| Straw returning to field is a effective way to improve the straw use efficiency, improve fertility and micro-environment of soil. But the course of maize straw decompose is very slowl, returning maize straw directly to soil will affect the quality of tillage and sowingl, and cause the waste of resource. The research take the high-efficiency corn straw degradation composite microbial system extracted from saw powder as trial material, study the growth and enzyme production characteristics, the optimization of fermentation conditions and straw degradation ability in liquid state. Then produce bio-microbial inoculum and use in the field to provide the oretical basis and technical support for the maize straw degradation in the north low-temperature area. The result is as follows:1. Through measure growth curve, pH value, the degradation rate of straw and dynamic changes of lignocellulose For GF-S3 and GF-S72, we get the result that 15d straw degradation rate of GF-S3 and GF-S72 is 23.50%,25.50% respectively. Residual quantity of cellulose, hemicellulose, and lignin descend from former 2.56 g,1.37 g and 0.42 g to 1.27,1.17; 0.70,0.65; 0.24,0.23.2. Measure cellulose enzyme activity and maize straw degradation rate, then carry out the orthogonal experiment to research the fermentation conditions of low-temperature and high-efficiency degradation composite strains and optimize it. Best shake flask culture conditions of compound strains GF-S72 is:quantity of 2%, initial pH8, cultivation temperature 10℃, cultivation time 6 d, fluid volume 18 ml, nitrogen source urea nitrogen, nitrogen source concentration 0.1%, mixed ratio 2:1, carbon and nitrogen rate 20:1.3. Study of pharmaceutical formulation for low-temperature and high-efficiency degradation composite strains shows that:the best supports:diatomaceous soil, the rate of bacterial fluid and support is 3:1, the best rate of bacterial fluid and maize straw is 0.05g:2g, the value of PH for GS-72 is 8.2, water moisture is 1.42%, the activity of cellulose enzyme is 0.879 U·mL-1; OD is 0.302; the preservation moisture is 10%, the preservation temperature is 15℃ and quality storage period of the bacterial fluid can last three months under the above conditions.4. The test of the function of low-temperature and high-efficiency degradation maize straw composite strains through the degradation rate of the maize straw and a variety of enzyme activity index shows that:Maize straw degradation rate:indoor soil culture:The maize straw degradation rate of low temperature high efficient degradation compound inoculants GF-S72:15℃>10℃. Outdoor soil culture:the maize straw degradation rate is GF-S72 GF-S72>LK>CK. Field experiment:the maize straw degradation rate is LK>GF-S72>CK.Soil enzyme activity:Indoor soil culture:the cellulose enzyme activity under the condition of 14d 10℃ and 15℃ are 1.14 mg/g and 1.42 mg/g separately. The highest content of phosphatase and urease under the condition of 28d and 10℃ are 51.73 and 3.42mg/g separately, and 58.23 and 4.10 mg/g under the condition of 28d and 15℃. The outside soil culture:cellulose enzyme activity of GF-S72 and LK under the condition of 14 d are 1.30 and 1.20 mg/g separately. The highest contain of GF-S72 Phosphatase and urease under the condition of 28 d GF-S72 are 47.29 and 3.40 mg/g separately, while LK are 45.05 and 3.22 mg/g. Field experiment:cellulose enzyme activity of GF-S72 and LK under the condition of 14 d are 1.28 and 1.42 mg/g separately. The contain of highest phosphatase and urease of GF-S72 under the condition of 28 d are 51.90 and 3.49 mg/g saparately. While LK are 57.30 and 57.30 mg/g separately. |
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