利用响应曲面法优化秸秆腐熟剂的腐解条件

以水稻秸秆为代表,研究了4种腐熟剂对秸秆腐解性能的影响。基于施用腐熟剂后的秸秆腐解率和碳氮比,选择其中1种腐解性能较好的腐熟剂,采用Box-Behnken设计对其秸秆腐解条件进行优化,主要考查腐熟剂用量、温度、含水量和外加氮源(浓缩沼液)量等4个因素。结果表明,腐解温度、含水量和腐熟剂用量对腐解率的影响达到极显著水平(P<0.01),最佳腐解条件是温度29.6 ℃,含水量90%,腐熟剂和浓缩沼液氮添加量分别为秸秆质量的2.0%和0.17%。数学模型分析预测得知,在该条件下腐熟剂添加后25 d水稻秸秆腐解率可达63.25%,与验证试验结果基本相符。

Optimization of straw decomposition with inoculants by using response surface method

The rice straw was selected as typical straw to illustrate the influence of 4 straw-decomposing inoculants on the decomposition of straws. Based on the decomposition rate and ratio of carbon to nitrogen of rice straw, one inoculant with better straw decomposing capacity was selected for optimization of straw decomposing conditions by Box-Behnken design. The result demonstrated that among the four factors, namely, straw-decomposing inoculant content, temperature, water content and extra-nitrogen (biogas slurry) content, the effect of temperature, water content and straw-decomposing inoculant content on decomposition rate reached the significant level of P<0.01. The predicted optimum conditions for straw decomposing were temperature of 29.6 ℃, water contents of 90%, straw-decomposing inoculant content of 2.0% of the straw weight, and extra-nitrogen content of 0.17% of straw weight. According to the mathematical model, the maximum decomposition rate on 25th day was 63.25%, and it was consistent with the decomposition rate revealed by verification experiment under the above conditions.