中文摘要：

为了在东方 Horqin 砂土，中国， P 部分和 phosphomonoesterase 活动在土壤磷(P) 转变上估计无树平原造林的效果，在一个无树平原和邻近的 30-year-oldMongolian 松下面在二土层(0-5 厘米和 5-20 厘米) 被检验(Pinus sylvestris L。var。蒙古人集成通信适配器 Litv )P 缺乏的 semi-aridsandy 土壤上的种植园。除了在种植园下面的易变的器官的 P 与土壤深度是不变的之外，结果证明所有土壤 P 部分和 phosphomonoesterase 活动在两个地点与土壤深度减少了。与无树平原相对照，在蒙古的松种植园下面的土壤举办了 lowerphosphomonoesterase 活动和所有 P 部分的集中(与高山的一个例外) ，在全部的 P 的器官的 P 和帽子的更低的比例，和易变的 P 的更高的比例，在全部的 P 的高山 andFe-P。这些结果建议 P 转变主要发生在表土，并且通过崽秋天再循环的 P 是最重要的来源种可得到的 P。Mongolianpine 造林提高了器官的 P 和帽子的简历可获得性，同时减少的土壤 P 水池，显示森林地板和 P 授精的那保护是必要的维持蒙古的松种植园的持续工作。

英文摘要：

To assess the effects of savanna afforestation on soil phosphorus （P） transformations in eastern Horqin Sandy Land, China, P fractions and phosphomonoesterase activities were examined in two soil horizons （0-5 cm and 5-20 cm） under a savanna and an adjacent 30-year-old Mongolian pine （Pinus sylvestris L. vat. mongolica Litv.） plantation on a P-deficient semi arid sandy soil. The results showed that all soil P fractions and phosphomonoestcrase activities decreased with soil depth at both sites except that labile organic P under the plantation was constant with soil depth, In contrast to savanna, soils trader Mongolian pine plantation had lower phosphomonoesterase activities and concentrations of all P fractions （with an exception of Al-P）, lower proportions of organic P and Ca-P in total P, and higher proportions of labile P, Al-P and Fe-P in total P. These results suggested that P transformations mainly occurred in surface soils, and P recycled through litterfall was the most important source of plant available P. Mongolian pine afforestation enhanced the bioavailability of both organic P and Ca-P. simultaneously reduced soil P pools. indicating that protection of forest floor and P fertilization are necessary to maintain the sustainable functioning of Mongolian pine plantations.