Effects Of Different Soil Covering On Soil Active Carbon And Citrus Fruit Yield Quality,Nutrient Concentration Of Citrus

The change of soil organic carbon component has an important effect on the soil nutrients absorption and plants utilization.Soil mulching in orchard can effectively affect the microclimate condition of farmland,to protect soil structure and regulate soil hydrothermal conditions,to promote crop growth and increase crop yield.This paper focus on the soil active organic carbon components,by analyzing the variations of soil active organic carbon components under different coverage modes,to explore the relationships among soil active organic carbon components,soil fertility particularly nutrients availability,citrus nutrient,fruit yield and quality.The purpose of this study is to provide basis and technical support for improving soil fertility,nutrient utilization,fruit yield and quality in citrus orchards.The main results are:(1)The application of citrus special compound fertilizer with different covering modes can increase the concentration of total organic carbon,microbial biomass carbon and water soluble organic carbon in surface and subsurface soil layer,especially the increases of rice and wheat straw mulching of were more than that of plastic film mulching and grass mulching,such as the rice straw mulching with 37.5% and 50% of local nutrient use dose in Hunan experiment and wheat straw mulching of 10kg/plant and 15kg/plant in Hubei experiment.(2)The increased rates of soil available nitrogen and potassium concentration by rice and wheat straw mulching were more than that of grass and plastic film mulching,particularly the rice straw mulching with 37.5% of local nutrient use dose in Hunan experiment or wheat straw mulching of 15kg/plant.Plastic film mulching raised concentration of soil available phosphorus more than the others.(3)The increased rates of leaves total nitrogen and total phosphorus concentration by grass mulching and plastic film mulching were more than that of crop straw mulching,while increased rates of citrus fruit nitrogen,phosphorus and potassium concentration by rice and wheat straw mulching were more than that of plastic film mulching,Particularly the rice straw mulching with 37.5% of local nutrient use dose or wheat straw mulching of 15kg/plant.And the concentrations of leaf and peel potassium were strongly correlated with soil microbial carbon and total organic carbon.(4)The fruit yield were raised significantly by the rice straw mulching with 37.5% of local nutrient use dose or wheat straw mulching of 15kg/plant.And the fruit yield,color and the ratio of total soluble solids to total acid were positively correlated with some soil active organic carbon components in Hubei experiment.