the successful purification of StSPS1 inclusion body protein.Finally,by injecting the dialyzed and refolded StSPS1 protein into the subcutaneous tissue of rabbits,two antibodies against StSPS1 were successfully immunized.After WB identification,it was found that both antibodies could hybridize target bands in the antigen and the total protein of leaves in Chuanyu 10.In summary,potato StSPS1 protein was induced and purified,and rabbit polyclonal antibodies against StSPS1 protein were successfully prepared.

In order to provide a theoretical basis for rational application of organic fertilizers and ensure the healthy development of soil ecosystems in corn fields,the effects of soil fungal communities under different levels of organic fertilizer application for the composition,diversity,and functional characteristic were studied.In the meantime,a field experiment was used,with a total of 4 treatments were set up,and the high-throughput sequencing and FUNGuild method were used to analyze the soil fungal diversity,community structure and functional groups in different fertilization rates.The results showed that the increased application of organic fertilizer could increase the content of soil organic matter,available phosphorus,available potassium,urease,catalase,etc.,and it was positively correlated with the application amount of organic fertilizer.Applied organic fertilizers could increase the diversity of soil fungal communities and reduce their richness.The dominant fungal communities in the soil under different fertilization rates were Ascomycota,Mortierellomycota,Basidiomycota,and Olpidiomycota,the relative abundance of Ascomycota and Basidiomycota was significantly higher in the treatment with a medium amount of cattle manure than in the control without organic fertilizer;from the perspective of fungal genera,the dominant genera include Fusarium,Humicola,Olpidium,and Microidium.The application of organic fertilizer increased the relative abundance of symbiotic and saprophytic nutrients,and with the increase of organic fertilizer application,the abundance of pathological nutrients showed a decreasing trend;the number of woody saprophytic fungi in the treatment with increased organic fertilizer application was significantly higher than that in the treatment without organic fertilizer application,while the number of plant and animal pathogens was lower than the control.Therefore,it is believed that increasing a certain amount of organic fertilizer application could optimize the soil microbial environment and promote the increase of corn plant yield.

This research studied the effects of different phosphorus and potassium fertilization methods on maize growth,nutrient uptake and utilization.It was determined suitable fertigation timings and frequencies of phosphorus and potassium fertilizer,and to provide a theoretical basis for drip fertilization technology of maize with phosphorus and potassium in semi-arid areas of northeast China.A field experiment was conducted in 2018—2019,with Xiangyu 998 as a test material,six treatments were set up,P0 (No phosphorus fertilizer),K0 (No potassium fertilizer),P1(100% basal application of P fertilizer,50% basal application of K fertilizer,the other 50% fertigation three times),K1(100% basal application of K fertilizer,50% basal application of P fertilizer,the other 50% fertigation four times),P1K1(100% basal application of P and K fertilizer),and P4K3(50% basal application of P and K fertilizer,the other 50% P fertigation four times and the other 50% K fertigation three times).The results showed that compared with the P1 treatment,the P4K3 treatment increased maize yield by 4.2%,dry matter accumulation at maturity by 6.8% (P<0.05),post silking P accumulation by 33.3% (P<0.05),and significantly improved the P fertilizer recovery efficiency and agronomic efficiency by 21.6 percentage points and 28.5%,respectively.Compared with the K1 treatment,the P4K3 treatment increased maize yield by 3.5%,dry matter accumulation at maturity by 5.1%,and significantly improved the K fertilizer recovery efficiency and agronomic efficiency by 14.9 percentage points and 53.5%,respectively;compared with the single application of phosphorus and potassium treatment,maize yield was increased by 5.0%,the uptake of phosphorus after silking was increased by 26.3%,and P fertilizer recovery efficiency and P agronomic efficiency were increased by 19.5 percentage points and 32.6%,respectively;K fertilizer recovery efficiency and agronomic efficiency increased by 15.2 percentage points and 95.5%,respectively.Fractional fertigation of phosphorus and potassium fertilizer could not only be beneficial to improve yield of maize,but also promote post-silking nutrient uptake and improve nutrient utilization under drip irrigation conditions.Comprehensive consideration,P4K3 treatment is a more suitable drip fertigation technique for field production.

In order to explore the law of nitrogen absorption,transport and utilization of sesame at seedling stage,two sesame varieties with different nitrogen efficiency,including Zhengzhi HL05(ZZ,high efficiency)and Myanmar high yielder(MD,nitrogen inefficiency)were used as materials.The differences in root morphology,nitrogen absorption,transportation and utilization,nitrogen metabolism indices and related gene expressions involved were compared between the two accessions through hydroponics,under normal nitrogen(CK,17.86 mmol/L)and low nitrogen(LN,0.2 mmol/L)levels respectively.The results showed that under different nitrogen concentrations,the root morphological indexes,biomass,nitrogen accumulation,enzyme activities related to nitrogen metabolism and root nitrogen use efficiency of ZZ variety were higher than those of MD on the whole.Low nitrogen stress significantly decreased the biomass,nitrogen accumulation,and leaf nitrogen metabolism-related enzyme activities,increased root morphological indexes,root activity,root-shoot ratio,nitrogen physiological use efficiency,root dry matter use efficiency and nitrogen use efficiency.Among them,the biomass,nitrogen accumulation,transport coefficient,root nitrogen physiological use efficiency and nitrogen use efficiency of ZZ were 2.48,1.08,1.73,2.36 and 2.65 folds of MD,respectively.qRT-PCR results showed that under low nitrogen stress,SiNPF6.3a/b,SiNPF4.6a,SiNRT2.4a/b,SiNRT2.5,SiNPF7.3a/b and SiNPF2.13 genes involved in {{\mathrm{NO}}_3}^{-} absorption,transport and redistribution of the nitrogen efficient variety ZZ in leaves were up-regulated,and the gene expression levels were higher than those of the nitrogen inefficient variety MD.In Conclusion,under low nitrogen stress,nitrogen efficient sesame varieties had more developed roots and higher ability of nitrogen assimilation,transport and redistribution at seedling stage,so as to obtain higher nitrogen accumulation and nitrogen use efficiency.

By investigating the effects of chemical fertilizer reduction with humic acid bio-fertilizer on the carbon and nitrogen metabolic processes of kidney bean leaves,it provides a theoretical basis for the application of humic acid fertilizer for kidney beans in Northeast China.This trial was conducted at the Anda Experimental Base of Bayi Agricultural Reclamation University in Heilongjiang,using the kidney bean variety Baisak as the test material for two years of field trials in 2021 and 2022.There were six treatments:CF(conventional fertilizer application),RF(fertilizer reduction of 20%),RFH1(fertilizer reduction of 20%+45.0 kg/ha humic acid bio-fertilizer),RFH2(fertilizer reduction of 20%+67.5 kg/ha humic acid bio-fertilizer),RFH3(fertilizer reduction of 20%+90.0 kg/ha humic acid bio-fertilizer),RFH4(fertilizer reduction of 20%+112.5 kg/ha humic acid bio-fertilizer).The experiment was conducted to determine the indicators of carbon and nitrogen metabolism and their products throughout the reproductive period of kidney bean,and to determine the yield of kidney bean and its constituent factors at the harvesting stage.The activities of sucrose synthase(SS),sucrose phosphate synthase(SPS),acidic invertase(AI),neutral invertase(NI)in carbon metabolism and nitrate reductase(NR),nitrite reductase(NiR),glutamate synthase(GOGAT)and glutamine synthetase(GS)in nitrogen metabolism were analyzed by fertilizer reduction with humic acid bio-fertilizer,and the activities of carbon and nitrogen metabolites sucrose,soluble sugar,starch and soluble protein.To determine the effect of humic acid on the carbon and nitrogen metabolism of kidney bean.The results showed that the application of humic acid bio-fertilizer increased the activity of enzymes related to carbon and nitrogen metabolism in kidney bean leaves,increased the content of carbon and nitrogen metabolites and improved the yield of kidney bean compared with CF treatment.During the reproductive period,SS activity of RFH2 treatment was significantly increased by 9.5%—15.8% compared to CF treatment.RFH3 treatment significantly increased the SPS activity by 16.5%—38.1% compared to CF treatment.The AI activity of RFH3 treatment was significantly increased by 10.8%—25.5% compared to CF treatment.RFH2 treatment increased NI activity by 14.0%—32.1%.With the application of humic acid bio-fertilizer,NR and NiR activities were significantly increased by 22.6%—50.1% and 16.3%—19.8%,and GOGAT activities were significantly increased by 16.0%—35.7% in the RFH2 treatment compared to the CF treatment.RFH3 treatment significantly increased the GS activity by 14.5%—44.1% compared to CF treatment.Meanwhile,among the treatments with humic acid bio-fertilizer,RFH2 treatment significantly increased the carbon and nitrogen metabolites sucrose,soluble sugar,starch and soluble protein in kidney bean leaves by 7.6%—9.3%,14.1%—26.8%,6.7%—10.5% and 3.7%—8.8%,respectively and the starch content significanthy increased by 0.8—1.3 percentage points.In addition,the application of humic acid bio-fertilizer was able to increase the yield of kidney bean,with a significant increase of 24.8%(2021)and 21.5%(2022)in the RFH2 treatment compared to the CF treatment.The treatment of 20% reduction in conventional chemical fertilizer application with 67.5 kg/ha of humic acid bio-fertilizer(RFH2)could increase the activity of enzymes related to carbon and nitrogen metabolism in kidney bean leaves,increase the accumulation of carbon and nitrogen metabolites in leaves,and increase the yield of kidney bean.

Conservation tillage and organic fertilizer application are one of the effective solutions to alleviate ecological vulnerability in dry farming areas of the Loess Plateau.Reasonable tillage and fertilization measures are of great significance for the realization of two crops a year in the arid area of central Shanxi.The dry farmland in the Loess Plateau was taken as the research object,and the split-plot experimental design was adopted,the main area was three tillage methods (deep tillage (DT),deep loosening (SS),no tillage (NT)),and the sub-area was four fertilization levels (No fertilizer control (CK),full chemical fertilizer (CF),50% chemical fertilizer+50% organic fertilizer (OF),full organic fertilizer (OM)).The changes of soil bulk density,available nutrients and annual yield of wheat and maize under different tillage and fertilization methods were explored.The results showed that in 0-20 cm the soil bulk density of SS and NT treatments were lower than that of DT treatment after organic fertilizer application.The soil bulk density of SS+OF treatment was 1.13 g/cm³,which was significantly lower than that of DT+OF treatment in wheat season.In the whole annual rotation system,the soil mass water content of NT+OM treatment was the highest,which was 7.88 percent point higher than that of other fertilization treatments,and the three-phase ratio of soil under SS+OM treatment was more ideal,and the deviation value of three phase was low.Under the three tillage methods,the content of available nitrogen and available phosphorus generally showed the trend of OM>OF>CF>CK,and the content of available potassium was significantly related to the fertilization method,which was the highest under the CF treatment.The application of organic manure in maize season significantly increased the fresh ear yield of maize compared with a single application of chemical fertilizer,but the difference between them was not significant.The annual yield of wheat and maize under SS+OM treatment was the highest,reaching 19 145 kg/ha.In summary,under the conditions of this experiment,the combination of SS,NT and organic fertilizer application could significantly improve the physical properties of the soil,and the content of alkali-hydrolyzable nitrogen and available phosphorus also had a certain degree of improvement,and SS+OM treatment was beneficial to the increase of the yield of wheat-maize continuous cropping field in the Loess Plateau.

In order to determine the suitable sowing date of green manure for multiple cropping rape in Hetao irrigation area,field experiments were carried out in Hangjinhou Banner,Bayannur City,Inner Mongolia Autonomous Region in 2019 and Dalad Banner,Ordos City in 2022.There were five sowing dates in Hangjinhou Banner experimental site from July 26th to August 15th,2019,and one sowing date was set every five days,which were sown on July 26th,July 31st,August 5th,August 10th and August 15th,respectively.Similarly,from July 22nd to August 11th,2022,the experimental site in Dalad Banner was set up with five sowing dates,and one sowing date was set every five days to study the effects of different sowing dates on the green manure biomass,nutrient content and nutrient accumulation of rape.The results showed that although the biomass level and climate conditions of the two experimental sites were different,the overall trend showed a decline with the delay of sowing date.Compared with the first sowing stage,the rape biomass in the fifth sowing stage decreased by 90.3% and 75.4% respectively,and the average active accumulated temperature,effective accumulated temperature and sunshine hours in the two-point growth period decreased by 469.9 ℃,409.9 ℃ and 179.1 h,respectively.At the same time,when sowing in the first,second and third stages,compared with the nutrient input (N 27.3 kg/ha,P₂O₅ 34.5 kg/ha),the nutrient input of rape was higher than the input,and the amount of carbon and potassium returned to the field was at least C1 800 kg/ha and K₂O 200 kg/ha.Therefore,considering the biomass of rape green manure and the amount of nutrients returned to the field,rape could be sown early after wheat harvest in Hetao irrigation area,making full use of light and temperature resources to promote rape growth and nutrient accumulation.In order to achieve more than 5 t/ha of rape returning to the field and obtain a higher amount of nutrients returning to the field,at least 1 300 ℃ of active accumulated temperature,1 100 ℃ of effective accumulated temperature and 640 h of effective sunshine hours should be accepted during the rape growth period.

In order to improve the use effect of ordinary stable urea fertilizer,develop biostimulant and biochemical inhibitor combined high-efficiency,stable and synergistic urea fertilizer.A field pot test was carried out to investigate the effect of urea fertilizer with the biological stimulator Enteromorpha polysaccharide and various biological inhibitors on rice cultivation in black soil.The control group in the experiment consisted of no nitrogen fertilizer (CK) and only urea fertilizer(N).In the treatment group, urea was supplemented with Enteromorpha polysaccharide (E), the biochemical inhibitor N-butyl thiophosphate triamine (NBPT), 3,4-dimethylpyrazole phosphate (DMPP), and 2-chloro-6-trimethylpyridine (CP). Additionally, a combination of Enteromorpha polysaccharide and a biochemical inhibitor was also added to urea. Nine treatments were set up to study the nitrogen conversion characteristics,physiological and developmental biological indexes of rice,nitrogen uptake by plants,and efficiency of nitrogen absorption and utilization from fertilizers.When urea was applied alone,the addition of Enteromorpha polysaccharide reduced ammonia volatilization loss in black soil,significantly increased ammonium nitrogen content in soil at the tillering stage,promoted plant growth,and then significantly increased grain yield and nitrogen use efficiency.The combination of Enteromorpha polysaccharide and NBPT significantly increased ammonium nitrogen content in black soil,but the application of Enteromorpha polysaccharide promoted the decomposition of NBPT,resulting in no significant effect on rice yield and nitrogen use efficiency.In black soil cultivation rice,the combination of Enteromorpha prolifera polysaccharide and DMPP significantly reduced rice grain yield and nitrogen use efficiency,and the application of stable urea fertilizer combined with both was not conducive to yield increase and efficiency increase.The combination of tillering stage CP rice plants and Enteromorpha polysaccharides had the highest ammonium nitrogen content in black soil,and had a synergistic effect on the process of inhibiting urea nitrogen conversion to nitrate nitrogen.The apparent nitrification rate of black soil treated with the two was significantly lower than that of CP alone,while the increase in ammonium nitrogen promoted rice tillering,increased panicle percentage,and thus significantly increased rice grain yield.

To explore the influence of straw returning years to the field after deep turning back on soil bacterial community in continuous cropping corn fields in the West Liaohe Plain,and provide theoretical guidance for continuous straw returning to improve soil fertility.This study takes corn straw leaving the field as a control (CK),based on the high-throughput sequencing technology of bacterial 16S rDNA V3-V4 region,combined with bioinformatics,we analyzed the characteristics of organic matter,nitrogen nutrients content,soil bacterial community structure and diversity changes in 0-20 cm and 20-40 cm soil layers of corn fields with continuous straw returning for 2(SR2),5(SR5) and 10 a (SR10).The results showed that SR2 had no significant difference with CK in soil organic matter and nitrogen nutrients content,while SR5 and SR10 significantly increased soil organic matter and nitrogen nutrient content;under different straw returning years,soil bacterial diversity was different and each had its own unique OTU,among which SR10 OTU had the largest number;alpha diversity index showed that the relative abundance and diversity of soil bacterial community were not significantly different between SR2 and CK,SR5 and SR10 increased significantly,and SR10 and CK had the largest difference;a total of 51 bacterial groups were obtained at the phyla level,including Actinobacteriota,Proteobacteria,Acidobacteriota,Crenarchaeota and Chloroflexi,whose relative abundance was more than 5%.The relative abundance of Proteobacteria,Acidobacteriota and Chloroflexi increased with the increase of returning years.RDA clustering analysis showed that the soil bacterial community structure of 0-20 cm soil layer SR2 was similar to CK,SR5 was more similar to SR10,20-40 cm soil layer,different straw returning years,treatments were different from CK,SR2 and SR5 were similar,SR10 had significant differences in community structure compared to SR5 and SR2.The contents of soil {\mathrm{NO}}_3^{-}-N, {\mathrm{NH}}_4^{+}-N,OM,and TN all had effects on bacterial flora,and they were soil {\mathrm{NO}}_3^{-}-N> {\mathrm{NH}}_4^{+}-N>OM>TN.The contents of soil organic matter and nitrogen nutrient had no significant difference between continuous straw returning for 2 a and CK,while continuous straw returning for 5 and 10 a were significantly increased.In summary,the microbial diversity and richness of bacteria showed minimal changes in the soil layers of 0-20 cm and 20-40 cm after continuous straws returning for 2 a.After continuous straws returning for 5 and 10 a,both soil layers significantly increased;the bacterial community structure continuous straw returning for 2 a was similar to CK in the 0-20 cm soil layer,while the bacterial community structure continuous straw returning for 2,5,10 a were changed in the 20-40 cm soil layer.

To explore the effects of long-term different fertilization on soil microbial biomass carbon,nitrogen and enzyme activity of double cropping maize in Southern China.Based on a 35 a long-term located experiment in dryland red soil in Jinxian,Jiangxi Province,four treatments including no fertilizer(CK),chemical fertilizer(NPK),chemical fertilizer and fresh pig manure(NPKM),and fresh pig manure(OM).The soil nutrients,microbial biomass carbon,nitrogen and enzyme activities were measured in the 0—20 cm,20—40 cm soil layers at the maturity of double cropping maize and the correlations between them were analyzed.Results showed that long-term fertilization(NPK,NPKM and OM)significantly increased soil microbial biomass carbon,nitrogen and enzyme activity.During the spring maize period,the soil microbial biomass carbon and nitrogen content of fertilization treatment compared with CK increased by 67.05%—159.15% and 3.33%—62.37% in the 0—40 cm soil layer.And the activities of catalase,phosphomonoesterase,urease and sucrase increased by 0.22%—79.71%,9.82%—59.51%,8.73%—82.37%,66.67%—538.89%,respectively.During the autumn maize period,the soil microbial biomass carbon and nitrogen content of fertilization treatment compared with CK increased by 36.30%—136.72% and 17.09%—47.29% in the 0—40 cm soil layer.And the activities of catalase,phosphomonoesterase,urease and sucrase increased by 7.41%—74.55%,22.69%—57.39%,18.85%—58.98% and 51.70%—216.67%,respectively.Among them,the NPKM treatment had the best improvement effect.In general,soil microbial biomass carbon,nitrogen and enzyme activity in 0—20 cm soil layer were higher than in 20—40 cm soil layer,and the soil microbial biomass carbon,nitrogen and enzyme activity in autumn maize period were higher than those in spring maize period.NPKM and OM treatments also significantly increased soil pH,organic carbon,total nitrogen,total phosphorus,total potassium,available phosphorus,available nitrogen and available potassium.After long-term application of organic fertilizer,soil phosphorus accumulation was obvious,while NPK treatment accelerated soil acidification.All treatments could significantly increase maize yield(P<0.05). Compared with CK, it increased by 1.04—15.07 times. In conclusion,organic-inorganic application(NPKM)is the best fertilization measure to enhance soil nutrients,microbial biomass,enzyme activity and yield.

In order to study the differences in yield,accumulation and utilization of nitrogen (N),phosphorus (P) and potassium (K)among wheat varieties from different geographical origins and among high and low yield wheat varieties from the same geographical origin in dryland farming, 165 varieties from China(58),the International Maize and Wheat Improvement Center(CIMMYT,42)and others abroad (65)were planted in the farm of Henan University of Science and Technology in Luoyang,Henan Province, to analyze the yield and its components,the characteristics of accumulation,distribution and requirement at maturity of N,P,K.Compared with others abroad,the grain yield,grains per spike,1000-grain weight,N,P and K physiological efficiency of CIMMYT varieties were significantly increased by 21.3%,39.1%,26.4%,33.2%,22.6% and 36.1%,respectively,while those of Chinese varieties were increased by 10.5%,18.1%,24.3%,29.4%, 12.1% and 24.3%,respectively,however,the spike number,the N,P and K accumulation in stem and leaf,the N,P,K and dry matter requirements of 100 kg grains of CIMMYT and Chinese varieties decreased significantly,moreover,the increase and decrease of CIMMYT varieties were higher than those of Chinese varieties.Compared the low-yield varieties from the same geographical origin,the yield,spike number,grain number per spike and biomass of Chinese high-yield varieties were significantly increased by 122.4%,38.7%,39.3% and 96.1%,respectively;the yield,spike number and biomass of CIMMYT high-yield varieties were significantly increased by 97.6%,68.2% and 71.7%;the yield,spike number,grain number per spike,1000-grain weight and biomass of high-yield varieties of others abroad were significantly increased by 157.2%,33.0%,43.6%,35.9% and 76.4%.For Chinese varieties,compared with the low-yield varieties, the shoot and grain N,P,K accumulations of high-yield varieties were significantly increased by 98.8%,101.0%,83.7% and 118.8%,104.7%,131.2%,as well as the N,P,K uptake efficiencies were significantly increased by 93.6%,84.6% and 70.3%,the nutrient requirements for grain N,P,K content formation were significantly increased by 102.8%,109.5% and 75.9%,but the K and dry matter requirements for 100 kg grains formation were significantly decreased by 16.8% and 11.1% respectively.For CIMMYT varieties,compared with the low-yield varieties, the N,P,K uptake efficiencies in high-yield varieties were significantly increased by 68.5%,71.4% and 63.6%,as well as the nutrient requirements for grain N,P,K content formation were significantly increased by 79.2%,81.7% and 76.5%,while the N and P requirements for 100 kg grains were significantly decreased by 10.7% and 10.3%,respectively.For others abroad,compared with the low-yield varieties, the N,P, K physiological efficiencies in high-yield varieties were increased significantly by 34.7%,30.2% and 60.6%, as well as the nutrient requirements for grain N,P,K content formation were increased significantly by 73.0%,110.8% and 52.1%,while the N,P,K and dry matter requirements for 100 kg grains were significantly decreased by 26.7%,23.6%,36.8% and 24.7%,respectively.To sum up,many characteristics of grain formation and N,P,K absorption and utilization in wheat showed significant differences among different geographical origin varieties.CIMMYT varieties had higher grain number per spike,1000-grain weight,harvest index,grain N accumulation,and P,K physiological efficiency,while others abroad had higher spike numbers,N,P,K accumulation in stem and leaf,N,K accumulation in shoot and uptake efficiency,dry matter and N,P,K requirements for 100 kg grains,and the values of most indexes of Chinese varieties were between CIMMYT varieties and others abroad.Compared with low-yield varieties,high-yield varieties from the same geographical origin had the ability to improve yield components,harvest index and nutrient uptake efficiency,while increased the nutrient requirements for grain N,P,K content formation.Therefore,the N,P,K input should be increased appropriately in the production system which aimed to high yield and high nutrient content.

In order to clarify the influence mechanism of total replacement of chemical fertilizer with organic fertilizer on the nitrogen fertility of tea garden soil.Based on the 5 a experiment of replacing chemical fertilizer with organic fertilizer in tea garden,single application of chemical fertilizer(CF)and full application of organic fertilizer(OF)were selected as treatments,the effects of total replacement of organic fertilizer with chemical fertilizer on the physical and chemical properties,mechanical stability,aggregate composition,and aggregate inorganic nitrogen distribution characteristics of tea garden soil in rainy and dry seasons were studied,and the influencing factors of aggregate inorganic nitrogen distribution were analyzed.The results showed that:Compared with CF treatment,OF treatment increased the pH value,organic matter content and total nitrogen content of surface soil in rainy and dry seasons.However,there was no significant difference in soil pH between the two treatments in the rainy season(P>0.05);in the rainy season,the cation exchange capacity,ammonium nitrogen content and nitrate nitrogen content in the surface soil of the tea garden under the OF treatment were lower or significantly lower(P<0.05)than those under the CF treatment,while in the dry season,the OF treatment was significantly higher than that under the CF treatment(P<0.05),with an increase of 27.02%, 58.97%, and 266.84%, respectively. Different treatments had significant effects on the mass percentage of 0.25—2.00 mm and<0.25 mm aggregates and GWD;compared with CF treatment, OF treatment increased the mass percentage of 0.25—2.00 mm aggregates and GWD, and decreased the mass percentage of<0.25 mm aggregates; seasons had a significant effect on the mass percentage of aggregates<0.25 mm (P<0.05).The contents of ammonium nitrogen and nitrate nitrogen in aggregates of different treatments were as follows:<0.25 mm aggregates were the highest,0.25—2.00 mm aggregates were the second,and>2.00 mm aggregates were the lowest;in rainy season,the content of ammonium nitrogen and nitrate nitrogen in aggregates at all levels of OF treatment was lower or significantly lower(P<0.05) than that of CF treatment,while in dry season,OF treatment was significantly higher than that of CF treatment(P<0.05);compared with the rainy season,the content of ammonium nitrogen and nitrate nitrogen in aggregates at all levels under CF treatment was significantly reduced in dry season(P<0.05),and the content of ammonium nitrogen and nitrate nitrogen in aggregates at all levels under OF treatment was increased or significantly increased in dry season(P<0.05);under different treatments,the proportion of ammonium nitrogen and nitrate nitrogen storage of aggregates showed that 0.25—2.00 mm aggregates were the highest(51.70% and 51.14%),>2.00 mm aggregates were the second(34.59% and 35.51%),and<0.25 mm aggregates were the lowest(13.71% and 13.34%);compared with CF treatment,OF treatment significantly reduced the proportion of<0.25 mm aggregate ammonium nitrogen storage in rainy and dry season and the proportion of <0.25 mm aggregate nitrate nitrogen storage in dry season(P<0.05),and significantly increased the proportion of 0.25—2.00 mm aggregate ammonium nitrogen storage in rainy season and 0.25—2.00 mm aggregate nitrate nitrogen storage in dry season(P<0.05).Correlation analysis showed that the content of ammonium nitrogen in soil aggregates was mainly affected by soil pH,cation exchange capacity and total nitrogen content,while the content of nitrate nitrogen in soil aggregates in tea garden was mainly affected by soil pH,organic matter content and total nitrogen content;further RDA analysis showed that soil pH and cation exchange capacity were the main factors affecting the distribution of inorganic nitrogen in soil mechanically stable aggregates.To sum up,total replacement of chemical fertilizer with organic fertilizer in tea garden is beneficial to improve the content of soil organic matter,coordinate the supply of soil nitrogen in rainy and dry seasons,and promote the formation of large aggregates and the accumulation of soil inorganic nitrogen.

Based on the long-term improvement experiment of organic fertilizer of soda saline-alkali soil in Songnen Plain,the effects of different improvement years(4,11,15,20 a)on soil colloid components,soil organic carbon components and soil organic-mineral compound degree were studied with no improvement as the control(CK).The results showed that with the increase of improvement years,the colloidal content of soil water dispersive group(G₀)decreased significantly(P<0.05),while that of soil calcium-binding complex(G₁)increased significantly(P<0.05);there were no significant changes in colloid content of soil iron and aluminum oxide binding complex(G₂)and(G₀+G₁+G₂)content of different treatments;the organic carbon content in G₀ group,G₁ group and G₂ group showed an increasing trend.Organic carbon content and heavy fraction organic carbon content of all organic fertilizer treatments were significantly increased compared with CK(P<0.05).In all treatments,organic carbon content in 4 a treatment was the highest,and heavy fraction organic carbon content in 11 a treatment was the highest.The total contribution rate of soil carbon sequestration of the treatments complexes with improved years of 11 a or more was 35.51%—54.64%.Compared with CK,organic-mineral compound degree of soda saline-alkali soil treated with organic fertilizer increased to varying degrees,and the increase was obvious in the treatment of 11 a and above.In conclusion,the long-term application of organic fertilizer promoted the transformation of water dispersive colloid of soda saline-alkali soil to water stable complex,significantly increased the contribution rate of the complex to soil carbon fixation,and significantly improved the degree of organic-mineral composition of the soil.

In order to select a reasonable fertilization pattern suitable for high-yielding and high-quality production of rice stubble weakly glutenous wheat,this experiment was conducted with weakly glutenous wheat Ningmai 13 and Wanximai 0638 as the test varieties,with no fertilization(CK),conventional fertilization of compound fertilizer+urea(T1),slow-release blended fertilizer(T2),loss-control fertilizer(T3),humic acid compound fertilizer(T4),and wheat formula fertilizer(T5),under the same conditions of nutrient supply,the effects on dry matter distribution and transport,filling,yield and quality of weakly glutenous wheat were analyzed.The results showed that slow-release blended fertilizer and wheat formula significantly increased the post-flowering dry matter production,and increased wheat grain filling rate,effective filling days,and grain weight compared with conventional fertilizer application.The grain yield increased by 9.27%—24.30% and 11.64%—22.98% respectively compared with conventional fertilizer.Slow-release blended fertilizer 2 years two varieties than conventional fertilization treatment of nitrogen fertilizer agronomic efficiency increased by an average of 23.14%, 36.88%, wheat formula fertilizer two years two varieties than conventional fertilization increased by an average of 36.31%, 39.35%. Wheat formula fertilizer treatment of two wheat varieties for testing grain quality had reached the national standard of weak gluten wheat. In summary,wheat formula fertilizer can be used as one of the fertilization patterns for high-yielding and high-quality production of rice stubble weak-gluten wheat in the test area,or appropriately reduce the application amount of slow-release blended fertilizer as the fertilization pattern for high-yielding and high-quality production of rice stubble weak-gluten wheat.

In order to explore the effects of irrigation method and topdressing nitrogen on grain yield,quality and nitrogen accumulation and translocation of furrow-seeding wheat in dryland,a field experiment including five treatments,i.e.no irrigation and no topdressing nitrogen(NIND),every furrow irrigation and no topdressing nitrogen(EFIND),alternative furrow irrigation and no topdressing nitrogen(AFIND),every furrow irrigation and topdressing nitrogen(EFITD)and alternative furrow irrigation and topdressing nitrogen(AFITD),were set at jointing stage based on a no-tillage furrow-seeding wheat field from October 2019 to June 2020.The grain yield and its components,main quality index,as well as the shoot nitrogen accumulation,translocation and distribution were measured.The results showed that irrigation at jointing stage,irrigation mode and topdressing nitrogen significantly regulated the yield,quality and nitrogen accumulation and translocation of furrow-seeding wheat in dryland,and the regulation effects was additive.Compared with NIND,the grain yields in EFIND,AFIND,EFITD and AFITD were significantly increased by 46.57%,67.72%,83.71%,95.88%,as well as the nitrogen accumulation at anthesis,the post-anthesis nitrogen accumulation and its contribution rate to grain were significantly increased,so the nitrogen accumulation amounts at maturity were significantly increased by 25.94%,41.00%,65.86%,82.64%.Compared with NIND,the quality in EFIND,AFIND and EFITD was significantly decreased,while that in AFITD did not decrease or even significantly increased.Compared with EFI,AFI did not affect the nitrogen accumulation at anthesis,but significantly increased the post-anthesis nitrogen accumulation,and thus significantly increased the total nitrogen accumulation at maturity and grain nitrogen accumulation.Finally,compared with EFI,the grain yield in AFI was significantly increased,but the difference of quality indexes except the sedimentation value was not significant under ND,while the significant improvement of grain yield and various quality indexes was observed under TD.Compared with ND,the nitrogen accumulation at anthesis,pre-anthesis nitrogen accumulation and its translocation amount,post-anthesis nitrogen accumulation and its contribution rate to grain in TD were significantly increased,and thus the shoot nitrogen accumulation and grain nitrogen distribution rate at maturity were also significantly increased,so the grain yield,grain nitrogen accumulation and grain quality were significantly improved.Moreover,the regulation effect on quality under AFI was greater than that under EFI.In conclusion, AFITD could not only improve the shoot nitrogen accumulation at anthesis and after anthesis, but also significantly increased the amount of pre-anthesis nitrogen translocation to grain, and the shoot nitrogen accumulation and its distribution rate in grain at maturity, thus finally synergistically improved grain yield and quality of furrow-seeding wheat. Therefore, alternative furrow irrigation combined with topdressing nitrogen at jointing stage could be recommended as an alternative mode in dryland.

In order to investigate the effects of nitrogen application rates on the accumulation and distribution characteristics of dry matter and nitrogen,yield and components of maize in the key growth period under different ecological conditions in Inner Mongolia,experiments were carried out in three ecological zones,Tumed Right Banner of Baotou City,Harqin Banner of Songshan District of Chifeng City and Wuyuan County of Bayannur City of Inner Mongolia in 2021.Using maize varieties Xianyu 335,Zhengdan 958 and Jingke 968 as experimental materials,the effects of nitrogen application rate on dry matter and nitrogen accumulation,distribution,transport and yield formation in different organs of maize were studied.The results showed that the interaction between ecological zone and nitrogen fertilizer had a extremely significant effects on dry matter accumulation and distribution,nitrogen accumulation and distribution,yield and its component factors.The proportion of dry matter in various organs of maize varieties in different ecological regions was different,in order of grain>stalk>cob+bract>leaf blade.The difference was mainly manifested in the silking maturity stage. At N2 level,Xianyu 335 had higher dry matter accumulation before flowering and Zhengdan 958 had higher dry matter accumulation after flowering.At the N1 level,the stalk transfer volume,stalk transfer rate and stalk contribution rate of Jingke 968 showed good performance.The nitrogen accumulation of maize varieties with different nitrogen efficiency showed an increasing trend with the advance of growth period.The nitrogen distribution in all organs at maturity stage was grain>leaf blade > cob + bract > stalk.The maize yield in different ecological regions was Harqin Banner>Wuyuan County>Tumed Right Banner.Under the N0 level of Tumed Right Banner,the yield was Xianyu 335>Jingke 968>Zhengdan 958;at the N1 and N2 levels,the yield performance was Zhengdan 958>Jingke 968> Xianyu 335.At the different nitrogen levels in Wuyuan County and Harqin Banner,the yields were Zhengdan 958>Jingke 968>Xianyu 335,and the differences between varieties were significant(P<0.05).In conclusion,the response of nitrogen fertilizer level to Xianyu 335 dry matter accumulation was better in Wuyuan County and Tumed Right Banner.And the response of Jingke 968 and Zhengdan 958 to dry matter accumulation was better in Harqin Banner.Compared with Jingke 968,Xianyu 335 and Zhengdan 958 had better utilization of nitrogen fertilizer at the later growth stage.

To determine the effects of different nitrogen levels on soil nutrient characteristics and on the differences in nitrogen,phosphorus,and potassium uptake and utilization of summer maize,a field experiment had been conducted at four nitrogen rates(N0:No nitrogen application;N1:90 kg/ha;N2:195 kg/ha;N3:300 kg/ha)following nitrogen application of 240 kg/ha on preceding winter wheat.The experimental material Cangyu 76 was used to research the effects of nitrogen application rate on different characters of growth indicators and their correlation.The results showed that the dry matter weight of stem,leaf and corn crobs increased with the increase of nitrogen application ranged in 0-195 kg/ha.Soil nitrate N content in 0-20 cm and 20-40 cm soil layers increased significantly with increasing N application rate;but the content of available P and available K in the same soil layer had no significant change.There were significant differences in nitrogen concentration and nitrogen accumulation in stems,leaves,corn cobs and grains under different nitrogen application rates,in which nitrogen accumulation in seeds accounted for 59.4%-63.5% of total nitrogen accumulation in above-ground parts of plants.The P and K contents in stems,leaves,corn crobs and grains had little change under nitrogen application rate,but was positively regulated by dry matter weight.When N input exceeded 195 kg/ha,nitrogen agronomic efficiency was decreased significantly.When the nitrogen rate was higher than 189 kg/ha,grain yield would be not increased,which was evaluated by Linear plus platform model that simulate the relationship between yield and nitrogen application rate.Therefore,combined with experimental and model simulation results,the optimal nitrogen input was controlled within the range of 189-195 kg/ha,which could realize both economic benefits and agroecological benefits.

To investigate the effects of different application rates of nitrogen fertilizer on soil characteristics of spring wheat and pea intercropping,spring wheat monoculture and pea monoculture.Three planting methods including intercropping of wheat and pea(SI),sole cropping of spring wheat(SS)and sole cropping of pea(PS)were set,and four nitrogen application levels 0(N0),90(N1),180(N2),270 kg/ha(N3)were set.At 85 days after sowing,the activities of five soil enzymes,including sucrase, β-glucosidase,urease,glutaminase and phosphatase,and the contents of five soil nutrients,including total nitrogen,alkali-hydrolyzed nitrogen,total phosphorus,available phosphorus and organic carbon were measured.The results showed soil sucrase activity was increased(65.51%,57.88%)by N application(N2,N3)in PS soil,and N2 level reached the maximum value.Under four nitrogen levels,the sucrase activity of SI planting pattern was significantly increased by 31.25%-94.07% compared with PS.N3 treatment significantly increased SS β-glucosidase activity(17.81%);soil urease activities in SS and SI were increased by N application,and reached the highest at N2 level,SI>SS>PS under the same fertilization;N2 significantly increased the glutaminase activities in SS,SI and PS soils(26.95%,67.05%,55.03%,respectively).Soil phosphatase of SS,SI and PS all reached the highest level in N2,and SI was significantly higher than SS and PS(increased by 128.35%,337.21%,respectively).Nitrogen application could increase soil alkali-hydrolyzed nitrogen,total phosphorus and available phosphorus contents,among which alkali-hydrolyzed nitrogen and available phosphorus reached the highest at N2 level;soil sucrase activity was very significantly correlated with the urease, phosphatase, and significantly correlated with the available phosphorus content. Soil urease activity was very significantly correlated with phosphatase activity and alkaline hydrolyzable nitrogen content, and was significantly correlated with total nitrogen and available phosphorus content. Soil phosphatase activity was very significantly correlated with total nitrogen, available phosphorus content, and significantly correlated with alkaline hydrolyzable nitrogen. The total nitrogen content of soil was very significantly correlated with alkaline hydrolyzable nitrogen.There was a significant interaction between nitrogen treatment and planting mode pattern on soil urease,glutaminase,phosphatase activities,soil total phosphorus,available phosphorus contents.In conclusion,180 kg/ha was the best nitrogen application rate,and intercropping was better than monoculture under the same nitrogen application rate.

Soil phosphorus(P)cycle are varied in different land use soils.The transformation of soil organic P by hydrolyzing by enzymes is an important process in soil P cycling.The exogenous carbon(C)and nitrogen(N)application can influence on the biological process of soil P,which could play a key role in improving soil P bioavailability.In order to study the effects of exogenous C and N on soil organic P and extracellular enzyme activities in different land use soils,four soils from greenhouse vegetable field,grain field,grassland and forest were collected to conduct the incubation experiment.For each soil,four treatments were designed,including control(CK),glucose(G,500 mg/kg soil),potassium nitrate(N,300 mg/kg soil),glucose and potassium nitrate(GN,500 mg/kg glucose soil and 300 mg/kg potassium nitrate soil).The results showed that the soil organic P in greenhouse vegetable field and forest was increased after adding carbon source,increased by 89.7%,40.6%,respectively,compared to control treatment;with the addition of nitrogen sources,the available P in greenhouse vegetable soil increased by 14.2%,while that in forest soil decreased by 14.0%;compared to control treatment,the activity of alkaline phosphatase in grassland and forest soil decreased by 35.9%,25.5% with the input of carbon source,while that in greenhourse vegetable field and grain field soil had no significant effect;compared to control treatment, the β-glucosidase activity of four soils were increased by adding C and N, and the difference was significant in greenhouse vegetable field and grassland soil; based on the addition of carbon source,N addition reduced the cumulative release of CO₂ in grassland and forest soils by 19.7%,16.5%,respectively,but had no significant effect on that of greenhouse vegetable field and grain field soil.Therefore,in greenhouse vegetable field and grain field soil,the soil extracellular enzyme activity increased significantly after the application of exogenous carbon and nitrogen,and the mineralization of organic phosphorus into inorganic phosphorus was more.The content of soil organic carbon was the main factor affecting the mineralization of organic phosphorus in soil;in grassland and forest soil,the application of exogenous carbon and nitrogen reduced the activity of alkaline phosphatase and slowed down the mineralization process of organic phosphorus,so the activity of phosphatase was the main factor affecting the mineralization of organic phosphorus in the soil.

In order to explore the effects of different planting densities and potassium(K)application rates on dry matter accumulation and translocation,yield and K use efficiency of maize in the typical black soil region of Northeast China,the two-year continuous located experiment was studied the effects of different planting densities(D1:5.5×10⁴ plants/ha,D2:7.0×10⁴ plants/ha and D3:8.5×10⁴ plants/ha)and K application rates(K0,K40,K80,K120 and K160)on dry matter accumulation and translocation,K use efficiency and yield of maize in Gongzhuling City of Jilin Province.The results showed that there was a significant or extremely significant interaction between planting density and K application rate on dry matter accumulation of maize.The maximum and average accumulation rates of dry matter in D2K120 treatment were at the highest values,and the translocation amount and contribution rate of dry matter remained at higher levels.K recovery efficiency(REK),agronomic efficiency(AEK)and partial factor productivity(PFPK)at the same planting densities decreased with increasing K application rate,and the values reached the highest in D2 under the same amount of K application.Under the same K application rate,the maize yield in D2 was at the highest value.The average yields in two years under D2 were increased by 6.9%,3.0% than D1 and D3,respectively.At the same density,maize yield was significantly improved due to K fertilizer application.Among them,the yield increasing was no longer significant exceeding 80 kg/ha of K application rates under D1,and it was no longer significant exceeding 120 kg/ha of K application rates under D2 and D3.According to fitting a linear-plateau model,the appropriate ranges of K application rates were 72-80 kg/ha,104-115 kg/ha,105-116 kg/ha under D1,D2 and D3,respectively.Under the condition that K application rate in D2 was increased by 44.5% than that in D1 and was equal to that in D3,the maize yield in D2 was increased by 9.8%,3.2%,and REK was increased by 4.1,4.9 percentage points than D1 and D3,respectively.In conclusion,the planting density of 70 000 plants/ha and K application rate of 104-115 kg/ha are appropriate in the typical black soil region of Northeast China.

Partial substitution of chemical fertilizer with organic fertilizer is being increasingly recognized as a promising approach for achieving sustainable agriculture.This paper explores the proportion of organic fertilizer substitution nitrogen fertilizer,physiological basis for stable yield after substitution nitrogen fertilizer,and the effect of spraying liquid nitrogen after substitution nitrogen fertilizer in North China,in order to provide a basis for the technology of reducing nitrogen fertilizer and increasing yield and efficiency of winter wheat in this region.Field experiments of the following eight treatments were conducted in Ningjin,Hebei from 2020 to 2022:T1,non-nitrogen,application of chemical P and K fertilizer alone;T2,application of chemical N,P and K fertilizer alone;and T3- T7,substitution of 20%,40%,60%,80%and 100% the chemical N rate of T2 with organic fertilizer,respectively;T8,substitution of 100% chemical N rate of T2 with organic fertilizer,and spraying liquid nitrogen fertilizer at the erecting stage.The results showed that the organic fertilizer substitution rate of 29.5%-66.7% and the 100% substitution rate+liquid nitrogen treatment had higher wheat yield,and their yield was comparable to the CK.Under this fertilization condition,the leaf area index and leaf SPAD value were also higher at most stages,which was the physiological basis for stable yield after replacing chemical fertilizer with organic fertilizer.When the organic fertilizer substitution rate was greater than 40%,the wheat grain quality was higher,especially when the organic fertilizer substitution rate was 40%,the stability time,tensile area,and maximum tensile resistance were increased by 17.8%,23.5%,and 9.1%,respectively,compared to the CK.The nitrogen efficiency indicators of the CK,40% substitution rate,and 100% substitution rate+liquid nitrogen fertilizer treatments mostly performed better,with higher nitrogen uptake of grain,nitrogen fertilizer efficiency and nitrogen uptake efficiency.Substitution of chemical fertilizer with organic fertilizer significantly increased the nitrate nitrogen content in soil 0-80 cm from the erecting to the filling stage and 0-60 cm at the mature stage,resulting in a phenomenon of surface accumulation of soil nitrate nitrogen.The higher the replacement rate of organic fertilizer,the higher the nitrate nitrogen content in this layer of soil.Replacing nitrogen fertilizer with organic fertilizer could significantly reduce the nitrate nitrogen content of 80-100 cm soil in the mature stage,thereby reducing the risk of nitrogen leaching in the rainy season.Based on the above conclusions,the treatment of 40% substitution rate and 100% substitution rate+liquid nitrogen fertilizer had excellent wheat yield,quality,and nitrogen efficiency,with significant benefits.

It aimed to research the variation of mineral elements in the maize grain under the nitrogen(N)and zinc(Zn)fertilization,in order to provide scientific references for N and Zn application in the maize production.In the field plot experiment,two varieties including ZD958 and GSY66 were fertilized with three N rates(90,180 and 225 kg/ha)and four Zn treatments(no Zn,spraying Zn of 1∶1 at seedling stage and jointing stage,spraying Zn of 1∶1 at jointing stage and flare opening stage and spraying Zn at flare opening stage),to analyze the effects of N and Zn fertilization on the maize grain yield and mineral elements concentration and accumulation.The results showed that grain yield was significantly decreased,while Ca,Cu,Fe and Zn concentration as well as Cu and Fe accumulation were significantly increased when the N rate was more than 180 kg/ha.N and P,K,Mg concentration achieved the highest and lowerest values respectively under the 180 kg/ha N treatment.Spraying Zn of 1∶1 at jointing stage and flare opening stage and at flare opening stage only could significantly improve the yield,N and Zn concentration and N,Mg,Zn,B and Na accumulation,but decrease the P,K,Ca,B and Na concentration.Relative to GSY66,the grain yield of ZD958 was significantly increased by 19.3%,and K and Fe concentration and K,Ca,B and Na accumulation were also significantly increased.Grain yield showed extremely significantly negative correlation ship with most mineral element concentration.The positive correlationships among Ca,Mg,Cu,Mn,Fe,Zn and B were significant or extremely significant,expect for Ca and Mg,Zn.The linear regression relationships between grain Zn concentration and N,Mg concentration were significant or extremely significant.To sum up,applying 180 kg/ha N and spraying 4.5 kg/ha Zn of 1∶1 at jointing stage and flare opening stage could increase maize grain yield,N and Zn concentration and mineral elements accumulation,synchronously achieve the high yield and mineral nutrition,and are recommended to promote in maize production.

In order to effectively improve the 1000-grain weight of winter wheat,explore the effect of different drip irrigation and fertilization frequency on grain filling and mature grain shape of medium strong gluten wheat in the Huang-Huai-Hai wheat region,under the field experimental conditions,different winter wheat varieties with medium strong gluten were selected as experimental materials,a comparative experiment was carried out on different drip irrigation fertilization frequency(2,3,4 times,respectively represented by DF2,DF3,DF4)and traditional irrigation fertilization(CK)under 210 kg/ha of total nitrogen application(urea form)and 120 mm of total irrigation.The results showed that there were significant or extremely significant correlations between grain shape(except length and roundness),key grain filling parameters(V_mean,V_max,V₂,M₂)and 1000-grain weight through correlation analysis.Drip irrigation increased V_mean (average filling speed),V_max (maximum filling speed),V₂ (grain filling speed in rapid growth period),and M₂ (grain accumulation in rapid growth period).Compared with two times of topdressing with water and fertilizer(DF2),after three water and fertilizer applications(DF3),T_max,V_mean,V_max,V₂,M₂,and grain area all increased,and after four water and fertilizer applications(DF4),T_max,T₂,M₂ had improved.Compared with DF2,the length,width,thickness,roundness,and grains area increased with the frequency of fertilization(DF3 and DF4),the width and grain area of DF3 reached a significant level,and the thickness of DF4 reached a significant level,reducing the vertical and horizontal.The sieving equivalent of 2.2-2.5 mm was significantly reduced,and the sieving equivalent of >2.8 mm was increased,and the grains were more plump.Compared with border irrigation,the grains of DF3 and DF4 were also more plump.In conclusion,in wheat production,it is very important to increase the frequency of fertilization through drip irrigation to optimize the development of spike grains and improve grain weight.