摘要： 为提高设施农田氮素利用，减少土壤氮素积累，选用填闲糯玉米和饲用甜高粱为供试作物，设计6个不同用量水平生物炭，即C1（0）、C2（0.5%）、C3（1%）、C4（2%）、C5（4%）、C6（8%），研究生物炭施用对夏填闲作物氮素吸收及土壤碳氮变化的影响。结果表明：2种填闲作物随着生物炭施用量的增加，吸氮量先增大后减小，其中填闲糯玉米C3处理地上部吸氮量最大（142.69 kg/hm²），而填闲饲用甜高粱是C4处理最优（132.43 kg/hm²）；填闲糯玉米不同处理土壤全氮降低幅度为2.5%~11.0%，其中C3处理降低最多（15.4%），各个处理之间差异不显著（P>0.05），填闲饲用甜高粱除C6处理外，其他处理降低幅度为1.4%~15.5%，C3处理降低最多；种植饲用甜高粱后，不同处理不同土层土壤硝态氮含量与种植前相比均有所降低；不同用量生物炭与填闲作物结合种植均能提高设施土壤C/N值，施用生物炭后有利于增加有机碳含量，种植填闲作物能降低后茬生长初期土壤脲酶活性，降低后茬作物生长时期氮素的供给能力；随着生物炭施用量的增加，各处理土壤脲酶活性先增加后减少，定植15 d后NC3（前茬糯玉米+C3）处理脲酶活性最高，为3.33 mg/（g·d），填闲饲用甜高粱种植后，定植45 d后，TC3（前茬甜高粱+C3）处理最高，TC2（前茬甜高粱+C2）处理次之。生物炭施用与填闲作物种植结合能增加后茬初期土壤微生物量碳含量，有利于土壤肥力提高。在本试验条件下得出，生物炭施用量在1%~2%种植填闲糯玉米促进氮素吸收效果较好，生物炭施用量在0.5%~2%种植填闲饲用甜高粱促进氮素吸收效果较好，有利于减少土壤氮素积累，种植填闲饲用甜高粱比种植填闲糯玉米对降低土壤氮素移动的效果更好。

关键词: 填闲作物, 设施土壤, 土壤碳氮, 生物炭

Abstract: In order to improve nitrogen utilization in facility farmland and reduce soil nitrogen accumulation,waxy corn and feeding sweet sorghum was selected as the catch crops,and six different levels of biochar were designed,namely C1(0),C2(0.5%),C3(1%),C4(2%),C5(4%),C6(8%),to study the effects of biochar application on nitrogen uptake by summer crop and soil carbon and nitrogen changes.The results showed that with the increase of biochar application rate,the nitrogen uptake of the two crops first increased and then decreased.Among them,the nitrogen uptake of the aboveground part of the waxy corn C3 treatment was the largest(142.69 kg/ha),feeding sweet sorghum was the best C4 treatment(132.43 kg/ha);the soil total nitrogen decreased by 2.5%-11.0% among different treatments,and the C3 treatment decreased by the most(15.4%),except for C6 treatment, the decrease range of other treatments for feeding sweet sorghum was 1.4% to 15.5%, and the decrease was the most in C3 treatment. After planting feeding sweet sorghum,different treatments and different soil layers had reduced nitrate nitrogen content compared with before planting;The C/N value of the facility soil could be increased by combining different amounts of biochar with catch crops;the application of biochar was beneficial to increase the organic carbon content,the planting of catch crops could reduce the soil urease activity in the early growth period of the subsequent crops,and reduce the nitrogen supply capacity of the subsequent crops during the growth period.With the increase of the application amount of biochar,the soil urease activity increased firstly and then decreased in each treatment.The highest urease activity was 3.33 mg/(g·d) in NC3(preceding waxy corn+C3) treatment after planting for 15 days.After planting for 45 days,the highest urease activity was in TC3(preceding sweet sorghum+C3) treatment,followed by TC2(preceding sweet sorghum+C2) treatment.The combination of biochar application and crop cultivation could increase the soil microbial biomass carbon content at the beginning of the subsequent crop,which was beneficial to the improvement of soil fertility.Under the conditions of this experiment,it was concluded that planting waxy corn with 1%-2% biochar application rate had a better effect on nitrogen absorption,and planting filling feeding sweet sorghum with 0.5%-2% biochar application rate had a better effect on nitrogen absorption,which was beneficial to reduce soil nitrogen accumulation.Planting feeding sweet sorghum has a better effect on reducing soil nitrogen movement than planting waxy corn.

Key words: Catch crops, Facility soil, Soil carbon and nitrogen, Biochar

中图分类号: 

• S158.3