亚热带丘陵区流域不同土地利用系统磷素径流输出特征

Runoff Phosphorus Discharge from Different Land Use System in Subtropical Hilly Areas

土地利用的环境影响是目前生态系统研究中的重要课题 .以位于亚热带低山丘陵地区的安徽省宣城市梅村中 2个相邻的支流域为实例 ,研究了具有不同土地利用结构的农 林生态系统地表径流水的磷素含量和输出 .结果表明 :林地 水塘 农田 村庄系统水溶性磷 (DP)含量 林地 水塘系统DP含量和林地 农田系统DP含量 ,后二者间没有显著性差异 ;林地 水塘 农田 村庄系统悬浮泥粒结合态磷 (PAP)含量 林地 农田系统PAP含量 >林地 水塘系统PAP含量 ,三者存在显著性差异 .总磷的输出量为 :林地 水塘 农田 村庄系统 林地 农田 >林地 水塘系统 .土地利用类型和结构对磷素输出有明显影响 ,村庄的存在显著地影响下游的水质 ,农田 (水稻田 )显著地增加悬浮颗粒和颗粒含磷的输出 .流域磷素主要是随土壤泥粒的流失而输出 ,在 3个系统中磷素的含量都以PAP的含量为主 ,占水中全磷量的 73 %～ 99% ,平均为 90 % .流域 3种土地利用系统地表径流水中的PAP的含量(PAP <40 0mg/L时 )均与悬浮泥粒的含量有一定的线性相关关系 ,而只有林地 水塘 农田

The environmental effect of land use becomes one of the most important issues in ecosystem research. This study on phosphorus in runoff was conducted in two contiguous sub watersheds with three land use types, which located in Meicun watershed of Xuancheng County, Anhui Province. The sub watersheds differed in land use, but had similar soils and hydrology. The results showed that the runoff dissolved phosphorus (DP) and particulate associated phosphorus (PAP) concentration of forest pond paddy village system was the highest among the three land use systems. There was no significant difference between DP of the forest pond system and forest paddy system. However, the PAP and TP of forest paddy system was higher than that of forest pond. The rank of the DP、PAP and TP discharges was wholly same with that of the PAP concentration. About 90% of TP was discharged with the particulate soil. There was a significant linear relationship between the concentration of PAP and the particulate of runoff in three land use systems. But only in the forest pond paddy village system existed a logarithm linear relationship between DP and PAP concentration.