Preparation Of Nutrient Composite Soil By Using Biogas Residue

Biogas residues produced by biogas engineering are abundant, and its nutrient components can be used for preparation of nutrient composite soil, in order to avoid its environmental pollution. Biogas residue was composed of various kinds of nutrient materials and organic compounds, such as organic matter, nitrogen, phosphor, potassium. Using biogas residue as raw material to prepare nutrient soil can not only consume a large amount of biogas residue to avoid secondary pollution, but also realize the reutilization and resourcification of biogas residue.The nutrient materials in biogas residue are beneficial to crops. Preparation of nutrient soil by using biogas residue is a direct way to supply nutrient to flower and plant. Analysis showed that biogas residue raw material, sawdust, bone meal consist more nutrient materials than black soil in northern China and red soil in southern China. Using biogas residue combined with red soil in southern China may be preparing a high nutrient content of nutritional soil.Different ratios of biogas residue to organic compounds were used to prepare nutrient soil. At a ratio of biogas manure:sawdust:red soil:bone meal was6:2:20:1, the nutrient composite soil has a higher level of nutrient. The parameters of the nutrient composite soil are that organic matter content was43.26g/kg, total nitrogen content was11.33g/kg, total phosphate content was0.67g/kg, ammonium nitrate nitrogen content was1.65mg/kg, available phosphate content was57.86g/kg, pH was7.46, water content was9.84%, bulk density was1.09g/cm3, specific gravity was2.38g/cm3, and porosity was54.25%.Nutrient composite soil was prepared under anaerobic fermentation and aerobic fermentation. Both ways can improve the nutrient content of the nutrient composite soil. The results indicate that the fermentation is beneficial to improve the nutrient of prepared soil. Anaerobic fermentation is better than aerobic fermentation, also when the fermentation time at20to30days anaerobic condition has higher nutrient, at40to50days aerobic fermentation has higher nutrient.Biogas slurry with different concentration was mixed with sawdust and red soil to the ratio of2000(v/ml):500:2000and though an anaerobic fermentation with60days. The result shows that the nutrient composite prepared by concentrated biogas slurry had higher nutrient content than liquid biogas slurry. At the fermentation time of20-30days, the nutrient composite soil had higher level of nutrient content.Superabsorbent polymer was added to the nutrient composite soil to conserve water and soil. The effect superabsorbent polymer on physical characteristics of the nutrient composite soil was studied. The results show that when the addition of superabsorbent polymer was0.5%-1%, the physical characteristics of the nutrient composite soil can be increased. With0.5%superabsorbent polymer addition, the physical characteristics of the nutrient composite soil were that water content was26.66%, bulk density was0.39g/cm3, specific gravity was2.17g/cm3, porosity was81.83%. And with1%superabsorbent polymer addition, the physical characteristics of the nutrient composite soil were that water content was29.27%, bulk density was0.37g/cm3, specific gravity was1.93g/cm3, and porosity was80.42%.