不同水稻灌溉模式和氮肥减量对还田麦秸腐解特性及土壤养分的影响

为了探讨不同水稻灌溉模式和氮肥减量对还田小麦秸秆腐解特性及土壤养分的影响，通过田间试验，设置了水稻灌溉模式（常规灌溉，W1；干湿交替灌溉，W2）和施氮水平（不施氮，N0；常量施氮，N1；减量20%施氮，N2）处理，采用尼龙网袋法研究了不同处理下小麦秸秆腐解动态、养分释放规律及土壤养分含量。结果表明，干湿交替灌溉和氮肥施用均可促进还田小麦秸秆的腐解，减量20%施氮处理小麦秸秆累积腐解率低于常量施氮处理。相同施氮水平下，干湿交替灌溉模式小麦秸秆碳与氮磷钾累积释放率高于常规灌溉模式；与常量施氮相比，减量20%施氮处理小麦秸秆碳与氮磷钾累积释放率降低。干湿交替灌溉和施氮使土壤有机质、全氮、碱解氮和有效磷含量提高，而减量20%施氮对土壤养分含量的影响较小。综上可见，干湿交替灌溉和氮肥施用促进了还田小麦秸秆腐解和养分释放，有利于土壤养分提升；而减量20%施氮对小麦秸秆腐解与养分释放以及土壤养分无明显影响。

Effects of Different Rice Irrigation Patterns and Nitrogen Fertilizer Reduction on Decomposition Characteristics of Wheat Straw and Soil Nutrients

In order to explore the effects of different rice irrigation patterns and nitrogen reduction on the decomposition characteristics of wheat straw returned to field and soil nutrients, an experiment using nylon net bag was conducted with the treatments as follows:1) rice irrigation patterns (conventional irrigation, W1; alternate wetting and moderate soil drying irrigation, W2); 2) nitrogen application levels (no nitrogen application, N0; conventional nitrogen application, N1; 20% reduction of conventional nitrogen application, N2). The decomposition and nutrient release of wheat straw and soil nutrient contents under different treatments were studied. The results show that both W2 and nitrogen application promote the decomposition of wheat straw returned to the field. N2 decreases the cumulative decomposition rate of wheat straw compared with N1. Under the same nitrogen application level, W2 increases the cumulative release rates of carbon, nitrogen, phosphorus and potassium of wheat straw compared with W1. N2 decreases the cumulative release rate of carbon, nitrogen, phosphorus and potassium of wheat straw compared with N1. W2 and nitrogen application increase the contents of soil organic matter, total nitrogen, available nitrogen and available phosphorus, while N2 has little effect on the contents of soil nutrients compared with N1. In conclusion, W2 and nitrogen application promote the decomposition and nutrient release of wheat straw returned to field, which is conducive to the improvement of soil nutrients, while N2 has no significant effect on the decomposition and nutrient release of wheat straw and soil nutrients.