Spatial Distribution Chacteristics And Loss Risk Of Soil Phosphorus In Central Yunnan Lakes Basin

There are many lakes in Central Yunnan. The major lake basins are rich in phosphate rock resources at the same time. Due to the complex terrain of the area, high density of population, high land-use intensity and, multiple land-use patterns, the risk of Phosphorus loss risk is big. Since the1990s, The lakes of Central Yunnan have continued to face the serious situation about the development of eutrophication. People have continued to improve the degree of attention to environmental effects of phosphorus into the lakes. The study on space characteristics of soil phosphorus around Fuxian Lake, Xingyun Lake, Qilu Lake and Yangzonghai Lake and these lake basins dedication are less. Use the method of combining field investigation and office analysis, use Kriging interpolation method and statistical analysis to study spatial distribution characteristics and loss risk of soil phosphorus in lakes basin of Central Yunnan in this paper. The distribution condition of soil phosphorus with different land-use patterns in lakes basin of Central Yunnan has made the preliminary analysis.The following results were obtained.1. The analysis of323samples showed that soil phosphorus of the the central Yunnan Lakes region were at a high level and soil total phosphorus(abbreviated as TP in the context) and available phosphorus(abbreviated as AP in the context) were at a wide range. TP and AP in the study area were normal distribution after logarithmic transformation. The analysis of semi-variogram model showed that the spatial correlation both of TP and AP were moderate-intensity. TP was0.09～65.84g/kg, vary widely, and a mean of2.69g/kg. The variation coefficient of TP was253.53%as strong variability.43.03%of samples TP was>1.00g/kg (level I),7.12%of samples TP was0.80～1.00g/kg(level Ⅱ),12.38%of samples TP was0.60-0.80g/kg(level III),12.38%of samples TP was0.40～0.60g/kg(level Ⅳ),15.17%of samples TP was0.20～0.40g/kg (level V) 9.91%of samples TP was=0.20g/kg (level VI). AP was0.02-2169.75mg/kg, vary widely, and a mean of124.50mg/kg. The variation coefficient of AP was312.56%as strong variability. According to the classification standard of Lu Rukun, AP>20mg/kg was rich, AP<10mg/kg was deficiency. Then rich region accounted for20.74%in lakes basin of Central Yunnan, and the region up to500-2169.75mg/kg accounted for8%. TP and AP were in the region of large amplitude.2. Kriging interpolation results showed that the spatial distribution of soil phosphorus was banded and lumpy mosaic distribution. High value area of TP (>5.57g/kg) were mainly distributed in the periphery of Fuxian Lake and Xingyun Lake, and to to both sides gradually reduce. The highest value areas (40.00-65.84g/kg) were in hat Tianshan Mountains Chengjiang; Low value areas (≤0.40g/kg) were mainly in the south of Qilu Lake and near Yangzonghai Lake. Distribution of TP and AP was the consistency of the trend.3.The differences of soil phosphorus were prominent in different regions in lakes basin of Central Yunnan. The overall spatial features of phosphorus-enriched area and non-phosphorus-enriched area were got by Kriging interpolation maps. Phosphorus-enriched areas(>5.57g/kg)were smaller but a wide rang where soil phosphorus content was very high, up to65.84g/kg, only9.60%of oil samples of TP content of more than5.57g/kg, its high phosphorus content had a greater threat to water security of river and lake; non-phosphorus-enriched areas were larger where soil phosphorus was low,83.28%of the sample less than the average TP2.69g/kg and had hardly a threat to water security of river and lake on river.4.There was greater relevance at the spatial distribution of soil phosphorus, vegetation and land-use patterns. From the content level of TP and AP, the order was phosphate> shrub> grassland>woodland. So we should focus on governance phosphate.5.We could use of method of soil phosphorus leaching "mutation" to evaluate the risk of leaching loss sensitivity of soil phosphorus. The preliminary results showed that AP content of68.71mg/kg can be used as boundaries of soil phosphorus loss sensitive. And7%of the tested soil exceeded the boundaries. Then draw the map of leaching loss sensitivity of soil phosphorus, and find sensitive area of phosphorus loss almost in the phosphate ore zone and its vicinity.In this paper, in view of the wide range of phosphorus-enriched area, serious risk of phosphorus loss and huge influence of soil phosphorus to lake environment, so the management of the phosphate ore should be put in an important position when we begin to plan to the land-use planning and non-point source pollution control.