添加腐熟猪粪对猪粪好氧堆肥效果的影响

摘要

为明确添加腐熟猪粪对猪粪好氧堆肥启动期和高温期微生物数量及酶活性变化规律，探讨微生物影响堆肥温度的机制，揭示影响畜禽粪便堆肥持续高温的主要微生物，该研究比较了猪粪自然堆肥与添加腐熟猪粪(质量分数3%)堆肥过程中有机质降解及嗜温、嗜热微生物数量和脱氢酶、蛋白酶、纤维素酶活性变化特征。结果表明，24 h内添加腐熟猪粪堆肥温度比自然堆肥高出5℃，但高温期平均温度较自然堆肥低8℃，高温（＞50℃）期比自然堆肥短4 d。自然堆肥和添加腐熟猪粪堆肥嗜温菌数量先高后低，嗜热菌数量随着温度的升高而上升。添加腐熟猪粪堆肥升温期嗜温、嗜热细菌和纤维素降解菌增殖速度较快，且数量分别比自然堆肥高出12.2%、152.6%、60.3%。添加腐熟猪粪堆肥脱氢酶、纤维素酶活性高峰提前，并使蛋白酶活性增加4.9%。但高温期后，嗜热纤维素降解菌数量比自然堆肥少22.5%，纤维素酶活性及有机质损失率也分别比对照低25.8%、6.1%。以上结果表明，在猪粪高温好氧堆肥中添加腐熟猪粪可以加快堆肥初期升温速度，但由于高温期嗜热纤维素降解菌数量减少，纤维素酶活性降低，不能促进猪粪堆肥持续高温。该研究为猪粪堆肥菌剂的筛选及适宜的接种时间提供依据。%Microbial inoculation is often performed to accelerate the process of composting and improve the quality of the compost, but its effect is controversial. The effectiveness of inoculants in composting mainly depends on the properties of the raw material and microorganisms applied. It is therefore important to propose a strategy of inoculation based on the evolution of biochemical and microbiological characteristics at different composting stages. In this study, two composting piles with pig manure (CK) and pig manure inoculated with 3% (w/w) matured compost (T) were composted for a total of 11 days. Various biochemical and microbiological parameters were analyzed during the process of composting. The experimental results indicated that windrow temperature in the inoculated pile was 5℃ higher than CK at 24 h of composting (P<0.05). The inoculated pile reached peak temperature six hours earlier than non-inoculated. However, the average temperature of the inoculated pile was 8℃ lower than CK in the thermophilic stage of composting, and the maintenance of high temperature (>50℃) in inoculated pile was four days shorter. The degradation of organic matter, as indicated by the reduction of C/N ratio and the organic matter loss rate, was higher in the inoculated pile in the early composting stage. The dynamic of microbial evolution was similar between the inoculated and non-inoculated. The number of mesophilic microorganisms increased in the initiation phase but decreased in the thermophilic phase of composting, while the number of thermophilic microorganisms in the two piles increased with the increase of the temperature. Inoculation of pig manure compost increased the multiplication rates of mesophilic bacteria, thermophilic bacteria and cellulose degradation microorganisms in the initiation phase. Compared with CK, the numbers for mesophilic bacteria, thermophilic bacteria and cellulose degradation microorganisms in the inoculated pile were increased by 12.2%, 152.6%, 60.3%, respectively. The peak values of dehydrogenase activity and cellulase activity were brought forward and the protease activity was enhanced by 4.9% in the inoculated pile. However, the populations of thermophilic cellulytic bacteria was 22.5% lower and the cellulose activity as well as the degradation of organic matter was 25.8% and 6.1% lower in the inoculated pile than the control in the thermophilic phase. Above all, compost inoculation was able to accelerate the initiation rate at the early stage of pig manure compost, however, inoculated was neither effective to prolong the thermophilc stage nor increase the peak temperature during composting, because of the decreased number of cellulytic microorganism and cellulose activity in the thermophilic stage. As a result, we proposed that inoculation of thermophilic cellulose decomposition microorganism at the thermophilic stage of the process would be necessary in order to facilitate decomposition of pig manure.