落叶松根限土壤磷的有效性研究

野外用剥落法采集落叶松（Larix gmelini）根际土与非根际土，分析P浓度的变化，结果表明，落叶松根际土与非根际土全P浓度无明显差异，但根际土有效P却明显高于非根际土，12年生时根限土有效P增加12.6％，40年生时增加23.4%,表明落叶松根限对土壤中的P具有活化作用，落叶松根限土无机P各组分与非根际土亦有差异，表现出根际土O－P低于非要际土，Al-P,Fe-P,Ca-P和NH4Cl-P则高于非根际土的趋势，落叶松根限土的pH低于非根际土，但落叶松根限并未发生明显酸化，落叶松要际有效P与pH变化相关不显著。

Soil P availability in larch rhizosphere

Soil samples were collected from the rhizosphere and non rhizosphere of larch( Larix gmelini ) stand by exfoliation method, and the variation of P concentration was analyzed. The results show that there was no significant difference between total P concentrations in the rhizosphere and the non rhizosphere soil,while the concentration of available P in rizhosphere soil was significantly higher than that in the non rhizosphere soil.The concentrations of available P in rhizosphere 12 years old and 40 years old larch rhizosphered by 12.6% and 23.4% respectively,indicating that larch roots had the effect of mobilizing soil phosphorus.The components of inorganic P in rhizospheric soil were different from those in non rhizospheric soil.The concentration of O P was lower,and the concentrations of Al P,Fe P,Ca P,NH 4Cl P were higher in the rhizosphere.The pH of rhizospheric soil was lower than that of non rhizospheric soil,but no further acidification was observed.There was no close relationship between pH variation and available P concentration in larch rhizosphere.