兽用抗生素磺胺二甲嘧啶对麦田NH3挥发的影响

为了研究磺胺类兽药抗生素对麦田NH₃挥发的影响，采用了田间原位观测试验，对比分析了不同浓度磺胺二甲嘧啶（SMZ）在不同氮肥类型条件下对麦田NH₃挥发的影响.试验共设9个处理，分别为：无氮肥无抗生素（CK）；复合肥为基肥，分别加施0，5，15，30mg/kg土的磺胺二甲嘧啶处理（CF、CF+SMZ5、CF+SMZ15、CF+SMZ30）；猪粪为基肥，分别加施0，5，15，30mg/kg土的磺胺二甲嘧啶处理（CM、CM+SMZ5、CM+SMZ15、CM+SMZ30）.所有施肥处理追肥均为尿素.结果表明：基肥阶段各处理之间的NH₃挥发速率无显著差异（P > 0.05），追肥阶段各处理之间有极显著差异（P<0.01），中高浓度SMZ表现为明显的促进作用（P<0.05）.整个观测期，CF、CF+SMZ5、CF+SMZ15、CF+SMZ30和CM、CM+SMZ5、CM+SMZ15、CM+SMZ30处理的NH₃-N损失百分比分别为5.5%、6.6%、13.9%、10.7%、11.0%、12.4%、11.9%、16.9%，其中CF+SMZ15、CF+SMZ30和CM+SMZ30处理显著增加了NH₃-N挥发累积量（P<0.05），其导致的NH₃-N损失比分别是同种基肥零抗生素添加的2.5、2.0和1.5倍，表明磺胺二甲嘧啶与复合肥的混施对土壤NH₃挥发的促进效应要高于与猪粪的同步混施.兽药抗生素对土壤NH₃挥发的影响不容忽视.因此，需大力加强对兽药抗生素的管控，并进一步探明不同兽药抗生素对土壤NH₃挥发的影响机制，为减缓兽用抗生素的环境污染生态效应作支撑.

Effect of veterinary antibiotics on NH3volatilization from winter-wheat field

To study the effect of veterinary antibiotics sulfamethazine (SMZ) in low, medium and high concentrations and their interactions with different N fertilizers on NH₃ volatilization from cropland, an in-situ observation experiment was conducted during the 2016~17 winter-wheat season. The treatments included no fertilizer and no antibiotics applied (CK), compound fertilizer used as basal fertilizer, with the addition of 0, 5, 15, 30mg/kg SMZ respectively (CF, CF+SMZ5, CF+SMZ15, CF+SMZ30), pig manure used as basal fertilizer, with the addition of 0, 5, 15, 30mg/kg SMZ respectively (CM, CM+SMZ5, CM+SMZ15, CM+SMZ30). Urea was applied as topdressing in all fertilizing treatments. The results showed that the NH₃ volatilization rate had no significant difference among all treatments during the basal fertilizing period (P > 0.05), while it had an extremely significant difference among all treatments during the topdressing period (P<0.01). SMZ in medium and high concentrations obviously increased the NH₃volatilization rate. During the entire sampling period, the percentage of applied N lost as NH₃-N for CF+SMZ5, CF+SMZ15, CF+SMZ30, CM+SMZ5, CM+SMZ15 and CM+SMZ30 treatments was 5.5%, 6.6%, 13.9%, 10.7%, 11.0%, 12.4%, 11.9% and 16.9%, respectively. In comparison with the same basal fertilizer and no SMZ use treatment, CF+SMZ15, CF+SMZ30 and CM+SMZ30 treatments significantly increased cumulative NH₃ volatilization (P<0.05) and they had 2.5, 2.0 and 1.5times as many percentages of NH₃ volatilization as CF or CM treatment, respectively. This indicated that the promoting effect of NH₃volatilization caused by SMZ mixed with compound fertilizer was much greater than that together with pig manure. Therefore, the effect of veterinary antibiotic on NH₃ volatilization in soils cannot be ignored. In order to reduce the environmental pollution of veterinary antibiotics, we should strengthen the management of veterinary antibiotics and need to further explore the mechanism of different veterinary antibiotics affecting soil NH₃volatilization in the future.