| Straw returning as the main way of utilization of straw resources.With the strengthen of increasing soil nutrients and improving soil quality,it also brings many problems such as low germination rate,pests and diseases after straw returning,especially in northern spring corn,low temperature and drought.Limiting the effective decomposition of corn stalks,severely affects the second year of cultivation,sowing and emergence.The straw degradation is actually the process of microbial enzymolysis,constructing straw efficiently to degrade microbial flora is one of the effective ways to promote decomposition and improve the utilization of straw biological resources effectively.In this experiment,the corn straw that has been selected by the laboratory has been used to efficiently decompose the composite strain GF-20 at low temperature and obtain a better straw degradation effect.Based on the low-temperature stability,the GF-20 subculture strain was used to optimize its culture conditions,and a bacterial agent was applied to the field to provide a theoretical basis for microbial inoculation of corn stalks.The main findings are as follows.1.Microbial consortium GF-20 nitrogen source domestication:The composite strain GF-20 was subsequent to different ammonium sulfate and urea ratio culture conditions,obtaining different ratios of nitrogen source compound strains T,especially complex T2strains(Ammonium Sulfate+Urea=0.16%+0.04%)filter paper crash best.Cellulase activity and corn straw degradation rate are significantly higher than other treatments,the filter paper enzyme activity is 8.83-4.62U/ml and endonuclease activity was in the range of 14.61-4.63 U/ml.The degradation rates of corn stalks after 15 and 30 days of culture were 22.64%and 37.58%,respectively.2.Optimization of culture conditions for microbial consortium GF-20:Through orthogonal tests effects of different levels of glucose,nitrogen,calcium carbonate,and dipotassium phosphate on the filter paper cellulase activity of domesticated microbial bacteria GF-20.Through intuitive and analysis of variance,the results showed that the primary and secondary factors affecting cellulase activity were nitrogen source,carbon source,calcium carbonate,dipotassium hydrogen phosphate,When the concentration of glucose concentration of 0.5%,nitrogen concentration of 0.20%,and calcium carbonate concentration of 0.20%,dipotassium hydrogen phosphate was 0.05%,the cellulase activity was the highest.3.Effect of application microbial consortium GF-20:Study on application effect of microbial consortium GF-20 by indoor pot and field experiments,indoor pot experiment results show the application of the composite inoculant GF-20 significantly increased root surface area,root dry weight,root volume,root length and corn straw degradation rate,which increased by 4.97cm~2,0.021g,0.192cm~3,72.66cm,and 7.63%,respectively.The results of the field experiment showed that the nutrient content in the soil treated with straw degrading bacteria had a different degree of improvement than that in the control soil,and soil nutrients were first increased and then decreased in different periods.The highest nutrient content in soils treated with microbial consortium GF-20 was the highest in each treatment,and soil alkali hydrolyzable nitrogen,soil available potassium,soil available phosphorus,and soil organic matter increased by 22.05mg/kg,85.54mg/kg,7.75 mg/kg,8.44 g/kg,respectively compared to the non-application of straw and all reached significant levels. |
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