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为了解喀斯特山区小流域不同农作行为下的地表径流水质量变化,采用相关分析、逐步回归、通径分析和聚类分析等方法,对贵州中部喀斯特山区普定县猫洞小流域(低复种旱作区、高复种旱作区和高复种复合农作区)的径流水进行了采样分析。结果表明:在长期不同农作行为的影响下,3类农作生态区地表径流水中的化学组分有明显不同,从低复种指数旱作区、高复种指数旱作区到高复种指数复合农作区,地表径流中的NO3-、NH4+、PO43-、SO42-的含量和高锰酸钾指数依次增大,均呈显著上升趋势;经相关分析、逐步回归及通径分析,农用地地表径流中NO3-、PO43-、NH4+含量和高锰酸钾指数一定程度上受土壤有机质、氮磷含量和植被变化的影响;主成分聚类分析,第1类型即低复种旱作区,指标达Ⅰ类水体的标准,水质量良好;第2类型以高复种旱作区为主,兼有高复种复合农作区,NH4+、PO43-含量部分达Ⅱ～Ⅲ类水体的标准,高锰酸钾指数达Ⅰ～Ⅱ类水体的标准,水体质量受到一定程度的影响;第3类型即高复种复合农作区为主,NH4+、NO3-部分超地表Ⅲ类水体标准,PO43-含量部分达Ⅱ～Ⅲ类水体的标准,高锰酸钾指数达Ⅰ～Ⅱ类水体的标准,地表径流水质在Ⅱ～Ⅲ类水体标准,部分指标超Ⅲ类水体标准,水体已受到污染。
In order to understand the variation of surface runoff water quality under different farming behaviors in the small watershed of Karst mountains, the correlation analysis, stepwise regression, path analysis and cluster analysis were used to analyze the changes of surface runoff water quality in the small-scale catchment Runoff areas, high-cropping areas and high-cropping areas) were sampled and analyzed. The results showed that under the influence of long-term different farming behaviors, the chemical composition of surface runoff water in three kinds of agro-ecological areas were significantly different. From low-acreage index dry-farming area, high-respec- tive index dry-farming area to high multiple-acreage composite crop The content of NO3-, NH4 +, PO43- and SO42- and the potassium permanganate index in the runoff and surface runoff increased in turn, all showing a significant upward trend. Through correlation analysis, stepwise regression and path analysis, the surface runoff The content of NO3-, PO43-, NH4 + and potassium permanganate index were affected to a certain extent by soil organic matter, nitrogen and phosphorus content and vegetation change. The main components were cluster analysis, The second type is dominated by high multiple cropping area, and the second one is high standard multiple cropping area. The content of NH4 + and PO43- reaches the standard of Ⅱ ~ Ⅲ water body. The potassium permanganate index The water quality was affected to some extent by the standard of Ⅰ ~ Ⅱ water bodies. The third type was the high multiple cropping area, the NH4 + and NO3- partly exceeded the surface water standard of Class Ⅲ, and the PO43- content reached Ⅱ ~ Ⅲ Class of water standards, potassium permanganate index of Ⅰ ~ Ⅱ class water Standard, runoff water quality class Ⅱ ~ Ⅲ water standards, some indicators superclass Ⅲ water standards, the water is polluted.