【摘要】 采用样地调查的方法研究江苏省东台林场3、5、11年生I 69杨根际、非根际土壤磷素特征。结果表明,滨海盐渍土或轻度盐渍土壤无机磷主要以Ca P形态存在,并且绝大部分是极难溶解的Ca10 P。有效磷在3、5、11年生I 69杨根际明显富集,且随林龄增大,富集率显著提高。根系对无机磷各组分的分布特征亦有明显的诱导作用,但Al P、Fe P、O P在3种林龄I 69杨根际、非根际土壤中均无明显变化。I 69杨根系的诱导作用还表现在对土壤中不同形态无机磷相互转化的作用,如伴随着根际Ca10 P的亏缺,根际Ca2 P、Ca8 P富集。多元回归分析和逐步回归分析表明无机磷各组分对植物有效性有明显差异,Ca2 P对有效磷贡献最大,其在根际的积累是根际有效磷富集的根本原因,Ca10 P也与有效磷关系密切,是植物的潜在磷源。更多还原

【Abstract】 The characteristics of inorganic phosphorus in the rhizosphere and nonrhizosphere soils under 3,5,11 year I69 clone stands were studied by means of investigating experimental sites and ecological sequential comparison in Dongtai forestry farm,Dongtai county,Jiangsu province.The results showed that in the soil developed on new coastal sediment,most forms of inorganic phosphorus were CaP of which insoluble Ca10P was the main form,approximately accounting for 90%.AvailableP(DAP) was accumulated clearly in the rhizosphere of 3,5,11 year I69 clone stands respectively,and the accumulating rates(RS)/S were increased with the stand ages of I69 clone.Poplar roots have the obvious induced influences on the distribution characteristics of soil inorganic phosphorus fractions.Ca2P was accumulated in the rhizospheres of 3 experimental stands,Ca8P was also accumulated evidently in the rhizospheres of 5,11 year I69 stands,whereas Ca10P was depleted clearly,but not in the rhizosphere of 3 year stand.There were no obvious differences in amounts of AlP,FeP,OP between rhizosphere and nonrhizosphere soils under 3 stands.Tree roots could induce transformation of various CaP fractions,indicating the accumulation of Ca2P and Ca8P corresponding with the depletion of Ca10P in the rhizosphere.Regression analysis indicated that Ca2P had the most contribution to DAP and its accumulation was the essential reason that the amount of DAP was much higher in the rhizosphere.Ca10P was also related to DAP and was the potential P source for plant growth.更多还原