模拟降雨条件下豫西南山区农地径流污染物变化规律

坡耕地和梯田是丹江口水库水源区常见的农地类型,为了减少养分和水土流失、改进农作措施,采用人工模拟降雨方法,研究了不同雨强下这两种用地径流中养分变化规律。结果表明:(1)两种土壤径流中TN,TP,COD随降雨时间均呈波状变化,不同雨强下梯田径流中TN的含量为:3.36mg/L(0.5mm/min时),5.18mg/L(2.5mm/min时),4.27mg/L(3.0mm/min时),坡耕地中相应为2.66mg/L,4.56mg/L,4.18mg/L;不同雨强下梯田径流中TP的含量为:0.81mg/L(0.5mm/min时),0.92mg/L(2.0mm/min时),1.56mg/L(2.5mm/min时),2.53mg/L(3.0mm/min时),坡耕地中的值依次为0.59mg/L,1.03mg/L,0.62mg/L,2.04mg/L。说明梯田中TN,TP的含量要高于坡耕地。(2)不同雨强下梯田径流中COD含量为:303.56mg/L(1.0mm/min时),685.16mg/L(2.0mm/min时),617.66mg/L(3.0mm/min时),坡耕地中则为419.63mg/L,644.62mg/L,721.17mg/L,研究表明坡耕地更易发生有机质的流失。因此,对坡耕地进行梯田化治理可减少养分和水土流失、提高作物产量。

Under Artificial Rainfall the Changing Law of Pollutants in Runoff in Farmland in Southwest Mountains of Henan Province

Slope cropland and terrace are common land use types in Danjiangkou reservoir catchment areas and indoor artificial rainfall simulation methods are employed to study nutrients' changing law of the two soils under different rainfall intensities,so as to prevent nutrients,soil and water erosion,improving farming practices.The results are as follows:(1) the nutrients of TN,TP and COD all have wavily changed in the two kind soils runoff with rainfall time,the TN content are respectively 3.36 mg/L (0.5 mm/min),5.18 mg/L (2.5 mm/min),4.27 mg/L (3.0 mm/min) in terrace in different rainfall intensity and the relevant values in hilly land are 2.66 mg/L,4.56 mg/L,4.18 mg/L;the TP content are respectively 0.81 mg/L (0.5 mm/min),0.92 mg/L (2) / 0 mm/min),1.56 mg/L (2.5 mm/min),2.53 mg/L (3.0 mm/min) in terrace in different rainfall intensity and the relevant values in hilly land are 0.59 mg/L,1.03 mg/L,0.62 mg/L,2.04 mg/L,which shows TN and TP content in terrace are higher than the one in hilly land.(2) the COD content are respectively 303.56 mg/L (1.0 mm/min),685.16 mg/L (2.0 mm/min),617.66 mg/L (3.0 mm/min) in terrace in different rainfall intensity and the relevant values in hilly land are 419.63 mg/L,644.62 mg/L,721.17 mg/L,which indicates it's more likely to happen the loss of organic matter in hilly land.Therefore,terrance engineering to hilly land can reduce nutrients loss,water and soil erosion,increase crop yield.