Abstract:

In order to promote the planting of winter green manure in North China,a long-term field experiment was adopted,and the winter idle field was used as a control.Four winter green manure treatments were set up,Orychophragmus violaceus,Viciavilosa Roth,Lolium perenne L.and Brassica campestris L..The effects of different winter green fertilizers on soil organic phosphorus and phosphorus content and corn phosphorus absorption were studied.The results showed that in the past 7 years of different winter green manure treatments,the change trend of soil total phosphorus and available phosphorus content was the same.Compared with other treatments,vetch increased the soil total phosphorus the most,with an average annual growth rate of 8.07%,winter rape increased soil availability compared with other treatments.The phosphorus content was the most,with an average annual growth rate of 48.34%.Different winter green manures and spring corn rotations had different effects on the organic phosphorus content of various forms in the soil.In 2019,the highest active organic phosphorus content was ryegrass treatment and winter rape treatment,both of which were 12.64 mg/kg;moderately active organic phosphorus content the highest was the winter rape treatment(41.64 mg/kg),the medium-stable organic phosphorus content was the highest in the ryegrass treatment(18.73 mg/kg),for the high-stability organic phosphorus,the winter rape treatment was significantly higher than other treatments.The treatments of February orchid,vetch and ryegrass were significantly lower than the treatments of winter fallow and winter rape;the rotation of winter rape and spring maize could promote the conversion of organic phosphorus to active and medium active organic phosphorus in the soil.After 7 years of winter green manure,the phosphorus content(0.39 mg/kg)of corn kernels treated with winter rape was the highest among the treatments.The order of correlation coefficients between the phosphorus content of corn grains and various forms of organic phosphorus was MLOP(0.952^**)>LOP(0.816^**)>MROP(0.122)>HROP(-0.064).

Key words: Spring corn, Winter green manure, Rotation, Organic phosphorus form, Organic phosphorus availability