field drainage meaning in English

农田排水

Tp is rise with high frequency of rainfall and field drainage from june to september
6 9月频繁的降雨和水稻田排水，造成湿地水中tp浓度上升。
Tp ( total phosphorus ) has accumulated in the whole layers of sediments from surface to 100cm . 2 . the variation of non - point source pollutants after input to wetalnds with rain runoff and fields drainage the concentrations of cod , tn and nh / - n are decreased after input to wetalnds with rain runoff and fields drainage
降雨径流和农田排水中非点源污染物进入沟渠湿地后的变化特征降雨径流和农田排水中的cod 、 tn 、 nh _ 4 ~ + - n进入湿地后，浓度均显著降低，证明湿地对非点源污染物有很好的截留和净化效果。
The ditches are the first pool of diffuse nutrients from rain runoff and field drainage , and are shaped to a net work in the area of the lower reaches of the changjiang river where the cultivation manner of fields are rotation of rice and wheat . now we have learnt little about the mechanisms of pollutants trasport and transformation in ditch wetlands
长江下游水稻-小麦轮种区沟渠湿地呈网络状密集分布，是降雨径流和农田排水的首要汇聚地，我们对污染物在沟渠湿地中迁移转化的机理还知之甚少，本文分析了： 1