Abstract:A long-term experiment (13 years) indicates that three type of organic manure can increase the content of soil organic matter in upland of red soil, but the rates vary. With the local traditional rate of manure application, the annual growth rate of soil organic matter is the highest in the farmyard manure treatment, followed by the green manure treatment and the straw treatment. The relation between accumulation of organic matter and quantity of organic manure applied is Y=Aebx, where Y stands for content of organic matter in the soil and X for quantity of organic manure applied. The primary factors affecting the accumulation rate are quantity and C/N of the organic matter applied. C/N of the organic matter has a major effect on the accumulation coefficient of organic matter of different organic manure source(kg OM/kg fertilizer).
The most important problems affecting increasing content of organic matter in red soil through application of organic manure are sources and transportation of organic manure, especially in hilly red soil areas. The results of the experiment indicate recycling straw as manure in the plots yet slightly increases organic matter content in the red soil, and also brings back most part of the potassium (>60 percent) absorbed by the crop to the soil, but at a low rate. Thereby, this measure can be taken as solution to the above-mentioned problems in farming practice.