水稻田土-水系统中磷素行为及其环境影响研究

土壤测试表明供试土壤已富P.大田试验结果表明,P肥投入提高了土壤树脂P和田面水总P水平,且两者随着时间的推移而下降.但施P后的20d内,有机无机配施P肥对土壤有效P的贡献大于单施化肥P.在施P第7d时,有机无机配施P的田面水总P水平是单施化肥P的3.4倍,是施P量2倍的处理Ⅲ的2.8倍.与有机肥配施的处理,其田表水P素流失潜能较单施化肥大.经33d后,P肥结构对田面水P素的影响不明显.两次水稻季节性排水而导致的P素净流失负荷和P素表观流失率变幅分别为-0.038～0.076kg·hm^-2和0.034～0.100%.从减少水稻田排水P素流失角度考虑,可以认为,施P或土层被搅动后1周内是控制P素流失的主要环节.

Phosphorus behavior in soil-water system of paddy field and its environmental impact

A field experiment with rice showed that P fertilizer application increased the concentrations of resin P in soil and total P in soil surface water,and both of them declined subsequently over time.Compared with applying mineral P fertilizer only,the integrated application of mineral-P and manure resulted in a higher resin P level within 20 days after P application.The total P concentration in soil surface water in the treatment of integrated application of mineral-P and manure was 3.4 times higher than that in the treatment of mineral-P fertilizer application only after 7 days of P application,and also,was 2.8 times higher than that in the treatment where P application rate was doubled.The potential of Ploss from surface water in the treatment of integrated application with manure was more than that in the treatment of applying-P fertilizer only.The effect of applied P sorts on P concentration in soil surface water could be ignored after 33 days of P application.Two drainages were conducted for rice growth,which caused the net P loss loading and its apparent P loss ratio in range of -0.038～0.076kg·m^-2and 0.034～0.100%,respectively.To minimize P loss from rice production area,field drainage should be avoided in the initial week of P-fertilizer application or field harrowing.