节水防污型农田水利系统方案设计及应用研究

鉴于我国传统的灌排模式及粗放型水稻种植方式,未经任何处理的稻田排水携带高浓度氮磷元素直接排入下游,引起水质恶化,造成水稻灌区严重的农业面源污染。基于农业面源污染的研究现状,构建了由田间水肥综合调控-田间草沟-湿地-骨干生态沟"四道防线"组成的净化农田排水的节水防污型农田水利系统,为验证该系统的净化效果,在广西桂林市青狮潭灌区及桂林灌溉试验中心站开展对比试验研究。试验表明,氮磷排放负荷指标沿程逐级下降,通过"四道防线"后,总氮、铵态氮、总磷负荷分别削减了70.4%、83.5%、61.0%,净化效果明显。研究内容不仅丰富了农业面源污染治理的控制方法和管理措施,也对我国南方水稻灌区面源污染治理具有现实意义。

Design of Water-saving and Pollution-prevention Irrigation System

In view of the traditional irrigation and drainage model and the extensive rice cropping patterns in China,because the high-concentration nitrogen and phosphorus in the discharged water from the paddy field was not purified and directly discharged into the downstream,the quality of the water has been deteriorated,and serious agricultural non-point source pollution occurred.Based on the current situation of research on the agricultural non-point source pollution abatement,A“Four Defense Lines”irrigation and wa-ter conservancy system with water-saving irrigation and fertilizer regulation,field grass ditches,pond wetlands and ecological trunk ditches to purify the water discharged form paddy field is built in the paper.To verify the purification effect of the system,a compar-ative test was systemically carried out in Qingshitan reservoir irrigation area in Guilin and Guilin Center Station of Irrigation Experi-ment.The results of the experiments show that N and P discharge load decrease along the way;By Using “Four Defense Lines”,the effects of reducing of total nitrogen,ammonia nitrogen,total phosphorus by comprehensive system are 70.4%,83.5%,61.0% re-spectively.The research enriches controlling and management of the agricultural non-point source pollution abatement and has practi-cal significance to abate the agricultural non-point source pollution of rice irrigation in the southern China.