College of Agronomy and Biotechnology, China Agricultural University, Beijing 100193, China.
Department of Agroecology, Aarhus University, 8830 Tjele, Denmark.
Sci Total Environ. 2020 Sep 10;734:139269. doi: 10.1016/j.scitotenv.2020.139269. Epub 2020 May 8.
Climatic changes, such as global warming and altered precipitation are of major environmental concern. Given that ecosystem processes are strongly regulated by temperature and water content, climate changes are expected to affect the carbon (C) and nitrogen (N) cycles, especially in agricultural systems. However, the interactive effects of soil warming and increased precipitation on greenhouse gas emissions are poorly understood, particularly in the North China Plain (NCP). Therefore, a field experiment was conducted over two spring maize seasons (May-Sept.) in 2018 and 2019. Two levels of temperature (T0: ambient temperature; T1: increase on average of 4.0 °C) combined with two levels of precipitation (W0: no artificial precipitation; W1: +30% above ambient precipitation) were carried out in the NCP. Our results showed that soil warming significantly promoted cumulative NO and CO emissions by 49% and 39%, respectively. Additionally, increased precipitation further enhanced the NO and CO emissions by 54% and 14%, respectively. This suggests that high soil temperature and water content have the capacity to stimulate microbial activities, and thus accelerate the soil C and N cycles. Soil warming increased CH uptake by 293%, but increased precipitation had no effect on CH fluxes. Overall, soil warming and increased precipitation significantly enhanced the GHG budget by 39% and 16%, respectively. This study suggests that climate warming will lead to enhanced GHG emissions in the spring maize season in the NCP, while increased precipitation in the future may further stimulate GHG emissions in a warming world.
气候变化，如全球变暖及降水改变，是主要的环境关注点。由于生态系统过程受到温度和含水量的强烈调节，预计气候变化将影响碳（C）和氮（N）循环，特别是在农业系统中。然而，土壤增温和增加降水对温室气体排放的交互影响还了解甚少，特别是在华北平原（NCP）。因此，本研究在 2018 年和 2019 年的两个春季玉米季（5 月至 9 月）进行了田间实验。在 NCP 中进行了两个温度水平（T0：环境温度；T1：平均升高 4.0°C）和两个降水水平（W0：无人工降水；W1：比环境降水多 30%）的组合。结果表明，土壤增温分别显著促进了累积 NO 和 CO 排放增加 49%和 39%。此外，增加降水分别进一步增强了 NO 和 CO 排放增加 54%和 14%。这表明高温和高含水量有能力刺激微生物活动，从而加速土壤 C 和 N 循环。土壤增温使 CH 吸收增加了 293%，但增加降水对 CH 通量没有影响。总体而言，土壤增温和增加降水分别显著增强了 GHG 预算 39%和 16%。本研究表明，气候变暖将导致 NCP 春季玉米季温室气体排放增加，而未来增加降水可能会在变暖的世界中进一步刺激温室气体排放。
