晋江西溪流域茶园降雨径流产污特征

Rainfall-runoff and pollution characteristics of tea garden in Xixi watershed within Jinjiang River basin

在野外模拟降雨条件下,开展了晋江西溪流域茶园和裸地的径流产沙及氮磷养分流失过程对比实验,研究结果表明,在相同降雨强度下,3种下垫面径流和产沙量顺序均为:裸地>2年茶园>4年茶园,径流量与产沙量之间呈显著正相关.对地表径流水相而言,2年茶园、4年茶园和裸地的TN流失量分别为:461.29、129.38和107.86 mg/m2;NO3-N流失量分别为:286.42、98.58和103.00 mg/m2,均占TN流失量的60%以上;NH4-N流失量分别为:48.67、16.19和4.42 mg/m2;TP流失量分别为:34.71、16.47和23.88 mg/m2。对径流泥沙相而言,2年茶园、4年茶园和裸地的TN流失量分别为:379.28、44.81和747.16 mg/m2,占流失总量的比重在25.72%～87.93%之间;TP流失量分别为:27.94、4.17和58.85 mg/m2,占流失总量的比重在53.42%～68.36%之间。茶园的N、P主要随径流流失,而裸地以泥沙迁移为主。这说明茶叶种植具有一定的水土保持效应,且种植年限较长的茶园可显著减少随径流泥沙进入水体中的N、P元素。

Field experiments on hillslope runoff,sediment and nitrogen,phosphorus losses in tea garden and bare land were carried out under simulated rainfall in the Jinjiang River basin.Results showed that under the same rainfall intensities（1.09 mm/min）,the amounts of runoff and sediment followed the order that bare landtwo-year-old tea gardenfour-year-old tea garden.The amount of runoff had directly positive correlated with that of sediment.The losses of pollution in runoff of two-year-old tea garden,four-year-old tea garden and bare land were listed below,TN： 461.29,129.38,107.86 mg/m2;NO3-N： 286.42,98.58,103.00 mg/m2,and more than 60% of the TN were lost through NO3-N;NH4-N： 48.67,16.19,4.42 mg/m2;TP： 34.71,16.47,23.88 mg/m2.The losses of pollution in sediment of two-year-old tea garden,four-year-old tea garden and bare land were listed below,TN： 379.28,44.81,747.16 mg/m2,which account for 25.72%～87.93% of the total losses;TP： 27.94,4.17,58.85 mg/m2,which account for 53.42%～68.36% of the total losses.Most of the nitrogen and phosphorous losses were through runoff in tea garden,whereas sediment in bare land.This study illustrated that tea plantation was beneficial on soil and water conservation;the longer plantation age tea garden can decrease more nitrogen and phosphorous losses to the water body.