含氯氮肥对太湖稻麦轮作体系氨挥发及作物产量的影响

摘要

[目的]通过研究尿素、氯化铵以及二者混合高塔造粒而成的含氯脲铵氮肥对太湖地区稻麦轮作体系作物产量、氮肥利用率、氨挥发损失、土壤氯残留和耕层土壤pH的影响,为新型含氯氮肥的推广,降低环境风险提供理论依据.[方法]通过两年稻麦轮作季的田间小区试验,在当地适宜施氮量条件下,以CK(不施氮)和施用普通尿素为对照,研究了两种含氯氮肥的施用对稻麦轮作体系作物产量和氮肥利用率的影响.采集作物收获后0-20 cm、20-40 cm土壤样品,采用硫氰酸汞比色法测定土壤氯残留;施肥后采用密闭室间歇通气-稀硫酸吸收法测定氨挥发通量.[结果]尿素、氯化铵和含氯脲铵处理对稻麦产量无显著影响,但与尿素相比含氯脲铵对稻麦有增产的趋势,而氯化铵对小麦有减产趋势.与尿素相比施用含氯脲铵显著提高氮肥利用率7.0％(P＜0.05).氨挥发主要发生在稻季,与施用尿素相比单施氯化铵使麦季氨挥发降低26.3％ (1.39 kg/hm2),而使稻季氨挥发增加10.4％ (2.67 kg/hm2);含氯脲铵使麦季和稻季的氨挥发分别降低5.2％ (0.55 kg/hm2)和12.9％ (6.16 kg/hm2).施用含氯氮肥土壤氯残留表现为稻季显著增加,而麦季则显著降低的趋势,收获期耕层土壤(0-20 cm)氯离子含量最高不超过160 mg/kg,低于水稻和小麦的耐氯临界值.经过两个稻麦轮作循环后,施用氯化铵土壤pH比尿素下降0.88个单位,而施含氯脲铵土壤pH与尿素没有显著差异.[结论]在太湖地区稻麦轮作体系中,综合考虑产量和环境效益,含氯脲铵氮肥与两种单质肥料相比有一定优势,为氨挥发减排和氯化铵施用难题的解决提供了依据.%[Objectives] With the aim of marketing a new technological chlorine-containing fertilizer with decreasing environmental risk,we gained insight into crop yield,nitrogen use efficiency (NUE),ammonia volatilization,soil residual chlorine and pH in soil from rice-wheat rotation system with addition of urea,ammonium chloride and urea-ammonium mixed nitrogen fertilizer (urea ∶ ammonium chloride =1 ∶ 1,manufactured with tower spray granulation technology,UAMF) in Taihu Lake region.[Methods] Taking the no fertilizer application (CK) and conventional urea application (U) as two controls,effect of the chlorinecontaining N fertilizer was studied through a two-rotation filed plot experiment in Taihu Lake region.The chlorine residual at the depths of 0-20 cm and 20-40 cm soil after the harvest was determined with the mercury thiocyanate spectrophotometry.The NH3 volatilization was measured by a dynamic chamber method.[Results] There were no significant differences in statistics among grain yields for the applied urea,ammonium chloride and UAMF.But compared with the urea fertilizer,the UAMF had a higher trend for the rice and wheat yields and the ammonium chloride had a lower trend for the wheat yield.In addition,the UAMF significantly increased the NUE by 7.0％ compared to the urea application (P ＜ 0.05).The NH3 volatilization occurred primarily during the rice season rather than during the wheat season.Compared to the NH3 volatilization from the urea,the NH3 volatilization amounts of the ammonium chloride were decreased by 26.3％ (1.39 kg/hm2) in wheat season but increased by 10.4％ (2.67 kg/hm2) in rice season.In contrast,the UAMF presented 5.2％ (0.55 kg/hm2) and 12.9％ (6.16 kg/hm2) decreases in wheat and rice season,respectively.The two chlorine-containing fertilizers both increased significantly the load of the chlorine residual in soil during the rice season but had a reduced trend during the wheat season.Above all,the chlorine residual in soil after the harvest was less than 160 mg/kg,which was under the reported threshold of the chlorine resistance for the rice and wheat.The pH in soil of the UAMF was also not changed significantly,but that of the ammonium chloride decreased by 0.88 units compared with the urea.[Conclusions] Taking into consideration both the yield and environmental benefit in the rice-wheat rotation system,the UAMF should be a promising N fertilizer for replacing urea or ammonium chloride in Taihu Lake region.