不同还田方式下2种夏季绿肥的腐解特性

Decomposing Characteristics of Two Summer Green Manure Crops Under Different Returning Methods

【目的】明确夏季绿肥作物的腐解规律和养分释放动态特征,为绿肥资源的合理利用和农田养分管理提供科学依据。【方法】以夏季豆科绿肥品种猫豆和赤小豆为研究对象,采用网袋法模拟其在免耕覆盖还田和翻压还田方式下的腐解动态,分析其干物质的腐解特征及碳、氮、磷和钾等养分的释放情况。【结果】在免耕覆盖还田和翻压还田方式下,猫豆和赤小豆茎秆在还田后的0~20 d腐解速率较快,之后腐解缓慢;至还田100 d时,在免耕覆盖还田方式下猫豆和赤小豆的干物质累积腐解率分别达40.11%和37.25%,在翻压还田方式下猫豆和赤小豆的干物质累积腐解率分别达70.71%和66.87%。至还田100 d时,在免耕覆盖还田方式下猫豆的碳、氮、磷和钾养分累积释放率分别为20.44%、15.64%、45.28%和83.49%,赤小豆的碳、氮、磷和钾养分累积释放率分别为17.66%、13.33%、40.33%和79.49%,而在翻压还田方式下猫豆的碳、氮、磷和钾养分累积释放率分别为65.24%、63.78%、84.36%和92.48%,赤小豆的碳、氮、磷和钾养分累积释放率分别为60.06%、58.88%、79.56%和88.20%。【结论】绿肥作物猫豆和赤小豆干物质及碳、氮、磷和钾等养分的累积释放率和释放速率表现为翻压还田>免耕覆盖还田,养分的释放速率表现为钾>磷>碳>氮;猫豆的干物质腐解及养分释放速度大于赤小豆,作为夏季绿肥品种翻压还田效果优于赤小豆。

【Objective】To provide scientific basis for rational utilization of green manure and nutrient management of farmland,the characteristics of decomposition rules and nutrients release of green manure were studied.【Method】Net bag method was used to simulate the decomposition dynamics of summer leguminous green manure of Mucuna pruriens and Vigna umbellata under straw mulching treatment and soil coverage treatment,and the decomposition characteristics of dry matter and the release of carbon,nitrogen,phosphorus and potassium were analyzed.【Result】The results indicated that the green manure decomposition speed was fast in the first 20 days,and slowed down later in both treatments.When returning to the field for 100 days,the accumulated decomposition rates of dry matter of M.pruriens and V.umbellata under straw mulching treatment reached 40.11%and 37.25%respectively,and 70.71%and 66.87%under soil coverage treatment.After returning to the field for 100 days,the accumulated decomposition rates of C,N,P and K of M.pruriens under straw mulching treatment were 20.44%,15.64%,45.28%and 83.49%respectively,and 65.24%,63.78%,84.36%and 92.48%under soil coverage treatment.The accumulated decomposition rates of C,N,P and K of V.umbellata under straw mulching treatment were 17.66%,13.33%,40.33%and 79.49%,respectively,and 60.06%,58.88%,79.56%and 88.20%under soil coverage treatment.【Conclusion】The accumulated decomposition rates of dry matter and nutrients such as C,N,P and K in green manure under soil coverage treatment were higher than that of straw mulching treatment,and the decomposition speed was also faster under soil coverage treatment.And the sequence nutrient release rates was K>P>C>N.The decomposition and nutrient release rate of M.pruriens stalk was higher than that of V.umbellata.As a summer green manure,the effect of M.pruriens returning to the field is better than that of V.umbellata.