Effects Of Decomposition Regularity Of Green Manure Crops After Returning On Soil Fertility And Maize Yield

Alfalfa and sweet clover are the main green manure and forage grass crops in the Northeast. The purpose of study made sure that the decomposition regularity of alfalfa and sweet clover after turning over and the effect of soil fertility and maize yield as green manure after turning over. Development of major grain producing areas in the Northeast green manure crops to provide technical and theoretical support.The field tests and the indoor stimulation experiments were carried out in Administration of Agriculture Sideline Production Site of Fuyu Directly under the Regional Military Command of Shenyang of Fuyu county in Heilongjiang Province from 2008 to 2010.The decomposition regulation of dry matter and the mineralization regulation of N, P and K of alfalfa and sweet clover after turning over have the same tendency. The decomposition rate is proportional to temperture, so the fastest times between July and August. The K mineralization rate of two green manures were more than 96% in the first year. The dry matter decomposition of alfalfa and sweet clover were 87.54%,90.18% in two years, and C N P and K mineralization rate of alfalfa were 88.91%,94.45%,84.12% and 99.72% in two years, C N P and K mineralization rate of sweet clover were 88.94%,85.52%,83.15% and 99.82% in two years, respectively.Corn alfalfa and sweet clover rotation between the species which can increase soil organic matter content of treatment and improve the most is between 3:1 kind of corn sweet clover rotation. Changes in soil available nitrogen in all treatment generally showed slow increasing in the corn growing season, and after corn harvest until the second year spring had gradually increasing trendency. Each experiment with soil available nitrogen content was significantly different, and corn and alfalfa 2:1 treatment was higher than others,118.0mg/kg,and the largest increasing was corn and alfalfa 2:1 treatment,19.8mg/kg. Each experiment with Available phosphorus content had significant difference with CK and in basically the same with available nitrogen. The soil available phosphorus content of corn and alfalfa 1:1 treatment was higher than others,35.5mg/kg, and the largest increasing was corn and alfalfa 1:1 treatment, 10.1mg/kg.After turning over green manure, the available K content was generally fast in the whole growth, but had no significant increasing through the winter. Compared with the start of the trial, the available K content of each treatment were increased significantly, corn and sweet clover 1:1 treatment was higher than others, 206mg/kg, corn and alfalfa 3:1 was the largest of which 55.6 mg/kg, an increase of 37.0%.The intercropping of maize and green manure had a significant improvement in the growth and average per unit status of maize. The order of intercropping maize and alfalfa yield was 47.1%, 33.5% and 23.3%, and the order of intercropping maize and sweet clover yield was 38.5%,26.6% and 22.1% according to the width proportion from small to large.