Maier Regine, Hörtnagl Lukas, Buchmann Nina
Institute of Agricultural Sciences, ETH Zurich, Universitätstrasse 2, 8092 Zurich, Switzerland.
Nutr Cycl Agroecosyst. 2025;130(2):161-175. doi: 10.1007/s10705-024-10395-0. Epub 2025 Feb 5.
Global agriculture is the largest anthropogenic source for nitrous oxide (NO) emissions. During crop rotations, periods with arable soils without crops, thereafter called "bare soils" are often impossible to avoid after the crop is harvested, prior to sowing of the next crop. However, such periods are underrepresented in studies focussing on NO emissions. Here, we present continuous, high-temporal-resolution NO fluxes during bare soil periods after four major crops, using the eddy-covariance technique at two sites in Switzerland. Overall, periods with bare soil were net sources for NO as well as for carbon dioxide (CO) and methane (CH). Daily average sums of NO emissions varied between 10 ± 2 and 38 ± 5 g NO-N ha d after the respective rapeseed, winter wheat, pea, and maize harvests. While CO emissions contributed 86-96% to the total GHG budgets, NO fluxes accounted for 2% after pea, but for 10-12% after rapeseed, winter wheat, and maize. In contrast, CH fluxes were negligible (< 2%). NO fluxes during bare soil periods increased for all cropland sites with increasing water-filled pore space, particularly at high soil temperatures. Thus, our study emphasizes the significance of avoiding bare soil periods to mitigate NO emissions from croplands.
The online version contains supplementary material available at 10.1007/s10705-024-10395-0.
全球农业是一氧化二氮（N₂O）排放的最大人为来源。在作物轮作期间，收获作物后、播种下一季作物之前，经常不可避免地会出现没有作物的可耕地时期，此后称为“裸土”时期。然而，在关注N₂O排放的研究中，这些时期的代表性不足。在此，我们利用瑞士两个地点的涡度协方差技术，展示了四种主要作物收获后裸土时期连续的、高时间分辨率的N₂O通量。总体而言，裸土时期是N₂O以及二氧化碳（CO₂）和甲烷（CH₄）的净排放源。在各自的油菜、冬小麦、豌豆和玉米收获后，N₂O排放的日平均总量在10±2至38±5克N-N·公顷⁻¹·天⁻¹之间变化。虽然CO₂排放在温室气体总预算中占86%-96%，但豌豆收获后N₂O通量占2%，而油菜、冬小麦和玉米收获后占10%-12%。相比之下，CH₄通量可忽略不计（<2%）。随着土壤孔隙含水量增加，所有农田站点裸土时期的N₂O通量均增加，尤其是在土壤温度较高时。因此，我们的研究强调了避免裸土时期以减少农田N₂O排放的重要性。
在线版本包含可在10.1007/s10705-024-10395-0获取的补充材料。
