水稻秸秆预处理对猪粪高温堆肥过程的影响

Influence of straw pretreatment on the thermophilic composting process with pig manure

通过预处理技术打破秸秆中的木质纤维素复杂结构,能够有效加速秸秆的分解过程。为了探讨不同秸秆预处理方法对秸秆与畜禽粪便混合堆肥效率的影响,通过添加秸秆腐熟剂(B)和氢氧化钙(C)分别对水稻秸秆进行10 d(B1、C1)和20 d(B2,C2)的预处理静态堆置,以无预处理的秸秆为对照(CK),与猪粪按比例混合后进行好氧堆肥。运用红外光谱(IR)、扫描电镜(SEM)对预处理前后的水稻秸秆进行了分析,并通过比较不同处理堆肥过程中温度、p H、水溶性铵态氮/水溶性硝态氮(NH+4-N/NO-3-N)、电导率(EC)、T值[(C/N)终点/(C/N)起点]和种子发芽率(GI)的变化来研究不同预处理方法对堆肥腐熟过程的影响,通过对比堆肥产物总养分含量来进一步确定最优的秸秆预处理方式。结果显示,秸秆腐熟剂预处理能够有效破坏水稻秸秆细胞壁和复杂的纤维结构,使其内部组织暴露、出现大量的孔隙和微孔道。氢氧化钙预处理也能对水稻秸秆结构产生破坏,但其内部组织暴露较少,几乎没有微孔;秸秆腐熟剂对水稻秸秆进行预处理,其破坏性强于氢氧化钙处理,且处理时间越长效果越好。相比对照,秸秆腐熟剂处理后能够缩短堆肥高温期8~13 d。堆肥结束后,所有秸秆预处理的堆体p H均降至8.5以下;B1、B2、C2的NH+4-N/NO-3-N小于0.5,符合腐熟评价标准,但CK和C1未达到腐熟标准;除B2外各处理T值均低于0.6,所有处理的GI均在堆肥第28 d达到50%。秸秆预处理后的堆体总养分含量均高于CK(CK、B1、B2、C1、C2的总养分分别为11.09%、11.49%、13.29%、11.75%、11.37%),其中B2总养分含量显著高于其他处理。总体来看,秸秆预处理可以加快堆体的腐熟过程,提高堆肥产物质量,其中采用秸秆腐熟剂预处理20 d的效果最为明显。

Breaking up the complex structure of lignocelluloses in straw by using pretreatment technology is an effective method for accelerating straw decomposition.Thus,in the present study,rice straw was pretreated by a straw decomposing agent(B)and calcium hydroxide(C),for 10 days(B1,C1),and 20 days(B2,C2).Rice straw without pretreatment was set as the control(CK).The above straw was then mixed with pig manure for the thermophilic composting process.Infrared spectroscopy(IR)and scanning electron microscopy(SEM)showed that the cell wall and fiber structure of rice straw was destroyed by the straw decomposing agent,leading to the exposure of internal tissues,and generating micro-pores on the straw.However,lesser internal tissues were exposed,and fewer micro-pores were generated,on straw pretreated with calcium hydroxide.Overall,pretreatment with the straw decomposing agent for 20 days showed the most destructive effects on rice straw.Compared with the control,the period of high temperature can be shortened by 8~13 days after pretreatment with the straw decomposing agent.At the end of composting,the pH in all the pretreated compost was below 8.5;NH+4-N/NO-3-N of B1,B2,and C2 was less than 0.5 and met the requirements of the maturity evaluation standard.The T values[(C/N at the beginning of composting)/(C/N at the end of composting)]of B1,C1,and C2 were less than 0.6.Pretreated straw showed a higher total nutrient content than CK,and B2 showed a significantly higher total nutrient content than all the other treatments.In summary,straw pretreatment can accelerate the composting process and improve the quality of composting products.Pretreatment with the straw decomposing agent for 20 days showed the best results.