| The use of a large amount of phosphorus fertilizer has become an important loss source from farmland at the present agricultural production. So controlling phosphorus fertilizer is a significant target for non-point pollution management. Generally, the process of phosphorus transfer is closely related with the hydrologic process of drainage area. The loss of soil phosphor to water bodies of the groundwater and surface water mainly includes two ways:runoff and subsurface flow. The non-point phosphorus pollution could result in water environment's deteriorism. The phenomenon of water eutrophication significantly correlated with the loss of soil phosphor. Therefore, the studies of the process, mechanics and controlling measure on the loss of farmland soil phosphor to water bodies have been highly increased attentions from scientists over the world.In recent years, urban agricultural producing area safety problems cause more attention. XIN Chang Town located in Nanhui District, Shanghai City. It's phosphorus migrate transforms has urban agriculture's typical features. This paper research Nanhui orchard village domain range farmland soil, surface water and groundwater in different forms p time and space distribution law by the statistics and geographic information system and other methods. Observed rainfall events of the typical of non-point pollution demonstrations, analysis the migration patterns with rainfall phosphorus. It's provide the scientific basis for Shanghai plain urban agriculture agrichemicals content reduction technology and the agricultural product safety warning data. Study the main conclusions are as follows:(1) Orchard farmland soil Phosphorus distribution characteristics:the content of Total Phosphorus in soil distributed unevenly; low relatively content in soil distributed in the most area. Account for about two-thirds of area. It is mainly distributed in the central and the western of the orchard village. The variable coefficient and space distribution show that the study area of topsoil different positions exist difference, because of fertilization type, fertilizer use, fertilization habits and orchard management is not uniform.(2) Farmland soil seepage characteristics:dissolvable phosphate happening mainly in surface leakage. Because of the influence of irrigation or rainfall, following the increase of the soil depth, leakage intensity decrease. After heavy rainfall, total phosphorus concentration of surface soil with lower phosphorus gradually reduced. But phosphate phosphorus dissolved significantly increased after fertilized. The middle and bottom is gradually reduced. The content of dissolved phosphate were higher in research soil area, more than the Eutrophication phosphorus index (0.02 mg·L-1).The fertilizer group is more apparent, reached 0.7 mg·L-1. But the nearest underground water level is higher (usually in general about lm). So lots of fertilization is a large potential threat to the eutrophication of ground water.(3) Village domain spatial and temporal variation characteristics of groundwater P:the highest TP content is in the residential area groundwater. The second is beside the orchard village and river. In 18 sampling well, phosphorus are higher than 0.4 mg·L-1, ground water is belowV class standard. It's unfit for drinking. Meanwhile there are a lot of total phosphorus soluble organic phosphorus in the groundwater, more than 50%. In the residential area ground water, the Seasonal variation of the Total Phosphorus and Phosphate are likely. From January to March the content is low, the peak appear in April. And the content began to drop in April to May. During June to August phosphate content remain stable and slightly a rising trend. The changes of phosphorus pollution was consistent with seasonal changes.(4) Village domain spatial and temporal variation characteristics of surface water Phosphorus: in study area,Total Phosphorus content is high. It's more than V-class water phosphorus standards. It's severe eutrophication. There is no significant difference between the orchard village and residential areas. But except May, phosphorus loss seriously, there are significant differences in the average contents. It means the methods of land use have some influence to the distribution of ground water Phosphorus. Winter is more stable performance in orchard village Phosphorus seasonal change of the ground water. Spring gradually is increasing. In Summer and Autumn are gradually reduce. Dissolved phosphate in ground water accounted for the low proportion of the dissolved Total Phosphorus. The main form is the dissolved Organic Phosphorus.(5) Typical rainfall event characteristics of phosphorus output:heavy rain and heavy rainfall event twice phosphorus output present different change rule. Phosphorus loss is primarily dissolved phosphate in rainstorm events. In heavy rain event, phosphorus loss is primarily particle state phosphorus. Phosphate is main forms of phosphorus loss. Phosphor elements form and rainfall intensity, rainfall phosphorus concentration process lines influence the variation characteristics. In two rainfall event, phosphorus concentration process line variation amplitude obviously,lead to flow process line. In heavy rain cases, surface runoff sediment transport rate and the trend of the surface runoff is cardinally identical. But when it comes to heavy rainfall, their changes trend are basic disagreed.
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