三峡库区紫色土坡耕地小流域磷收支估算及污染潜势

为了解三峡库区磷收支情况，进行污染潜势评价，对三峡库区典型紫色土坡耕区新政小流域进行调查分析. 结果表明，新政小流域单位面积磷输入量为139.82 kg/(hm2·a)，输出量为 101.69 kg/(hm2·a).肥料磷输入是新政小流域磷输入的主要来源，占磷输入总量的72.26%；人畜排泄物磷是新政小流域磷的主要输出方式，占磷输出总量的56.01%；新政小流域磷损失负荷为18.26 kg/(hm2·a)，人畜排泄物损失磷是磷损失的主要形式，占磷损失总量的46.75%；磷盈余负荷为38.13 kg/(hm2·a)，高于全国平均值26.1 kg/(hm2·a).坡耕地磷污染潜势呈现，磷肥的过量施用是造成污染潜势的主要原因. 

Phosphorous Input-Output Budgets for a Small Watershed in Purple Soil Sloped Farmland in the Three Gorges Area and Its Pollution Potential

To understand the phosphorous input-output situation in the Three Gorges Area and to estimate pollution potential,the Xinzheng small watershed in a typical purple soil sloped farmland in the Three Gorges Area was investigated.The results indicated that the phosphorus input was 139.82 kg/(hm2·a) and the output was 101.69 kg/(hm2·a).Fertilizer was the main phosphorous input source,accounting for 72.26% of the total phosphorous input amount.The main output track of phosphorus was excreta from livestock and humans,accounting for 56.01% of the total phosphorous output amount.In this small watershed,the phosphorus loss load was 18.26 kg/(hm2·a).The primary phosphorus loss came from excreta,accounting for 46.75% of the total phosphorus loss.In addition,the phosphorus surplus load was 38.13 kg/(hm2·a) in this watershed,which was higher than the national average of 26.1 kg/(hm2·a).Therefore,phosphorus pollution potential appeared in this farmland.Excessive phosphorus fertilization was the main reason for this pollution potential.