Phosphorus accumulation characteristics and loss risk in vegetable garden soils of Shanxi Province

Risk of soil phosphorus loss was analyzed through phosphorus saturation degree (DPS), Mehlich3-P, Olsen-P and water-soluble phosphorus (Pw) accumulation to understand the status of soil phosphorus accumulation and loss as influenced by vegetable, soil type in different regions of Shanxi Province. Based on the results, total phosphorus, Pw, Olsen-P and Mehlich3-P of soil accumulate significantly, occurring in far greater amounts than crop need in Shanxi. Pw content increases with increased DPS, Olsen-P and Mehlich3-P content in surface garden soils. Furthermore, significant correlations (P<0.01) between Mehlich3-P and Olsen-P, Pw and Olsen-P, Pw and Mehlich3-P are found with respective correlation coefficients of 0.976 6, 0.923 2 and 0.962 0. Pw content increases rapidly when DPS is above 46.64%, Olsen-P above 81.88 mg·kg-1 and Mehlich3-P above 164.59 mg·kg-1. The critical loss indexes of the garden soils in Shanxi are therefore isolated as 46.64% for DPS, 81.88 mg·kg-1 for Olsen-P, 164.59 mg·kg-1 for Mehlich3-P and 8.05 mg·kg-1 for Pw. This study provides an important theoretical basis for phosphorus nutrient and environmental risk management of vegetable soils in Shanxi Province.