摘要:氮肥深施能有效减少土壤氨挥发，然而目前国内外关于小麦-玉米轮作体系氮肥深施缺乏周年系统性研究。本试验于2018年10月—2019年10月在中国科学院栾城农业生态系统试验站小麦-玉米轮作农田进行，利用动态箱法研究不同深施模式氨挥发损失率、氨挥发特征，旨在探讨冬小麦-夏玉米轮作体系下土壤氨排放对氮肥深施的响应，为减少农业源氨排放和优化农田施肥提供理论依据。试验设置5个处理：不施肥(CK)、常规肥料表施(T1)、缓释肥表施(T2)、缓释肥基追肥分层深施(T3)、缓释肥一次性分层深施(T4)。结果表明：氨挥发主要发生在玉米追肥季，占全年氨挥发量的84.84%；T1、T2、T3和T4处理的周年氨挥发累积量分别为22.75 kg·hm-2、6.17 kg·hm-2、2.25 kg·hm-2和0.55 kg·hm-2，分别占总施肥量的4.86%、1.32%、0.48%和0.13%。与常规肥料表施(T1)相比，缓释肥处理(T2、T3和T4)分别降低72.88%、90.11%和97.32%的氨挥发损失；一次性深施处理(T4)能避开土壤氨高挥发期，周年氨挥发累积量与不施肥处理(0.43 kg·hm-2)没有显著差异，且显著低于表施处理。CK、T1、T2、T3和T4全年产量分别为8.31 t·hm-2、13.20 t·hm-2、12.66 t·hm-2、14.42 t·hm-2和14.22 t·hm-2；与常规肥料表施(T1)相比，缓释肥深施(T3和T4)均可提高作物产量，分别增产9.25%和7.75%。而缓释肥表施(T2)产量略有降低。综合考虑土壤氨排放和作物产量，缓释肥表施(T2)可以显著降低土壤氨挥发，但是作物产量不稳定；而氮肥深施(T3、T4)能在保证作物高产的基础上显著降低土壤氨排放，是一种高效、简便、环境友好的施肥方式。
关键词:氨挥发/
氮肥深施/
单位产量氨排放强度/
缓释肥/
冬小麦-夏玉米轮作
Abstract:The deep application of nitrogen fertilizers can reduce soil ammonia volatilization, but no annual systematic study in a winter wheat/summer maize rotation system exists. Nitrogen fertilizer was deeply applied to soil from a winter wheat/summer maize rotation system to determine the effects on ammonia emissions and optimize farmland fertilization. Five treatments were used from October 2018 to October 2019:no fertilization (CK), conventional fertilizer surface-application (T1), slow-release fertilizer surface-application (T2), twice layered deep-application of slow-release fertilizer (T3), and single layered deep-application of slow-release fertilizer (T4). Ammonia volatilization primarily occurred in the corn top-dressing season and accounted for 84.84% of the annual ammonia volatilization. The cumulative amounts of annual ammonia volatiles were 22.75 (T1), 6.17 (T2), 2.25 (T3), and 0.55 kg·hm-2(T4), accounting for 4.86%, 1.32%, 0.48%, and 0.16% of the total fertilizer application, respectively. The slow-release fertilizer treatments reduced the ammonia volatilization loss by 72.88% (T2), 90.11% (T3), and 96.30% (T4) compared to T1. The single deep application treatment (T4) avoided the summertime high soil ammonia volatilization period, and the cumulative annual ammonia emissions were comparable to the unfertilized emissions (0.43 kg·hm-2). The annual yields were 8.31 (CK), 13.20 (T1), 12.66 (T2), 14.42 (T3), 14.22 (T4) t·hm-2; and compared with T1, the slow-release fertilizer deep application increased the crop yield by 9.25% (T3) and 7.75% (T4). The surface application of slow-release fertilizer (T2) slightly decreased the yield but significantly reduced the ammonia volatilization amount. In conclusion, the deep application of slow-release nitrogen fertilizer improved crop yield and reduced soil ammonia emissions, and was shown to be a simple, efficient, and environment-friendly fertilization method.
Key words:Ammonia volatilization/
Nitrogen deep application/
Ammonia discharge per unit output/
Slow-release fertilizer/
Winter wheat-summer maize rotation
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