摘要
磷素（P）在环境中的过量累积是导致农业面源污染的主要因素。论文以湖南省长沙县脱甲河农区小流域（52km2）和涧山河森林一农区小流域（50km2）为研究单元，基于人户调查资料和连续4a的流域把口站水文水质定位观测数据，采用物质流分析法，对比研究了亚热带丘陵区典型小流域P的收支平衡及流失特征。结果表明，农区小流域出口地表水总磷（TP）含量变化为0．03-0．68mg·L-1，平均含量为0．21mg·L-1，整体达到Ⅲ类水质标准；森林一农区小流域TP含量变化范围为0．01~0．35mg·L-1，平均为0．08mg·L-1，整体为Ⅱ类水质，表明森林一农区小流域地表水水质明显优于农区小流域。农区小流域P的环境滞留强度（32．0kg·hm-2·a-1）显著高于森林一农区小流域（20．6kg·hm-1·a-1），对环境影响更大。以2013年为例，农区小流域P的主要输入项为饲料，占53．1％，森林-农区小流域则以肥料为主，占53．0％；两个流域的P输出项都以植物和畜禽产品输出为主，均占总输出量的94．0％左右。控制小流域肥料和饲料投入、增加循环利用途径以及提高P利用率是当前减轻水体富营养化的有效途径。
Surplus phosphorus is a main source of non-point source pollution. Tuojia, a small agricultural watershed （52 km2） and Jianshan, a small forest-agricultural watershed （50 kin2）, located in Changsha County, Hunan Province, are taken as the case study. Based on the household surveys and 4-successive-year of observations of the phosphorus （P） flows at the terminal of river, substance flow analysis was used to quantify the budgets of P. Results showed that the concentrations of P in the agricultural ranged 0.03-0.68 rag-L ~, with the average 0.2 l mg. L-1, while the corresponding one in the forest-agricultural ranged 0.01-0.35 mg. L-1 with the average 0.08 mg-L-1. The surface water quality in the forest-agricultural watershed was obviously better than that in the agricultural watershed. The phosphorus surplus intensity in the agricultural watershed was apparently higher （32.0 kg. hm2. a-1） than that in the forest-agricul- tural watershed （20.6 kg. hm-2·a 1）, and thus had a greater effect on environment. In 2013, livestock feeding accounted for 53.1% of total P inputs in the agricultural watershed, while fertilizer contributed 53.0% in the forest-agricultural. Generally, the phosphorus from plant and animal products dominated in both watersheds, approximately accounting for 94.0% of the total. Thus, controlling the amount of P fertilizer and improving its utilization efficiency are good ways to mitigate the eutrophication in the study area.
出处
《自然资源学报》
CSSCI
CSCD
北大核心
2016年第2期321-330,共10页
Journal of Natural Resources
基金
国家自然科学基金(41171396
41201299)
国家科技支撑计划项目(2014BAD14B02)~~
关键词
磷负荷
磷收支平衡
入户调查
亚热带小流域
富营养化
phosphorus loading
phosphorus budget
household survey
subtropical small wa-tershed
eutrophication
