秸秆还田深度对稻田土壤磷生物有效性的影响

Effects of straw returning depth on soil phosphorus bioavailability in paddy fields

研究水稻秸秆还田深度对稻田土壤磷生物有效性的影响,探索黄棕壤性水稻土最适秸秆还田深度,可为提高秸秆利用率和改善土壤理化性质提供科学依据。通过室内培养试验,设置水稻秸秆还田0 cm(S0)、10 cm(S10)、20 cm(S20)、30 cm(S30)土层,以及添加腐熟剂(F)和不添加腐熟剂两种条件。结果表明:还田至10 cm土层并添加腐熟剂的处理(S10+F)各取样期的腐解率最高,秸秆释放磷的速率也最高;秸秆还田后提高了磷生物有效性,其中主要提高各土层中稳性无机磷和活性无机磷的含量,秸秆还田12周后,10 cm土层秸秆还田提升磷生物有效性的幅度最大,S10、S10+F处理的中稳性无机磷含量比10 cm土层无秸秆对照分别提高了44.04、50.48 mg/kg,30 cm还田提升的幅度最小。因此在该地区秸秆还田10 cm深并配施腐熟剂效果最好。

This study is aimed to investigate the effect of rice straw returning depth on soil phosphorus bioavailability in paddy field,and explore the optimum straw returning depth for yellow-brown paddy soil,and provide scientific basis for improving straw utilization rate and soil physicochemical properties.Through the indoor culture experiment,the rice straw was returned to the field at 0,10,20 and 30 cm soil layer,and two conditions were set up:adding decomposing agent and not adding decomposing agent.The results showed that the decomposing rate was basically the highest in each sampling period in the treatment of returning to the field to 10 cm soil layer and adding decomposing agent,and the rate of phosphorus release from straw was also the highest.The bioavailability of phosphorus was improved after the straw was returned,and the content of stable inorganic phosphorus and active inorganic phosphorus in each soil layer was mainly improved.After 12 weeks of straw returning to the field,the 10 cm soil layer treatment showed the largest increase in phosphorus bioavailability,compared with no straw control of 10 cm soil layer,the moderately stable inorganic phosphorus content in the S10 and S10+F treatments were increased by 44.04 and 50.48 mg/kg,respectively.The 30 cm return to the field had the smallest improvement.Therefore,the best effect is to apply decomposing agent at a depth of 10 cm when straw is returned to the field.