Abstract:

The ecological risk caused by the accumulation of antibiotics in farmland soil has become the focus of research globally. Studying the nutrient cycle of the farmland soil ecosystem under the influence of antibiotics by the change of soil enzyme activity has great ecological importance. In this study, three farmland soils with different pH values, acid soil, neutral soil and alkaline soil, were studied. They were treated with three antibiotics: Oxytetracycline (OTC), Enrofloxacin (ENR) and Sulfamethazine (SM2), respectively, which were widely used in the livestock and poultry breeding industry. We analyzed the sensitivity of urease, catalase and phosphatase to antibiotics in the three soils. The results showed that during the 0-28 days, urease activity showed an overall inhibitory trend; catalase activity showed an increasing trend in general; and phosphatase activity varied with the addition of different antibiotics. At the 28th day, compared with the control group, urease activity was significantly inhibited in the acidic and neutral soils added with three antibiotics and in the alkaline soil added with ENR and SM2, and the inhibition rate was 38.03%-96.08%. But urease activity was promoted in alkaline soil with OTC, and the promotion rate was 28.43%. Catalase activity was significantly promoted in acidic soils supplemented with three antibiotics and neutral and alkaline soil with OTC and SM2, and the promotion rate was 24.88%-268.25%. However, catalase activity was inhibited in neutral and alkaline soil with ENR, with the inhibitory rates of 18.42% and 29.04%, respectively. Phosphatase activity was significantly stimulated at 14.73%-101.26% in the three soils with OTC, and had no significant change in the three soils with ENR. But phosphatase activity was significantly depressed at 61.83%-70.54% in the three soils with SM2. The study showed that antibiotics had complex effects on soil enzyme activity, especially the inhibition of urease activity, which weakened the metabolic function and stability of enzymes related to the soil nitrogen cycle, thereby affecting the functional stability of the soil ecosystem.

Key words: oxytetracycline, enrofloxacin, sulfamethazine, farmland soil, soil enzyme activity

摘要：

农田土壤抗生素累积产生的生态风险已成为目前国内外研究的热点，土壤酶活性的变化对于研究抗生素影响下的农田土壤生态系统养分循环，具有重要的生态学意义。分别以酸性、中性和碱性农田土壤为研究对象，添加畜禽养殖业中常用的3种抗生素--土霉素（Oxytetracycline，OTC）、恩诺沙星（Enrofloxacin，ENR）和磺胺二甲嘧啶（Sulfamethazine，SM2）进行处理，分析了土壤中脲酶、过氧化氢酶和磷酸酶对抗生素的敏感性。结果表明，在添加抗生素处理的0-28 d过程中，脲酶活性整体呈现抑制趋势，过氧化氢酶活性整体呈现促进趋势，磷酸酶活性随着添加抗生素的不同呈现不同的变化趋势。在28 d时，与对照组相比，脲酶活性在添加3种抗生素的酸性、中性土壤中及添加ENR与SM2的碱性土壤中均显著受到抑制，抑制率为38.03%-96.08%，而在添加OTC的碱性土壤中受到促进，促进率为28.43%；过氧化氢酶活性在添加3种抗生素的酸性土壤中及添加OTC与SM2的中性、碱性土壤中均受到促进，促进率为24.88%-268.25%，而在添加ENR的中性、碱性土壤中受到抑制，抑制率为18.42%和29.04%；磷酸酶活性在添加OTC的3种土壤中均受到促进，促进率为14.73%-101.26%，而在添加ENR的3种土壤中均无显著变化，在添加SM2的3种土壤中均受到抑制，抑制率为61.83%-70.54%。该研究表明抗生素对土壤酶活性影响复杂，尤其是对脲酶活性的抑制，减弱了土壤氮循环相关酶的代谢功能及其稳定性，进而影响土壤生态系统的功能稳定性。

关键词: 土霉素, 恩诺沙星, 磺胺二甲嘧啶, 农田土壤, 土壤酶活