杉林土壤中各类磷化合物的数量和效应

QUANTITIES AND EFFECTS OF VARIOUS PHOSPHORUS COMPOUNDS IN SOILS UNDER CHINESE FIR PLANTATION

In this paper soils under Chinese fir plantation in the southern Anhui province were studied, bv means of fractionation of organic and inorganic phosphorus compounds in soils, selection of analytical technique for determining soil available phosphorus, and correlation of the above-mentioned items to site index or phosphorus content in current needle of Chinese fir. It turned out that the quantities of Al-P correlated significantly with both site index and P o in the current needle of Chinese fir as the limiting factors among various soil nutrients. The storage of organic-P in soil also correlated significantly with site index, of which the storage of active organic-P was the most important one. Bray il method Was - fied from 4 techniques for determining available-P as the better one for soil under Chinese fir pic ruction. Quantity of active organic-P could also be used as an index to assess soil nutritive conditions. The soil criteria of P supplying ability worked out here were much lower than that commonly used for farmland.