氮钾减施下紫云英翻压量对双季稻产量及氮素利用的影响

Effects of the incorporation of various amounts of Chinese milk vetch with nitrogen and potassium reduction on double cropping rice yield and nitrogen utilization

采用11年(2008—2018年)绿肥定位试验,研究氮钾减施20%下紫云英不同翻压量(15000、22500、30000、37500 kg/hm^(2))对双季稻产量、氮素利用率及土壤氮素的影响。结果表明:与不施肥相比,施肥处理的早、晚稻产量显著增加,产量可持续指数提高,且减施氮钾20%翻压紫云英处理和单施化肥处理间的11年平均产量和产量可持续指数差异均无统计学意义;通过分析2018年的数据,与当地的常规施肥处理相比,减施氮钾20%翻压紫云英30000 kg/hm^(2)能显著提高早稻生物量、氮素积累量、化肥氮素吸收利用效率(回收利用效率、农学利用效率、偏生产力)和晚稻稻草生物量、稻谷氮素积累量、总投入氮素吸收利用效率(回收利用效率、农学利用效率、生理利用率、偏生产力);适量氮钾减施翻压紫云英可提高土壤全氮和碱解氮质量分数,有效提升土壤肥力。在本研究中,氮钾减施20%时翻压紫云英30000 kg/hm^(2)较适宜。

An 11-year(from 2008 to 2018)green fertilizer experiment was conducted to study the effects of different application amounts(15000,22500,30000,37500 kg/hm^(2))of Chinese milk vetch with 20%N and K reduction on double cropping rice yield,nitrogen use efficiency and soil nitrogen.The results showed that compared with no fertilization treatment,the yields of early and late rice were significantly increased by fertilization,and the yield sustainability indexes were increased.There was no statistical significance in the 11-year average yield and yield sustainability index between the treatments of 20%N and K reduction with Chinese milk vetch and the single fertilizer application treatment.Through the analysis of the data from 2018,compared with the treatment of the conventional fertilization of local,the treatment of the N and K reduction with 30000 kg/hm^(2) Chinese milk vetch significantly increased the early rice biomass and N accumulation,fertilizer N uptake and utilization efficiency(recycling and utilization efficiency,agronomic utilization efficiency,partial productivity),and late rice straw biomass,the amounts of accumulated N of rice,total N uptake and utilization efficiency(recycling and utilization efficiency,agronomic utilization efficiency,physiological efficiency,partial productivity).Applying Chinese milk vetch with appropriate N and K reduction could increase soil total N and alkali-hydrolyzable N,and effectively improve soil fertility.In summary,the treatment of 20%N and K reduction with 30000 kg/hm^(2) Chinese milk vetch was optimal for the double cropping rice yield and nitrogen utilization.