低温高效降解玉米秸秆复合菌系发酵条件优化及腐解菌剂的研究

为解决北方低温条件下玉米秸秆降解难的问题,利用筛选于锯末的一组玉米秸秆降解复合菌系GF-S72,通过单因素、正交试验及载体生物相容性试验,研究了复合菌系的发酵条件、菌剂载体类型、用量及保存条件。结果表明,复合菌系GF-S72最佳发酵条件为:尿素0.1%、碳氮比20∶1、培养温度10℃、初始p H为8.0、装液量18 m L/150 m L、培养时间6 d、接种量2%。基于试验选取硅藻作为最佳载体,在菌液∶载体=3∶1、菌剂与秸秆配比为0.05 g/2 g,制备低温高效降解玉米秸秆复合型菌剂。试验结果还表明,p H值为8.2、含水量为1.42%、保藏湿度为10%、保藏温度为15℃时,复合型菌剂降解玉米秸秆的效率最高。

Optimization of fermentation conditions for low-temperature and high-efficiency composite microbial system for corn stover degradation and preliminary development of microbial inocula

Straw-returning to fields is an effective way to increase soil organic matter content and soil fertility, stimulate soil microbial activ-ity, enhance crop yields and quality, and improve the soil physical and chemical properties. It, therefore, plays a crucial role in promoting a-gricultural sustainable development. In the spring corn region of northern China, however, maize stover degradation is often slow and is even not fully complete in the fall and winter seasons because of low temperature, which causes wasting of resources. Thus, it is necessary to de-velop efficient stover-decomposing bacterium agent for low-temperature conditions. A low-temperature and high-efficiency composite mi-crobial system, GF-S72, screened from sawdust and degraded corn stover, was developed for degrading corn stover. Result indicated that the best fermentation was urea of 0.1%, C/N ratio of 20﹕1, inoculating content of 2%, initial pH of culture medium at 8.0 and liquid medium vol-ume of 18 mL/150 mL at 10℃for 6 d. The experiment showed that diatomite was the best carrier, and high-efficient composite bacterium a-gent for degrading corn stover was prepared at low-temperature. The experiment also showed that the highest efficient microbial inoculants of corn stover degradation was at 3﹕1 of bacterial liquid/carrier, 0.05 g/2 g of microbial inoculants/corn stover ratio, 1.42%of moisture con-tent, 10%of preservation humidity, 15℃of preservation temperature, and pH 8.2.