贵州中部喀斯特山区水稻田面水N、P浓度变化及污染评价

为了探讨喀斯特山区水稻土中N、P的迁移转化规律及对地表水环境的影响，选择贵州中部普定县喀斯特山区代表性的水稻土为对象，研究喀斯特山区水稻田面水中N、P浓度的变化及其与土壤中N、P含量的关系。结果表明：喀斯特山区水稻田面水中总氮(TN)浓度范围为1.39~15.81 mg/L，其中NH4+-N、NO3--N浓度分别为0.57~13.35 mg/L和0.15~1.37 mg/L，其浓度的变化与土壤中碱解氮含量有一定的正相关性；田面水中总磷(TP)的浓度范围为0.027~0.324 mg/L，其浓度变化与土壤有效磷含量有显著的正相关性。田面水中TN和NH4+-N浓度超过地表水Ⅴ类水体的标准限值，农田排水氮的迁移对周围地表水体质量会产生明显的影响。

Changes in Concentrations of N and P in Surface Water of Paddy Field and Its Pollution Assessment in Karst Hilly Areas

In order to explore the rule of N, P migration and transformation in paddy soil and its influence on the quality of surface water in Karst hilly regions of central Guizhou Province. The concentration of N and P in surface water of paddy field and its correlation with the contents of N and P in paddy soil were analyzed. The results showed that, the content of total nitrogen （TN）, ammonium nitrogen （NH4 ＋-N） and nitric nitrogen （NO3--N） in surface water of paddy field were 1.39-15.81 mg/L, 0.57-13.35 mg/L and 0.15-1.37 mg/L, respectively, which the concentrations of TN, NH4 ＋ -N and NO3--N were correlated with content of soil available nitrogen, in some extent. The concentration of total phosphorus （TP） was 0.027-0.324 mg/L, which the concentration of TP was significantly correlated with content of soil available phosphorus. The concentration of TN and NH4＋ -N in surface water of paddy field exceed the limits of the Class V water body, the nitrogen migration caused by farmland drainage from paddy field had a significant impact on the surrounding surface water quality.