秸秆还田与有机无机肥配施在稻麦轮作体系下对籽粒产量及氮素利用的影响

Effect of straw returning and combined applications of organic fertilizer and inorganic fertilizer on grain yield and nitrogen utilization under rice-wheat rotation system

为探究太湖地区稻麦轮作区秸秆还田与化肥、牛粪堆肥配合施用下水稻和小麦产量以及氮素利用情况,通过大田试验比较不同施肥方式,即不施肥(CK)、单施化肥(CF,当地常规施用量)、70%CF+牛粪堆肥(OMCF)、CF+秸秆全量还田(CF+S)和OMCF+秸秆全量还田(OMCF+S)对稻麦产量及氮素吸收利用的影响。结果表明:稻麦产量从大到小的处理依次为OMCF+S、CF+S、OMCF、CF、CK。与CF处理相比,施用有机肥料提高了库容量和千粒质量,促进了干物质和氮素在作物生育后期的积累,并提高了干物质和氮素在籽粒中的分配比例,使生物产量更多地转化为经济产量;施用有机肥料还有利于营养器官中氮素的转运,从而提高了氮肥利用率。其中,秸秆和有机肥协同施用(OMCF+S)对作物氮肥利用的促进作用比OMCF和CF+S处理单独施用更明显;OMCF+S处理加强作物生育中后期土壤的供氮能力,改善作物生育中后期的营养条件,从而促进幼穗分化和籽粒灌浆,为产量的提高奠定基础。结论:在化肥施用量减少30%的基础上配施有机肥同时秸秆全量还田实现产量构成因素在较高的层次上协调统一,从而获得较高的产量,同时通过作物与土壤的自我调控实现氮肥利用率的提高。

In order to explore the effect of returning whole straw associated with combined cow manure and reduced chemical fertilizer application on grain yield,uptake and use of nitrogen under rice-wheat rotation system in Tai Lake region,an experiment was laid out with randomized design with four replicates of five treatments,respectively,CK（ non-fertilization）,CF（ inorganic fertilizer that N application was 240 kg·hm-2）,OMCF（ 70%CF with 3 000 kg·hm-2cow manure）,CF＋S（ CF＋returning whole straw） and OMCF＋S（ OMCF＋returning whole straw）. Each plot was 46 m2 in area and isolated by plastic waterproof membrane to prevent the water and nutrients exchange between plots. The soil in ploughed layer before the experiment contained 21. 5 g·kg-1soil organic matter,2. 30g·kg-1total nitrogen,0. 93 g·kg-1total phosphorus,140 mg·kg-1available nitrogen,39. 0 mg·kg-1available phosphorus,74. 3mg·kg-1available potassium and pH 7. 6. The grain yield and yield component,accumulation,distribution and translocation of nitrogen and dry matter aboveground,N use efficiency and amount of soil mineral nitrogen at each treatment were measured /calculated for comparison. The results showed that change rule of grain yield in treatments as follows： OMCF＋S,CF＋S,OMCF,CF,CK,application of organic fertilizer promoted sink capacity and thousand seed weight. Application of returning whole straw associated with combined cow manure and reduced chemical fertilizer promoted dry matter accumulation and nitrogen uptake,and also increased the distribution of dry matter and N to the grain at mature,which was beneficial for the transformation from biological yield to economic yield. It also improved assimilation of dry matter at filling stage and translocation of N in vagetative,and thereby promoted nitrogen use efficiency. The increment of OMCF＋S treatment＇s nitrogen use efficiency was more obvious than OMCF or CF＋S separately as a result of cooperative action of returning whole straw and cow manure. The increased content of soil mineral nitrogen at mid-late growth stage by application of returning whole straw or cow manure,especially OMCF＋S,improved nutritional conditions at mid-lategrowth stage of crop,improved young spike differentiation and grain-filling,and laid a foundation for increment of grain yield. Conclusions： Cooperative action of straw returning and combined application of cow manure and chemical fertilizer improved the coordination of yield component at a higher level,and higher yield was obtained,meanwhile,it improved N use efficiency by the realization of self-regulation of crop-soil.