Effects of application of manure on soil fertility

Effects of manure application rates on crop yield and soil fertility were studied on a five-year field experiment in an aquic brown soil. The results indicate that the manure application plays an essential role in increasing and stabilizing yield. Contents of total C, total N and total P are decreased in the control treatment while total K is not inceased. Contents of available P, available K, organic carbon and total phosphorus are increased significantly with the manure application. Soil alkali-hydrolyzed nitrogen content is decreased by 9.19 mg/kg in five years under the low manure rate which shows that the demand of nitrogen uptake could not be met, while that under the moderate manure rate is slightly increased. Content of alkali-hydrolyzed nitrogen is significantly increased and a positive total N balance is observed at the high manure rate.