Impacts Of Green Manure Restoration And Fertilizer Reduction On Soil Nutrient And Maize Yield

Green manure is one of the important measures to improve soil quality.The paper studied the impacts of green fertilizer restoration and fertilizer reduction on maize yield and soil nutrient status in brown soil.A total of 6 treatments were carried out:CK(Winter fallow-Maize);T1(Chinese milk vetch-Maize);T2(Board beanMaize);T3(Rape-Maize);T4(Smooth vetch-Maize);T5(Ryegrass-Maize).When maize is planted,CK is routinely fertilized.All the green fertilizer harvested from T1－T5 was returned to the field,and the amount of fertilizer applied was 70%of that of conventional fertilization.Combined with the effects of different green fertilizers on soil physical and chemical properties,soil enzyme activities,nitrogen metabolism enzyme in maize plants and maize yield,the following results were obtained:(1)The total nitrogen content in the soil returned from green manure was significantly higher than that treated by CK,with an increase range of 12.41 to 26.90%.Soil organic matter content can be increased by returning green manure to the field.The soil treated by T3 overturn rapeseed had the highest organic matter content,which is 15.96%higher than CK.(2)Compared with CK,the activities of urease,invertase and cellulase in soil can be increased by green manure,the maximum increase was 214.26%,363.78%and 382.40%respectively.The activity of polyphenol oxidase in green manure returning soil decreased,the maximum decrease was 67.82%.In the early stage of green fertilizer returning to the field,the total activity parameters of soil enzymes treated with T3 were higher,ranging from 4.78 to 5.20.The total activity parameters of soil enzymes treated by T5 ryegrass overturning in late stage were higher,ranging from 4.98 to 5.18.The total activity parameters of soil enzyme were significantly correlated with soil urease,sucrose enzyme and cellulose enzyme.(3)The activity of nitric acid reductase(NR)and glutamine synthase(GS)in functional leaves of maize was significantly increased by green manure,which was 1.19～2.55 times and 0.93～1.59 times of CK treatment,respectively.Increasing the nitrogen metabolism enzyme activity of maize plants is beneficial to the absorption of nitrogen by maize plants.(4)T2 vicia faba overturning treatment significantly increased the yield of maize compared with CK by 6.8%.There was no significant difference in the yield of corn treated with other fertilizer reduction and green manure and CK.To sum up,reducing the application of 30%of the fertilizer after returning the green manure will not reduce the soil available nutrients and corn yield,and increase the soil organic matter and total nitrogen content.It shows that green manure can replace some fertilizers to provide nutrients for the growth of crops,and it was the best to improve soil nutrient in rapeseed and ryegrass fields in Yangtze-Huaihe region of Anhui.