Abstract Previous studies have shown that the use of zinc (Zn) chelate fertilizers combined with a nitrogen (N) fertilizer (urea) can lead to both agronomic (i.e., yields and Zn and N biofortification due to the synergies between both nutrients) and environmental (i.e., by reducing the emissions of nitrous oxide, N2O, derived from N fertilization) benefits under rainfed semi-arid conditions. However, little is known about the effect of Zn-N co-fertilization on greenhouse gas (GHG) emissions or soil microbial processes involved in N2O fluxes under non-flooded irrigated conditions (during the dry season). Under these conditions, water-filled pore space continuously fluctuates following a periodic pattern and soil temperatures are in the optimum range for soil microorganisms. In this context, a field experiment was conducted using a maize (Zea mays L.) crop treated with two N levels (no N application and 120 kg N ha−1 as urea), and three Zn sources (no Zn application, Zn sulphate, and Zn applied with a mixture of chelating compounds, DTPA-HEDTA-EDTA). Nitrous oxide, methane (CH4) and carbon dioxide (CO2) fluxes were measured using opaque chambers, as well as the total abundances of soil bacteria, archaea and nitrifier and denitrifier communities. Zn-N co-fertilization increased cumulative N2O emissions from 0.36 kg N-N2O ha−1 (for urea combined with Zn chelates) to 0.76 kg N-N2O ha−1 (for urea combined with Zn sulphate), with respect to urea without Zn application. The N2O emission factors were lower (0.34%–0.72%) than the IPCC default value of 1%. Total abundances of the nosZ denitrification gene, which is involved in the reduction in N2O to dinitrogen (N2), were reduced by 75% on average in the plots that received Zn fertilizers. This reduction may explain the higher N2O emissions in these treatments. In contrast with the case with non-irrigated crops, Zn-N co-fertilization cannot be recommended as a strategy to mitigate N2O emissions in irrigated maize under semi-arid conditions, despite of the enhancement of Zn availability in soil.

中文翻译：

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锌氮复合施肥对灌溉玉米田中 N2O 排放和微生物群落的影响

摘要 先前的研究表明，将锌 (Zn) 螯合肥料与氮 (N) 肥料（尿素）结合使用可导致农艺（即产量和 Zn 和 N 生物强化，由于两种养分之间的协同作用）和环境（即，通过减少氮肥施肥产生的一氧化二氮、N2O 的排放）在雨养半干旱条件下的益处。然而，在非淹水灌溉条件下（旱季），Zn-N 共施肥对温室气体 (GHG) 排放或涉及 N2O 通量的土壤微生物过程的影响知之甚少。在这些条件下，充满水的孔隙空间按照周期性模式不断波动，土壤温度处于土壤微生物的最佳范围内。在这方面，使用玉米（Zea mays L. ) 用两种 N 水平（不施氮和 120 kg N ha-1 作为尿素）和三种锌源（不施锌、硫酸锌和使用螯合化合物 DTPA-HEDTA-EDTA 的混合物施用的 Zn）处理的作物. 使用不透明室测量一氧化二氮、甲烷 (CH4) 和二氧化碳 (CO2) 通量，以及土壤细菌、古细菌、硝化菌和反硝化菌群落的总丰度。Zn-N 联合施肥将 N2O 的累积排放量从 0.36 kg N-N2O ha-1（尿素与锌螯合物结合）增加到 0.76 kg N-N2O ha-1（尿素与硫酸锌结合），相对于不施肥的尿素而言锌的应用。N2O 排放因子低于 IPCC 缺省值 1%（0.34%–0.72%）。nosZ 反硝化基因的总丰度，该基因参与将 N2O 还原为二氮 (N2)，在施用锌肥的地块中平均减少了 75%。这种减少可以解释这些处理中较高的 N2O 排放。与非灌溉作物的情况相反，尽管提高了土壤中锌的有效性，但不建议将 Zn-N 复合施肥作为在半干旱条件下减少灌溉玉米中 N2O 排放的策略。