徐淮地区石灰性土壤磷素固定的研究

STUDY ON THE PHOSPHORUS FIXATION OF CALCAREOUS SOILS IN XU-HUAI DISTRICTS

用化学和物理化学的方法研究了纯CaCO_3固磷机制和特性。结果表明,随着起始磷浓度从低(0—10ppm P)到高(>10ppm P)变化,CaCO_3与磷先后发生吸附、沉淀反应,CaCO_3对磷具有很强的固定作用。徐淮地区石灰性土壤(黄潮土)固磷机制和特性的研究指出:起始磷浓度较低(0—200ppm P)时,以粘粒固定作用为主,CaCO_3的沉淀怍用不明显;起始磷浓度较高(>200ppm P)时,则粘粒与CaCO_3同时起作用,其中CaCO_3和磷之间的沉淀反应非常突出。石灰性土壤的固磷量和固磷强度均较高。

The fixation of phosphate by pure CaCO_3 was studied. The results indicated that at lower initial phosphorus concentrations, the phosphorus was mainly adsobed on CaCO_3 and at higher concentrations, precipitations occurred, and a large amount of phosphorus could be fixed by CaCO_3. The fixation of phosphorus by calcareous soils was then studied. The results indicated that at lower range of phosphorus concentrations (0—200 μgP/ml), clay played a major role in fixing phosphorus, while at higher concentrations (>200 μgP/ml), CaCO_3 became important. Thus it is showed that calcareous soils have high fixation power of phosphorus.