腐熟堆肥回流对中药渣好氧堆肥进程及堆肥品质的影响

Matured compost recycling enhances the efficiency of composting and improves the quality of end-products during composting of herb residues

为明确腐熟堆肥回用对中药渣好氧堆肥腐熟效率及堆肥产品品质的影响,探讨堆肥过程中养分转化规律及腐殖质形态、组分、品质的动态变化,在工厂化条件下比较了中药渣自然堆肥与添加腐熟中药渣堆肥(质量分数10%)堆肥过程中碳氮磷硫和腐植酸类物质的动态变化特征。结果表明,添加腐熟堆肥比自然堆肥提前20 d进入高温期,且高温期平均温度高于自然堆肥5℃左右。较之自然堆肥,添加腐熟堆肥可以强化有机物降解,堆肥产品的总碳含量与C/N显著下降(P<0.05),而全氮、全磷、全钾和全硫分别增加17.5%、17.8%、14.7%和9.4%;两个处理堆肥前后总腐植酸、游离腐植酸和水溶性腐植酸含量变化不大,但添加腐熟堆肥处理可提高腐植酸的活性,增加游离腐植酸(7.8%)及水溶性腐植酸含量(30.1%);堆肥过程胡敏酸组分不断增加,富里酸组分逐渐降低,添加腐熟堆肥处理可强化堆肥腐殖化进程,增加胡敏酸组分(15.2%),胡富比显著升高,堆肥产品的分子量、缩合度及芳构化程度提高。研究表明,腐熟堆肥回流能够显著促进中药渣堆肥腐熟效率,提高堆肥产品品质。

Matured compost recycling is widely practiced to reduce the dosage of organic bulking agents used in actual composting processes and is therefore economically advantageous. In order to ascertain the effect of matured herb residue compost backflow on maturation efficiency of composting and quality of compost, this study discussed the transformation of nutrients as well as humus(composition, content,and quality)during the composting process. Two treatments were conducted to achieve this objective. The matured herb residue compost was used in composting in the proportion of 10% of initial raw materials(based on dry weight). A control treatment(CK)was also studied without application in industrial condition. During the experiment, the content of total carbon(TC), total humus(HS), free humus(FHS),water-soluble humus(WSHS), humic acid(HA), fulvic acid(FA), and some elements such as C, N, P, and S were determined. Results showed that matured compost amendment(MCT), wherein the thermophilic phase(55 ℃)was entered 20 days earlier than that in CK,could significantly accelerate the degradation of organic matter. When compared with CK, application of matured compost resulted in significant reduction in final TOC and C/N ratio(P<0.05), whereas, total N, total P, total K, and total S increased by 17.5%, 17.8%, 14.7%, and9.4%, respectively. Moreover, MCT dramatically improved the activity of humus, as indicated by the increase in the content of HS, FHS,and WSHS in compost products. During the composting process, HA content increased and FA content decreased, resulting in increased HA/FA ratio, especially in the treatment with matured compost, indicating that MCT accelerated organic matter humification and improved the humus quality. Our results suggest that matured compost recycling could magnify the nutrient and humus quality during composting of agricultural organic wastes.