南方森林土壤磷的吸附与生化激活机制

Study on the mechanisms of phosphate adsorption and biochemical activation in the Southern forest soil of China.The main results obtained by the experiments of isothermal phosphate adsorption showed that the forest soil could adsorb large amount of phosphorus.Phosphorus could be adsorbed firmly by the soil,so it will decrease its availability.When the amount of phosphorus added in the soils was 600mg·kg-1, the amount of phosphorus adsorbed by soils was 451.2～550.8 mg·kg-1,its rate of phosphorus adsorbed was 75.2～91.8%.The maximum buffering capacity and the free energy of phosphate adsorption are regarded as important indexes to evaluate the phosphate buffering capacity of soils. Regression analysis revealed that the maximum buffering capacity and free energy of phosphate adsorption had close relation to chemical and physical properties of soils.They generlly had positive relation to the pH value,the amount of clay and hygroscopic water of the soil.But they had negative relation to the contents of organic matter,available phosphate and total phosphate of the soil. We can forecast the fertiphos requirement of soil according to the phosphate adsorption and buffering capacity. It is significant for rational application of fertiphos. Results also showed that tree root growth in soil can decrease phosphorus adsorption. Organic acids have a great effect on phosphorus mobilization with humic acid stronger than simple organic acids. Significant P mobilization is observed under additions of humic acid at 2.0 g·kg-1, and citric acid and tartaric acids at 4.0 g·kg-1 respectively. Therefore , fertiphos application with rational amount of organic acid can effectively increase the fertiphos efficiency by decreasing phosphorus adsorption in forest soil.

通过对南方丘陵山区主要森林土壤磷的吸附与生化激活机制的研究，了解土壤磷的吸附特性，阐明固定态磷的激活途径与方法，探讨土壤供磷能力，预测土壤磷肥需要量，研制高效的磷吸附抑制剂和刘效磷肥配方，为降低土壤磷的吸附、提高磷肥利用率开辟新的途径，为丘陵山区土壤合理施用磷肥提供依据。.