Abstract:

【Objective】 The aim of the study was to develop an index to assess the environmental risk of P loss potential in vegetable soils with chronic difference of plantation in the suburbs of Changsha. 【Method】 Chemical methodology was used to study soil phosphorus status and the relationships between available P in soil and potential soil leaching P. 【Result】 The results showed that there was a significant linear relationship between Olsen-P and CaCl2-P or P concentration in soil solution. Olsen-P increased sharply when either CaCl2-P or P concentration in soil solution reached a certain level. It was confirmed that 80 mg•kg-1 of Olsen-P was the critical value of soil P leaching in the vegetable soil. P leaching probability over the critical was assessed by GIS and indicator kriging and four secondary risks of phosphorus leaching loss were defined. In the area with vegetable cropping for over 30 years (Chenjiadu) and 10-15 planting years (Huangxingzhen), the indices of phosphorus leaching loss risk were 3 and 2.93, respectively. These two areas belonged to strong secondary of risk of phosphate leaching loss. In the new vegetable planting field less than 2 years (Ningxiang), the index was 0.06, which was almost no risk of phosphorus leaching. 【Conclusion】 In vegetable soil in the suburban region of Changsha, the phosphorus leaching peotential is high and the phosphorus leaching loss is related to chronic length of vegetable cropping.

Key words: vegetable soil, P leaching criterion, P leaching probability, risk of phosphorus leaching loss