紫云英和秸秆替代部分化肥对双季稻产量、养分含量及土壤综合肥力的影响

化肥对于农业生产的意义重大，但过量施用化肥将增加面源污染风险。为了优化施肥结构，减少养分流失，利用紫云英和秸秆替代部分化肥，可以在保证双季稻稳产的同时提高稻田土壤肥力。本文基于连续四年田间定位实验，探讨了紫云英和秸秆替代部分化肥对双季稻产量、土壤综合肥力和植株养分含量的影响。试验设置六个等养分投入的处理：（1）冬闲+氮、磷、钾（CF）；（2）冬闲+秸秆低量还田+氮、磷、钾（RSL）；（3）冬闲+秸秆高量还田+氮、磷、钾（RSH）；（4）紫云英+氮、磷、钾（MV）；（5）紫云英+秸秆低量还田+氮、磷、钾（MV＋RSL）；（6）紫云英+秸秆高量还田+氮、磷、钾（MV＋RSH）。结果表明：早稻季，将有机物料替代比例控制在20%以内，水稻产量保持稳定；当替代比例达到39%及以上时，水稻产量显著降低。晚稻季，与CF处理相比，其余各处理提高了土壤有机质和全氮含量，其中，以RSH处理提升效果最为明显，分别提高了11.15%和7.64%。与RSH处理相比，MV+RSH处理土壤综合肥力指数提高了8.5%。与CF处理相比，MV和RSH处理显著提高了稻谷磷、钾含量。等养分投入条件下，利用2500kg/hm2秸秆替代20%化肥在保证水稻稳产的同时提高了土壤肥力。紫云英与秸秆联合利用能显著改善土壤肥力状况，但该模式下替代化肥的比例过高在短期内可能有减产的风险。

Effects of Chinese Milk Vetch and Straw Substituting Fertilizers on Double Rice Yield and Soil Integrated Fertility

Chemical fertilizers (CF) exhibits significant importance for agricultural production. However, excessive application of CF also raises the risk of environmental pollution. In order to optimize the fertilizer application structure and reduce nutrient loss, the rational use of Chinese milk vetch and straw to substitute CF improve soil fertility while ensuring stable crop yield. This study was based on four consecutive years of field experiment, which equipped with 1) Winter fallow + N, P, K (CF); 2) Winter fallow + low amount of rice straw returning + N, P, K (RSL),; 3) Winter fallow + high amount of rice straw returning+ N, P, K (RSH); 4) Chinese milk vetch + N, P, K (MV); 5) Chinese milk vetch + low amount of rice straw returning + N, P, K (MV+RSL); 6) Chinese milk vetch + high amount of rice straw returning + N, P, K (MV+RSH), a total of 6 treatments. We comparatively analyzed the rice yield, soil integrated fertility and plant nutrients among different treatments. In early rice season, the rice yield remained stable when the organic substitution ratio was kept within 20%; however, when the substitution ratio reached 39%, the rice yield significantly decreased. In late rice season, compared with the CF treatment, organic matter returned significantly increased soil organic matter and total nitrogen content, among which, the RSH treatment had the most significant enhancement effect. Different proportions of Chinese milk vetch and straw replacing CF improved soil integrated fertility index (IFI). Compared with the RSH treatment, the IFI of MV+RSH-treated improved 8.5%. The MV and RSH treatments significantly increased rice phosphorus and potassium content when compared with the CF treatment. Under the equal nutrient inputs, using 2500 kg/hm2 rice straw to replace 20% CF could ensure stable rice yield and increased soil fertility at the same time. The co-utilization of Chinese milk vetch and rice straw significantly increased soil fertility, however, the over-representation of organic substitution may result in diminished output in a short time.