Previous studies simply focused on determining nitrous oxide (N2O) emissions from the soil under different tillage operations and nitrogen (N) fertilizations without considering crop yield. Therefore, the objective of this study was to determine the effects of different tillage operations and N fertilizations on N2O emissions and crop yield from upland soil. Two different tillage operations [conventional tillage (CT) and no-tillage (NT)] and N fertilizations [without urea (WOU) and with 186 kg N ha−1 of urea (WU)] were established in a randomized block design with three replications on upland soil. Maize (Zea mays) was cultivated from 6th July to 4th October, 2018 (year 1), and from 15th April to 26th July, 2019 (year 2). The daily N2O flux did not peak soon after tillage operation and N fertilization, but it was more related to the change in water-filled pore space (WFPS). The mean value of WFPS across N fertilizations and seasons (years) was higher in CT than in NT. The changes of nitrification and denitrification rates could be attributed to the differences in WFPS between CT and NT. Nitrification was the predominant process producing N2O with CT, but denitrification was with NT. The application of urea increased cumulative N2O emissions, while CT also increased it compared with NT. The order of the mean values of cumulative N2O emissions across seasons from the highest to the lowest was as follows: CT + WU (7.12 kg N2O ha−1 year−1) > NT + WU (5.69 kg N2O ha−1 year−1) ≥ CT + WOU (5.02 kg N2O ha−1 year−1) > NT + WOU (4.24 kg N2O ha−1 year−1). Tillage operation did not affect the grain yield of maize or yield-scaled N2O emissions (YSNE). However, the application of urea increased the grain yield of maize and decreased YSNE, implying it could reduce N2O emission per unit of maize grain production. No-tillage management did not decrease YSNE value compared to CT operation, but N fertilization significantly decreased YSNE in the current study.

中文翻译：

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氮肥和耕作操作对旱地土壤一氧化二氮排放量和玉米产量的影响

以前的研究仅着重于确定在不同耕作操作和施氮（N）下土壤中的一氧化二氮（N2O）排放，而没有考虑作物产量。因此，本研究的目的是确定不同耕作和施氮对旱地土壤N2O排放和农作物产量的影响。在随机区组设计中，建立了两种不同的耕作方法[常规耕种（CT）和免耕（NT）]和N施肥[无尿素（WOU）和186 kg N ha-1尿素（WU）]在高地土壤上复制。玉米（Zea mays）于2018年7月6日至10月4日（第1年）和2019年4月15日至7月26日（第2年）种植。耕作和施氮后，N2O的日通量并没有很快达到峰值，但它与充水孔隙空间（WFPS）的变化有关。CT上不同氮肥和不同季节（年）的WFPS平均值高于NT。硝化和反硝化率的变化可能归因于CT和NT之间WFPS的差异。硝化是利用CT生产N2O的主要过程，而硝化是利用NT进行的。尿素的使用增加了累积的N2O排放量，而CT与NT相比也增加了累积量。从最高到最低的各个季节的累积N2O排放平均值的顺序如下：CT + WU（7.12千克N2O ha-1年-1）> NT + WU（5.69千克N2O ha-1年-1 ）≥CT + WOU（5.02千克N2O ha-1年-1）> NT + WOU（4.24千克N2O ha-1年-1）。耕作操作不会影响玉米的籽粒产量或产量成比例的N2O排放量（YSNE）。然而，尿素的施用增加了玉米的籽粒产量，降低了YSNE，这意味着它可以减少每单位玉米产量的N2O排放。与CT手术相比，免耕管理并未降低YSNE值，但在当前研究中，氮肥显着降低了YSNE。