稻秸还田下减量化施氮对小麦产量、养分吸收及土壤理化性质的影响

Effects of Reduced Nitrogen Fertilization on Wheat Yield,Nutrient Uptake and Soil Physicochemical Properties Under Rice Straw Returning

为明确稻秸还田下减量化施氮对小麦产量、养分吸收及土壤理化性质的影响,以小麦品种“宁麦16”为试验材料开展田间试验,设置不施氮对照(CK)、不同施氮量(常量施氮225 kg/hm^(2),N1;减量20%施氮180 kg/hm^(2),N2)和氮肥运筹(基肥与追肥的比例为5︰5,M1;基肥与追肥的比例为7︰3,M2)处理,测定并分析不同施氮量和氮肥运筹下小麦产量及其构成因素、养分吸收与分配、氮肥利用效率及土壤理化性质。结果表明,稻秸还田下,施氮可使小麦产量显著增加,N2处理小麦产量较N1处理仅降低了80.72 kg/hm^(2),提高基施氮肥比例可使小麦单位面积有效穗数增加。施氮显著促进了小麦籽粒、秸秆和地上部的氮素、磷素和钾素吸收,N2处理小麦氮素、磷素和钾素吸收量低于N1处理;N1和N2水平下,M2处理小麦氮素和磷素吸收量均高于M1处理,而钾素吸收量低于后者。N2处理小麦氮肥农学效率、氮肥偏生产力、氮肥表观利用率和氮素生理效率较N1处理提高,而100kg籽粒吸氮量降低。N1处理土壤碱解氮含量显著高于CK;N2处理土壤有机质、碱解氮和速效钾含量低于N1处理,而土壤有效磷含量高于后者;N1和N2水平下,M1处理土壤有机质和碱解氮含量高于M2处理,而土壤有效磷和速效钾含量表现为M2处理高于M1处理。综合来看,稻秸还田下,常规施氮量基础上减量20%,适当提高基施氮肥比例,可增加单位面积有效穗数,实现小麦高产稳产,提高氮肥利用效率。

In order to clarify the effects of reduced nitrogen fertilization on wheat yield,nutrient uptake and soil physicochemical properties under rice straw returning,a field experiment was conducted with the wheat variety“Ningmai 16”as test material.The treatments were designed as follows:1)nitrogen application:no nitrogen application control(CK),constant nitrogen application of 225 kg/hm^(2)(N1),reduced nitrogen application of 180 kg/hm^(2)(N2);2)nitrogen management:the ratio of base fertilizer to topdressing is 5︰5(M1)and 7︰3(M2).Wheat yield and its components,nutrient absorption and distribution,nitrogen use efficiency and soil physicochemical properties were measured and analyzed.The results show that wheat yield of N2 is only 80.72 kg/hm^(2)lower than that of N1.Increasing the proportion of basic nitrogen application increases the number of effective panicles per unit area.Nitrogen application significantly promotes the absorption of nitrogen,phosphorus and potassium in wheat grains,straws and shoots.The absorption of nitrogen,phosphorus and potassium of N2 are lower than those of N1.At N1 and N2 levels,nitrogen and phosphorus uptake of M2 are higher than those of M1,while potassium uptake of M2 is lower than that of M1.Nitrogen application significantly increases wheat yield.Nitrogen agronomic efficiency,nitrogen partial productivity,nitrogen apparent efficiency and nitrogen physiological efficiency of N2 are higher than those of N1,while nitrogen uptake of 100 kg grain is decreased.The content of available nitrogen of N1 is significantly higher than that of CK.The contents of organic matter,available nitrogen and available potassium of N2 are lower than those of N1,while the content of available phosphorus is higher than that of N1.At N1 and N2 levels,the contents of organic matter and available nitrogen of M1 are higher than those of M2,while the contents of available phosphorus and available potassium of M2 are higher than those of M1.In general,under the condition of returning rice straw to the field,reducing conventional nitrogen application by 20%and appropriately increasing the proportion of basic nitrogen application can increase the number of effective panicles per unit area,achieve high and stable wheat yield,and improve nitrogen use efficiency.