土霉素广泛存在于土壤和水体中，可能对农业生态环境构成潜在威胁。含土霉素的粪便作为有机肥施用是土霉素进入土壤和水体的主要途径之一。因此，实现粪便堆肥过程中土霉素的有效去除，并明确土霉素存在下堆肥有机质的转化规律十分重要。本文通过调节不同初始含水率（45%、55%、65%），外源模拟添加土霉素，将鸡粪和小麦秸秆共堆肥，以研究堆肥过程中土霉素降解及有机质变化规律。研究结果表明，堆肥初始含水率对土霉素降解有显著影响，与较低初始含水率相比，初始含水率为65%更有利于土霉素降解（降解率77.4%）和堆肥腐熟，然而，高初始含水率（65%）可能促进堆肥过程的硝化作用，从而增加了氨挥发。此外，增加堆肥初始含水率可以提高堆肥温度。核磁共振结果显示，土霉素的存在可以影响脂肪类物质的内部转化，从而抑制堆肥的腐殖化。55-65%的初始含水率可以缓解粪便堆肥过程中土霉素对腐殖化的影响。

A solution culture experiment was performed to investigate the effects of oxytetracycline (OTC) on wheat (Triticum aestivum L.) growth, chlorophyll contents, and photosynthesis at five levels of 0, 10, 20, 40, and 80 mmol L-1 OTC. OTC is toxic to wheat. The wheat growth, especially wheat root was significantly decreased. Further OTC also significantly decreased root activity, chlorophyll contents, and photosynthetic parameters except for intercellular CO2 concentrations. The different responses of indicators such as root number, root activity and so on to OTC were also observed. The IC50 values for the tested indicators to OTC ranged from 7.1 to 113.4 mmol L-1 OTC. The order of indicator sensitivity to OTC was root number > stomatal conductance > chlorophyll a > total chlorophyll > photosynthetic rates > total surface area > transpiration rate > chlorophyll b > fresh weight of root > dry weight of root > total length > dry weight of shoot = fresh weight of shoot > total volume. The root number was more sensitive than other indicators with the IC50 value of 7.1 mmol L-1 OTC, and could be taken as the sensitive indicator to predict the hazards of OTC to wheat.