山西省菜园土壤磷素积累特征及流失风险分析

为了解山西省不同区域菜园土壤磷素积累以及流失情况, 本文分析了菜园土壤磷饱和度(DPS)、Mehlich3-P、Olsen-P与水溶性磷(Pw)的积累特征.结果表明: 山西各地菜园土壤4种磷素(土壤全磷、水溶性磷、Olsen-P和 Mehlich3-P)积累明显, 已经远远超过作物需求量; 土壤表层水溶性磷含量随着土壤磷饱和度(DPS)、Olsen-P、Mehlich3-P含量的增加而增加; 且Mehlich3-P与Olsen-P、水溶性磷与Olsen-P、水溶性磷与Mehlich3-P之间具有极显著相关性, 相关系数分别为0.976 6、0.923 2、0.962 0 (P<0.01); 当磷饱和度大于46.64%、Olsen-P大于81.88 mg·kg-1、Mehlich3-P大于164.59 mg·kg-1时, 水溶性磷含量上升幅度迅速增大, 由此将土壤磷饱和度为46.64%、Olsen-P 为81.88 mg·kg-1、Mehlich3-P为164.59 mg·kg-1和水溶性磷为8.05 mg·kg-1初步确定为山西省菜园土壤磷素流失的临界值.该结果将为探讨山西农田土壤磷素的养分管理和环境风险评估提供重要的理论依据.

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.