Production Benefits of Double-Cropping Rice Under Optimized Application of Nitrogen and Potassium Fertilizers Combined with Chinese Milk Vetch and Straw Co-Returning to Fields

化肥氮钾优化施用及紫云英、秸秆协同还田下的双季稻生产效益

In order to explore the technology and effects of reducing nitrogen and potassium fertilizer applications in double-cropping rice,a field plot experiment was conducted to study the effects of optimized application of nitrogen and potassium fertilizers combined with returning Chinese milk vetch and straw to fields on yield,fertilizer utilization efficiency,net photosynthetic rate(Pn),stomatal conductance(Gs),intercellular CO_(2) concentration(Ci),chlorophyll content(SPAD value)and soil physical and chemical properties in late rice harvest period.The results showed that the optimized application of nitrogen and potassium fertilizers combined with the integrated technology of Chinese milk vetch and straw co-returning to the field could enhance the photosynthetic efficiency of double-cropping rice,increase rice yield,and enhance soil biological activity,especially T4 treatment involving the returning of Chinese milk vetch and straw to the field instead of 30%nitrogen fertilizer achieved the highest rice yield,fertilizer use efficiency,net photosynthetic rate and soil biological activity.Compared with the conventional fertilization treatment T2,the total rice yield of T4 treatment increased by 4.1%,among which the early rice and late rice increased by 6.3%and 2.4%,respectively;Pn,Gs and SPAD values of flag leaves at full heading stage significantly increased,and the contents of soil active organic carbon,alkali hydrolyzed nitrogen,available phosphorus and readily available potassium significantly increased.

为探讨双季稻化肥氮钾减施技术及效果,通过田间小区试验,研究了双季稻化肥氮钾优化施用及紫云英、秸秆协同还田集成技术对双季稻产量、肥料利用效率、齐穗期剑叶叶片净光合速率(Pn)、气孔导度(Gs)、胞间CO_(2)浓度(Ci)、叶绿素含量(SPAD值)及晚稻收获期土壤理化性质的影响。结果表明:化肥氮钾优化施用及紫云英、秸秆协同还田集成技术能增强双季稻的光合效率,提高水稻产量,增强土壤生物活性,且以T4处理(紫云英和秸秆还田替代30%化肥氮)的水稻产量、肥料利用效率和净光合速率最高,土壤生物活性最强;与常规施肥处理T2相比,T4处理的2季稻谷总产量增长4.1%,其中早稻和晚稻分别增产6.3%和2.4%,齐穗期剑叶叶片Pn、Gs及SPAD值明显提高,土壤活性有机碳含量和碱解氮、有效磷、速效钾含量明显增加。