水田冬种多花黑麦草对土壤氮磷环境释放的影响

研究以“黑麦草-水稻”草田轮作系统为基础,水田冬种多花黑麦草为研究对象,利用实验生态学的方法,通过对土壤地下渗漏水中N、P含量变化的分析,研究稻田冬种黑麦草的N、P动态,把握在种植过程中N、P向环境原位释放的数量、规律和影响因素,有利于更加客观地评价“黑麦草-水稻”草田轮作系统的环境效应。结果表明,在不施肥的冬闲田,仍可发生N素和P素的损失,一个生长周期中随土壤下渗水的损失量平均为NO₃^--N 115.98 kg/hm²,NH₄⁺-N 0.828 0 kg/hm²,P 0.028 5 kg/hm²。而冬种黑麦草降低了这种损失,其中施复合肥375 kg/hm²处理与冬闲处理相比,NO₃^--N、NH₄⁺-N和P的淋失量分别降低了49.43%,48.59%,24.11%。施肥量750 kg/hm²处理的NO₃^--N和NH₄⁺-N淋失量比冬闲处理分别降低了38.20%和15.57%,但P的淋失量比冬闲处理略高。

Effect of winter cropping Italian ryegrass on N and P leakage from soils

Based on the construction of an Italian ryegrass-rice rotation(IRR) system,the variety and dynamics of N and P loss in underground leakage water under different experimental treatments were investigated.The average loss of N and P through leakage water in the growth cycle was 115.98 kg/ha NO3——N,0.828 0 kg/ha NH4+-N and 0.028 5 kg/ha P under the idle field treatment(CK).Winter cropping of Italian ryegrass reduced the loss of N and P.Winter cropping Italian ryegrass with 375 kg/hm compound fertilizer,resulted in loss reductions of NO3——N,NH4+-N and P of 49.43%,48.59% and 24.11%,respectively,compared to the CK.Winter cropping Italian ryegrass with 750 kg/ha compound fertilizer,resulted in loss reductions of NO3——N and NH4+-N of 38.20% and 15.57%,respectively,while the loss of P was slightly greater than that under CK.