Soil N and P Loss in Slope Farmland of Dianchi Watershed
ZHONG Xiong;ZHANG Li;ZHANG Naiming;NIAN Fuzhao;JIA Guangjun;YUE Xianrong;XIA Yunsheng;Yunnan Agricultural University;Yunnan Engineering Laboratory of Soil Fertility and Pollution Remediation;
The present study aimed to reveal the effects of intercropping on soil runoff and lateral seepage nitrogen(N),phosphorus(P)loss in different types of slope farmland.A runoff and leaching simulating experiment was conducted,different types of soil(red soil and purple soil)and slopes(8° and 15°)and planting patterns maize(Zea mays L.)/soybeans(Glycine max L.)intercropping and mono-maize and mono-soybeans)were designed,the changes of N and P concentrations in runoff and lateral seepage under the influence of various factors were analyzed.The results showed that:(1)In the case of the total nitrogen(TN)and total phosphorus(TP)of runoff:under different slope in red soil,compared with mono-soybean,intercropping has different reduction effect on TN,the reductions were 27.5% and 30.8%,respectively,and the TN under intercropping was the lowest,which was 0.75 mg/L at the slope of 8°.Under the slope of 8°in purple soil,compared with mono-soybeans and mono-maize,the reduction of intercropping on TN of runoff was more obvious,and the reductions were 97.8% and 89.8%,respectively.Compared with mono treatment,intercropping had the different reduction on TP of runoff.However,the TP of runoff increased fromthe slope of 8° to 15°.(2)For the lateral seepage TN,TP,under the slope of 8° and 15°in the red soil,compared with mono-maize,intercropping had a greater reduction of the lateral seepage TN,which had 87.9% and 86.8% reduction,respectively,as well as the lowest concentration of TN was 2.91 mg/L at 8°;under the slope of 8° and 15° in purple soil,the reduction of intercropping on TN of lateral seepage were 50% and 80%,respectively.Compared with mono-maize,intercropping also had the different reduction on TP of lateral seepage;and the TP under the slope of 8° in red soil of intercropping was the highest with 0.25 mg/L,and the TP under the slope of 15° red soil of intercropping was the lowest with 0.07 mg/L.The output of N and P in soil was different under different slope treatments and the total loss of N and P in runoff or lateral seepage would increase with the slope increasing.In conclusion,the maize/soybean intercropping system had a certain effect on the reduction of N and P concentration in the runoff and lateral seepage.For red soil and purple soil,the reduction of the loss of N and P in the soil of slope farmland might be different because of their physicochemical properties.Therefore,controlling the loss of N and P in slope farmland should consider all kinds of factors,which is of great significance to protect the water environment of Dianchi Watershed.
【Fund】： 国家自然科学基金项目(41161041 41561057);; 院士专家工作站项目(2015IC022);; 云南农业大学土壤资源利用与保护省创新团队开放基金项目(2015HC018)
【CateGory Index】： S158
【CateGory Index】： S158