碳氮比对鸡粪堆肥中土霉素降解和堆肥参数的影响

Influence of C/N Ratio on Degradation of Oxytetracycline and Composting Parameters During Chicken Manure Composting

【目的】分析不同C/N处理下土霉素在鸡粪堆肥中的降解及其对堆肥理化性质的影响,以期阐明不同C/N处理对土霉素降解及堆肥腐熟度的影响。【方法】以鸡粪和小麦秸秆为原料,采用室内好氧堆肥法,研究鸡粪好氧堆肥过程中,不同C/N处理(T1:C/N=21.6、T2:C/N=25.5和T3:C/N=32.8)对鸡粪堆肥中土霉素的降解及堆体温度、pH、发芽指数等指标的影响。【结果】(1)C/N对鸡粪堆肥过程中土霉素的降解影响显著。整个堆肥期内,不同处理土霉素的降解速率大小顺序为T2>T3>T1。土霉素在各处理堆体中的降解均符合一级动力学方程,其相关系数介于0.9431—0.9967。(2)土霉素存在条件下,堆肥初始C/N对堆体温度是有影响的。C/N高的处理较C/N低的处理堆体温度上升速率快,达到最高温所需的时间也较短,最高温也较高。(3)C/N对土霉素存在下鸡粪堆肥堆体可溶性氮含量影响显著。如堆肥结束时T1、T2和T3处理堆体NO3--N与堆肥初始相比分别升高78.50%、62.37%和59.34%。(4)高C/N处理在一定程度上可以显著降低堆肥浸提液的生物毒性。如堆肥结束时C/N为25.5和32.8的处理GI>80%。【结论】对含有土霉素的鸡粪进行堆肥,较高的初始C/N(25.5-32.8)能够有效地促进鸡粪中土霉素的降解和鸡粪的腐熟。

[Objective] The effects of C/N on the OTC degradation and the physicochemical characters and maturity of chicken composts during chicken feces composting were studied. [Method] The indoor aerobic composting method was used in the present paper. Three groups of composting materials with C/N ratios of 21.6, 25.5 and 32.8 were prepared through combinations of chicken manure and wheat straw. To illustrate the effects of C/N on OTC degradation and composting process, OTC contents of chicken feces and the selected parameters such as pile temperature, pH, EC, contents of NO3-N, and NH4＋-N, and germination index（GI） in composting process were investigated. [Result] It was found that C/N has significant effects on the degradation of OTC, and the order of OTC degradation was T2〉T3〉T1. The degradation of OTC in chicken feces during composting could be well described by the first-order kinetic model, and the correlation coefficients ranged from 0.9431 to 0.9967. The effects were found of C/N on pile temperature during composting. The high C/N treatments had higher speed of temperature rising and the shorter time for temperature rising than the low C/N treatment. The highest pile temperatures were significantly higher than that of the low C/N treatment. Effects were also found of C/N on the soluble nitrogen contents of piles during composting. For example, the content of NO3-N of three treatments were increased by 78.50%, 62.37%, and 5934% at the end of composting, compared with their values at the beginning of composting. High C/N treatment could significantly reduce the biotoxicity of compost. For example, the treatmentswith C/N ratios of 25.5 and 32.8 had high GI values （The GI values are much higher than 80%）. [Conclusion] The highly initial C/N ranging from 25.5-32.8 could significantly decrease the OTC in chicken feces and be benefit for the chicken feces maturity.