Study On The Existing Form And The Loss Of Phosphorus In Eastern Section Of The North Shore Of Chaohu Lake Area

The effect of phosphorus loss on eutrophication in rich phosphate rock of Chaohu Lake can not be neglected,to find out the distribution of phosphorus,loss risk in the typical area of esposed area of phosphorus and the phosphorus leaching characteristics of phosphorus bearing rocks.125 samples were collected from northeastern of Chaohu with five different urban land-use types,the contents of phosphorus species were measured by a modified Hedley phosphorus fractionation,the data were analyzed based on Geostatistics method,then the risk assessment of phosphorus loss was conducted by phosphorus enrichment index and phosphorus index.At the same time,useing the phosphorus rock,we design the simulative leaching experiment of soil column.Giving the research results as follows:?1?The average content of TP was 561.94mg/kg,the average content of TP in the phosphate soil was the highest,reaching 1119.88 mg/kg,far more than the other four functional areas of the average content of TP.Generally,the phosphorus in the study area showed obvious spatial variation,the low-P fields appeared at the northern study area,and the high-P fields appeared at the southeast agricultural region and western mountains,the contents of phosphorus and total phosphorus in the surface soils around the rich phosphate rock are higher.The inorganic P remained the largest portion of TP and the content of available P was 135.44mg·kg^-1..The spatial variability of phosphorus species contents are greatly affected by the mode of urban land-use type,the contents of phosphorus and total phosphorus in the surface soils around the phosphate-rich layer can not be neglected.?2?The largest phosphorus accumulation rate of all land use types was HCl-P,the bio-available phosphorus in agricultural area had the highest phosphorus enrichment rate in all phosphorus forms except for H₂O-P,and agricultural activities had great influence on bio-available phosphorus.There is a high risk of phosphorus loss from the central Chaihuo Mountain to Pingding Mountain,Majianshan and southeastern agricultural areas,and there is a low risk of phosphorus loss from north of Pingding Mountain and the west of Caojia Mountain to Gui Mountain.Phosphorus rich mine have the highest risk of phosphorus loss and residential areas have the lowest risk of phosphorus loss.?3?With the increase of intermittent time,the cumulative release of phosphorus decreased first and then decreased.The release of phosphorus in each group was consistent with the 4 kinetic models,In addition to intermittent 5 and 7 days,the other groups of the distribution of total phosphorus roughly showed a downward trend from top to bottom.The critical value of Olsen-P leaching is 4.11mg/kg.The phosphorus leaching risk of some rock strata is comparatively larger.Relative to the soil,the rock's critical value of Olsen-P is relatively small.