Studies On Phosphorus Status And The Risk Of Phosphorus Leaching In Vegetable Soils

Field sampling survey, soil sample analysis and lab soil column leaching simulated experiments were carried out to study the status of phosphorus and its fraction and distribution characteristics, the effects of different phosphorus fertilizers applied on phosphorus leaching as well as the assessment of phosphorus leaching risk in Fuzhou suburb vegetable soils. The results were listed as follows: 1 Fraction and distribution characteristics of phosphorus in vegetable soils1.1 The content of total P in 0-20cm layer of vegetable soils was 0.57-6.4g/kg, with an average of 2.22g/kg. According to the soil phosphorus classification standard, about 77.3% total P concentrate on extremely high-level (>1.00g/kg); Total P in soils mainly occurred in the form of inorganic P, the content of which in 0-20cm layer was 0.43-5.28g/kg, the percentage of inorganic P to total P was 84.0%; The content of Olsen-P in 0-20cm layer was 63.1-630.1mg/kg, with an average of 273.3mg/kg, all of them surpassed 60mg/kg. It was indicated that phosphorus enrichment in vegetable soils was serious.1.2 The contents of soil total P, inorganic P, organic P and Olsen-P decreased rapidly with the soil depth increased. The proportion of inorganic P to total P decreased while organic P increased with the soil depth increased, which showed that the organic P was easier to move and leach.1.3 Inorganic P mainly occurred in Al-P, Fe-P, O-P, which form about 90% to inorganic P, while the amount of Ca-P was lower, only about 10% to inorganic P; The contents of all the inorganic P forms decreased with the soil depth increase.1.4 The concentration of total P (TP) and dissolved P (DTP) in groundwater of vegetable soils investigated were 0.075-0.180mg/L and 0.035-0.125mg/L, with the average of 0.126mg/L and 0.080mg/L. About 80% of TP and 86.7% of DTP were...