Study On The Utilization Of Different Organic Wastes As Fertilizer

1. A culture experiment was conducted to study the effects of organic materials (such as cow muck, chicken manure, pig manure, and sludge) on soil nutrient and enzyme activity. The results showed that the experimental materials all significantly increased the contents of soil nutrients. Cow dung had the highest effect to increase soil organic matter, and chicken manure and pig manure both increased soil total nitrogen, alkali solution nitrogen, and rapidly-available potassium. The effect of sludge was inferior to livestock and poultry dung. Organic materials significantly increased the activities of soil urease, phosphatase, and protease, but the effect on the activities of catalase and sucrase was not significant. The cow dung had better effect to improve soil invertase activity and sludge had better effect to improve soil phosphatase activity.2. By analizing and comparing the contents of nutrient substances and heavy metals in different biogas fertilizers from gaoping city of Shanxi Province and based on the relevant quality standards and evaluation methods, the agricultural security of biogas fertilizer was evaluated. Organic-inorganic mixed fertilizer was made by biogas fertilizer with inorganic fertilizer and a pot experiment planted with Pak-choi was conducted to compare the effects of the organic-inorganic mixed fertilizer, inorganic fertilizer, pure biogas, and commercial organic feitilizer on the growth, yield, quality, and fertilizer utilization efficiency of Pak-choi and the enzyme activity and nutrients of soil. Finally a best organic-inorganic mixed fertilizer was selected. The following conclusions were obtained:(1)The pH values of biogas fertilizers were all alkalinity. The contents of total N and total P were higher in biogas slurry of chicken manure, the contents of organic matter and total K were higher in biogas slurry of straw. The contents of total N, total P, available N, and available P were higher in biogas residue of pig manure than in biogas residue of straw. But the contents of organic matter, total K, and available K were higher in biogas residue of straw than in biogas residue of pig manure. The ratio of available P to total P was the highest in the two kinds of biogas residue. The Cl concentration was the highest among the medium and trace elements and exceeded the farmland irrigation water quality standards (GB5084-2005), then followed by Ca and Mg, and Cu content was lowest in the three kinds of biogas slurry. The contents of Ca and Fe were higher among the medium and trace elements in the 6 biogas residues and the contents of Mn and Cu were lower in the 3 biogas residues of straw. The As content exceed organic fertilizers standards (NY525-2012) in the pig manure biogas residue of No.1.(2) Comparing with inorganic fertilizer treatment, the contents of soil organic matter, total nitrogen, and available phosphorus in the treatments of organic-inorganic mixed fertilizers made by different biogas resdues increased 12.4%-26.3%,0.1%-10.3%, and 10.1%-30.1%respectively. The effects of organic-inorganic mixed fertilizers made by straw biogas residue were better than that by pig manure biogas residue. The commercial organic fertilizers significantly increased the activity of soil catalase and the organic-inorganic mixed fertilizers made by biogas residues were better for increasing the activity of soil urease.(3) Different fertilization treatments promoted the growth of pak-choi and the yields of pak-choi increased by 20.9%-69% compared to CK. The yields of pak-choi were highest in the treatments of organic-inorganic fertilizers blended by pig manure biogas residue and were 352.28 g·pot-1 and 349.33 g·pot-1 respectively, and followed by the treatments of organic-inorganic fertilizers blended by straw biogas residue.(4) Comparing to inorganic fertilizer treatment, the treatments of organic-inorganic fertilizers blended by biogas residues reduced the nitrate contents of pak-choi by 8.5%-131%, increased the water soluble ssugar contents by 13.1%-23.6%, and increased the reduced Vc contents by 18%-38.2%.(5) Comparing to CK, different fertilization treatments imcreased the absorption of Pak-choi plants to NPK nutrients, comparing to inorganic fertilizer treatment Ⅱ, the effect of organic-inorganic fertilizers blended by pig manure biogas residue ④ to improve NPK nutrients utilization Pak-choi was the best, and increased by 79.6%,72.4% and 58.0%, respectively, followed by organic-inorganic fertilizers blended by pig manure biogas residue ③, and organic-inorganic fertilizers blended by straw biogas residue was poor.Comprehensive the effects of organic-inorganic fertilizers blended by biogas residue on Pak-choi growth and yield, soil nutrient and enzyme activity, and nutrient utilization rate, organic-inorganic fertilizers blended by pig manure biogas residue ④ was the best.