葡萄枝堆肥腐殖化的微生物养分限制机理探讨

Exploring the microbial nutrient limitation mechanisms of grape branch compost humification

胞外酶活性及其化学计量变化可以反映微生物的养分限制类型,调理剂添加或超高温预处理可促进好氧堆肥腐殖化效果,为研究其对葡萄枝堆肥养分限制及其调节机制,本研究以葡萄枝+鸡粪(CK)为基本堆肥原料,另设置添加15%(m/m)菇渣组(M)和进行高温预处理组(H)两个处理,在60 L强制曝气好氧发酵罐中进行45 d的堆肥化试验,测定不同阶段堆肥理化指标及参与C、N、P转化的功能酶活性和化学计量比,旨在从微生物养分限制的角度探讨这两种措施对葡萄枝高温堆肥腐殖化的影响机理。结果表明:添加菇渣和高温预处理改变了堆肥基质的特性,加速有机质降解,提升养分含量,并促进了腐殖化。CK、M、H的高温期(>50℃)分别保持了19、15、19 d,均能满足种子发芽指数≥70%,pH值在5.5~8.5之间等腐熟标准指标。堆肥结束时,M和H相比CK分别提升了9.81%、12.44%的TN含量和9.84%、9.04%的TP含量。M和H使堆肥中胡敏酸碳含量在第14~44天分别较CK提升7.64%~37.62%和9.26%~36.96%;第0~7天,M的碱性磷酸酶(AP)、β-1,4-葡萄糖苷酶(BG)、β-1,4-N-乙酰氨基葡萄糖苷酶(NAG)的酶活性显著高于CK(P<0.05),第14~21天,H的AP、BG、NAG的酶活性显著高于其他两组(P<0.05)。M和H中的微生物受到N和P养分的限制,结构方程模型显示,这两个处理的微生物群落会分泌较多的N和P获取酶来对有机氮和有机磷进行矿化以应对养分限制,提升TN、TP的含量,促进胡敏酸的生成。研究表明,在葡萄枝鸡粪堆肥中添加菇渣以及使用高温预处理可以增强胞外酶活性、提升养分含量,促进胡敏酸的形成。

This study aims to explore the mechanism of influence of these measures on the humification of grape branch compost from the perspective of microbial nutrient limitation.Extracellular enzyme activity and its stoichiometric changes can reflect the type of nutrient limitation of microorganisms.Conditioner addition or hyperthermophilic temperature pre-treatment can promote an aerobic compost humification effect.In order to study the nutrient limitation of grape branch composting and its regulation mechanisms,this study used grape branch and chicken manure(CK)as raw material for compost,added 15%(m/m)mushroom substrate(M)and hyperthermophilic pre-treatment(H)and performed a composting experiment for 45 days in a 60 L forced aerobic fermentation tank.Physicochemical indicators,functional enzyme activities,and stoichiometric ratios involved in C,N,and P conversion in compost at different stages were all determined.The results showed that the addition of mushroom residue and hyperthermophilic pre-treatment changed the characteristics of the compost substrate,accelerated organic matter degradation,enhanced nutrient content,and promoted humification.CK,M and H were maintained for 19,15,and 19 days,respectively,during the high temperature period(>50℃).All three met the decomposition standards,namely seed germination index≥70%and pH value between 5.5 and 8.5,etc.At the end of composting,M and H enhanced the total nitrogen(TN)and total phosphorus(TP)contents by 9.81%,12.44%,and 9.84%,9.04%,respectively,compared with CK.M and H elevated the humic acid content of the compost by 7.64%-37.62%and 9.26%-36.96%on days 14–44,respectively,compared to CK.On days 0-7,the alkaline phosphatase(AP),β-1,4-glucurosidase(BG),andβ-1,4-N-acetylglucosidase(NAG)activities of M were significantly higher than that of CK(P<0.05),and on days 14-21,the AP,BG,and NAG enzyme activities of H were significantly higher than those of the other two groups(P<0.05);Microorganisms in M and H were limited by N and P nutrients.The structural equation model showed that the microbial communities secreted more N and P acquisition enzymes to mineralize organic nitrogen and organophosphorus to cope with nutrient restrictions,increased the content of TN and TP,and promoted the production of humic acid.The addition of mushroom residue and the use of hyperthermophilic pre-treatment in the compost of grape branch-chicken manure can enhance extracellular enzyme activity,increase nutrient content,and promote the formation of humic acid.