Effect Of The Agricultural Usage Of Biogas Slurry On Wheat Yield, Quality And Environmental Quality Of Soil

Biogas slurry is a kind of liquid organic fertilizer, which is sealed by the raw material (human, animal manure and a variety of crop straw, etc.) after fermentation. It is rich in nutrients and biologically active substances with bio-fertilizers and bio-the double effect of pesticides. The rational use of biogas slurry can not only reduce the application of fertilizers and pesticides, the destruction of ecosystems and the environment, the production cost of agricultural development, but also improve the income of farmers, crop yield, crop quality, the soil environment. Thereby it could promote soil environment.In this study, the resource utilization of biogas slurry and agricultural production were combined. Biogas slurry anaerobic fermented with pig manure of large-scale pig farms, were used as fertilizer sources instead of chemical fertilizers. It was applied to conduct filed experiment of planting oil-seed rape in Ziyang City of Sichuan province on the hilly purple soil. Effects of biogas slurry on growing development, yield and quality of wheat, quality of soil were investigated under different application rates of biogas slurry with water and chemical fertilizer as controls. The appropriate application rate of biogas slurry in the production of wheat and the maximum capacity of biogas slurry that soil could bear were determined, thus to provide a theoretical basis for the scientific resource utilization of biogas slurry in agricultural production. The results of this study were as follows:1. Wheat yield and quality as indicators for the control of the scope of application of biogas slurryThe wheat field trial shows that, when the biogas slurry application rate was in the range of 2000kg/667m2 to 5000kg/667m2 (treatment 4 to 9), the yield and the nutritional quality of of wheat was the highest. When the biogas slurry application rate was in the range of 1500kg/667m2 to 4500 kg/667m2 (treatment 3 to 8), the contents of heavy metals under biogas slurry treatments were all significantly lower than that of conventional chemical fertilizer treatment. In addition, they were all in line with the corresponding limits of "Limits of contaminants in food" (GB2762-2005).Considering the effects of biogas slurry on the yield as well as quality of wheat, this study suggests that when the biogas slurry application rate was in the range of 3500 kg/667m2 to4500kg/667m2 (treatment 6 to 8), the yield of rape was the highest and the quality of rape was the best, the economic benefit of biogas slurry application was better.2. The heavy metal content of wheat grain as indicators for the control of the scope of application of biogas slurryAppropriate amount of biogas slurry application can improve the soil pH, thus to prevent soil acidification. When the biogas slurry application rate was in the range of 3000kg/667m2 to 5000kg/667m2(treatment 6 to 8), the contents of total nitrogen, alkali-hydrolyzable nitrogen, available phosphorus, available potassium, organic matter of soil and the contents of mineral elements in soil were all significantly higher than that of conventional chemical treatment. The contents of heavy metals in soil increased with the increasement of application rate of biogas slurry to varying degrees, but when the biogas slurry application rate was in the range of 1500kg/667m2 to 4500kg/667m2 (treatment 3 to 8), the contents of heavy metals in soil stayed at a low level.This study suggests that when the biogas slurry application rate was in the range of 3000kg/667m2 to 4500kg/667m2 (treatment 5 to 8), the soil fertility was high, the environmental quality of soil was better, the environmental benefit of biogas slurry application was better.To sum up, application of biogas slurry anaerobic fermented with pig manure of large-scale pig farms as fertilizer sources instead of chemical fertilizers to plant oil-seed rape on the hilly purple soil in Ziyang city of Sichuan province, considering the effects of biogas slurry on growing development, yield and quality of wheat as well as quality of soil, the appropriate application rate of biogas slurry in the production of wheat was in the range of 4000 kg/667m2 to 4500 kg/667m2.