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.