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排水循环灌溉具有提高降水资源利用率和减少农田面源污染的潜力,为缓解我国南方地区降雨分布与水稻作物需水时间不匹配和农田磷流失污染的问题,开展了排水循环灌溉条件下稻田磷素时空分布规律研究.采用田间试验的方法,监测藕塘水和鱼塘水循环灌溉下水稻田面水和渗漏水中总磷、可溶性磷和可溶性反应磷的质量浓度,及土壤剖面总磷与Olsen-P含量的变化.结果表明,排水循环灌溉下水稻田面水和渗漏水中不同形态磷素质量浓度沿程降低,尤其渗漏水磷质量浓度的减少趋势更为显著,排水循环灌溉水源中磷质量浓度在一定范围内的变化不会增加田面水和渗漏水中的磷质量浓度.田面水和渗漏水中不同形态磷质量浓度在不同灌溉时期的变化较大,8月田面水和渗漏水的磷质量浓度明显低于其它时期.表土Olsen-P含量随距进水口的距离的增加而减少,并随排水循环灌溉水中磷质量浓度的增加而增加;土壤剖面TP含量受排水循环灌溉的影响不明显.在8月水稻需肥高峰期进行排水循环灌溉或延长灌溉水的流程,可明显改善排水循环灌溉下稻田的磷素去除效率.
Drainage irrigation has the potential to improve the utilization of precipitation resources and reduce non-point source pollution of farmland. In order to alleviate the problem that the distribution of rainfall in southern China does not match with the demand of rice crop and the phosphorus pollution in farmland, The spatial and temporal distribution of total phosphorus, soluble phosphorus and soluble phosphorus in surface water and leachate of lotus pond water and fish ponds were measured by field test method, and the total phosphorus and Olsen- P content.The results showed that the different forms of phosphorus concentration in surface water and leaking water of the paddy fields decreased along the drainage and irrigation schedule, especially the leakage phosphorus concentration decreased more obviously, The change of concentration in a certain range does not increase the phosphorus concentration in surface water and leaking water.The variation of phosphorus concentration in different forms of phosphorus in surface water and leachate has a great change in different irrigation periods. Phosphorus concentration was significantly lower than the other periods.The topsoil Olsen-P content decreased with increasing distance from the inlet, and with the drainage cycle The content of TP in the soil profile was not significantly affected by the drainage and recirculation irrigation.Drainage irrigation or prolongation of the irrigation water flow during the peak season of fertilizer demand in August could obviously improve the irrigation efficiency of the paddy field Of phosphorus removal efficiency.