土地利用方式对洱海流域坝区土壤氮 磷 有机质含量的影响

为了解洱海流域土地利用对土壤养分的影响,调查研究了土地利用方式、种植模式,并研究了其对洱海流域坝区土壤w(TN)、w(TP)、w(OM)(OM为有机质)、w(olsen-P)(olsen-P为速效磷)和w(NO₃--N)的影响.结果表明:①流域坝区土壤中w(OM)、w(TN)较高,平均值为52.16和2.76 g/kg；w(olsen-P)较低,平均值为6.55 mg/kg.②对比农田、林地、裸地、园地4种土地利用方式,土壤中w(TN)、w(OM)、w(TP)、w(olsen-P)均呈农田>园地、林地>裸地的变化趋势.③种植模式对农田土壤养分影响有差异,水稻-大蒜模式下土壤的养分含量总体较高,w(TN)、w(OM)平均值分别为4.21、74.22 g/kg,是玉米-蚕豆模式的1.98、1.96倍；蔬菜模式土壤中w(NO₃--N)高达103.3 mg/kg,是水稻-蚕豆模式的37.29倍.④流域坝区农田土壤养分具有空间变异性,海东地区土壤中w(TP)和w(olsen-P)较高,分别为1.23 g/kg和11.48 mg/kg,是凤仪地区的2.16和2.15倍；上关-邓川地区w(TN)较高,为4.28 g/kg,是海东地区的1.63倍；w(OM)空间差异不明显(P>0.05).研究显示,流域坝区土壤氮、磷流失总量分别为686、241 t,主要贡献来自农田. 

Effects of Land Use on Soil Nitrogen,Phosphorous and Organic Matter Contents in Flatland of Erhai Lake Basin

Abstract:The effects of land use types and rotation patterns on the total nitrogen(TN),total phosphorous(TP),organic matter(OM),nitrate nitrogen(NO₃--N) and available phosphorus(olsen-P) content of soil from flatlands in Erhai Lake basin were investigated.The results showed that:1) The average TN and OM contents of the soil were at a high level,with 52.15 and 2.76 g/kg,respectively.In contrast,the olsen-P content was 6.55 mg/kg,which was at a low level.2) The TN,OM,TP and olsen-P contents of soil in different land use types showed a decreasing order:farmland>orchard,forest land>bare land.3) Soil nutrients were significantly influenced by rotation patterns.The soil nutrients in rice-garlic rotation pattern were relatively high,with TN and OM contents of 4.21 and 74.22 g/kg,which were 1.96 and 1.98 times those of the corn-fave bean rotation pattern,respectively.The NO₃--N content in vegetables rotation pattern was up to 103.3 mg/kg,which was 37.29 times that of the rice-fave bean rotation pattern.4) The farmland soil nutrients showed obvious spatial variability.The soil TP and olsen-P content in Haidong region were the highest among different regions,and were 1.23 g/kg and 11.48 mg/kg,which were 2.16 and 2.15 times those of the lowest in Fengyi region.The soil TN content in Shangguan-Dengchuan region was the highest,4.28 g/kg,which was 1.63 times that of the lowest in Haidong region.However,the OM content showed no significant spatial differences(P>0.05).5) The total losses of nitrogen and phosphorus were 686 and 241 t from flatland soil in Erhai Lake Basin,and farmland was the main contributor of land use types.