Abstract: This experiment studied on the decay process and nutrition release regulars of green manure ploughed in cotton field(15-20 cm soil layer) and green manure were installed in nilong dilly bag． Green manure included winter 70 rye，winter rape，and hairy vetch． The results showed that: dry matter weight of green manure decreased significantly dring 0-43 days incubation，decomposing speed were most fast in the first three days， then more and more slowly． After 43 days incubation，decomposition rate of winter rape，hairy vetch and winter 70 rye at 81． 7%， 77． 5%， 62． 2%，and after 113 days incubation at 89． 6%， 89． 5%， 76． 2%， respectively． Nitrogen released fast in the first 21days，after 21 days incubation，N-mineralization rates of three green manure were all greater than 60%． Phosphorous released gently during the whole ploughing days，after 113 days incubation，P-mineralization rates of winter rape，hairy vetch and winter 70 rye at 89． 6%， 86． 5%， 75． 6%， respectively． Potassium released fast in the first 9 days，K-mineralization rates were more than 90% after 9 days incubation． Carbon released fast in the first 21days，after 113 days incubation，C-mineralization rates of winter rape，hairy vetch and winter 70 rye at 93． 4%， 91． 3%， 81． 9%， respectively． C /N ratio of winter 70 rye showed increasing tendency in the first 15days， from 22 to 36，while the other two breed had no significant change．

Key words: Winter 70 rye, Winter rape, Hairy vetch + ryegrass, Decomposition regular, Nutrient release characteristics

CLC Number: 

• S142