artifical improvement of soil fertility in a regraded forest ecosystem by using municipal sewage sludge.
城市污泥对退化森林生态系统土壤的人工熟化研究。
in this area, improvement of soil fertility for terrace should start from adding n and p.
该地区梯田土壤的培肥措施应从增氮、补磷的角度出发;
the improvement of soil fertility could make the humification degree of free humus in soil and its complexes decrease, and furthermore, result in type change.