Distribution characteristics of phosphorus in topsoil of Jiangsu

On the basis of relevant data from multi-target regional geochemical surveys in Jiangsu province,this paper presents the results of the latest study of the distribution of phosphorus in topsoil in the study areas and discusses the in-depth study of the results of the investigation and applied problems.The following has been preliminarily found: total phosphorus is of very uneven distribution in topsoil of the province and its content is very high on the surface; volcanic ash soil originating from basic rocks,fluvio-aquic soil and salinized soil are three major P-rich soil types in the province; the Olsen-P distribution is not completely controlled by total P and the Olsen-P concentration is 5 mg/kg in 85% of the topsoil in the province; the deficiency of Olsen-P is markedly superior to that of total P in topsoil.Data comparison indicates that: the land use pattern can directly affect the distribution of Olsen-P in topsoil; the Olsen-P content in the topsoil of grassland,shoals and forest is notably lower than that in others cultivated land; and regression analysis indicates that there is a pronounced positive correlation between total P and Olsen-P in topsoil samples from local places.