三峡库区紫色土坡耕地小流域磷收支估算及污染潜势

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

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.

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/（hm^2·a） and the output was 101.69 kg/（hm^2·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/（hm^2·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/（hm^2·a） in this watershed,which was higher than the national average of 26.1 kg/（hm^2·a）.Therefore,phosphorus pollution potential appeared in this farmland.Excessive phosphorus fertilization was the main reason for this pollution potential.