School of Water Conservancy and Civil Engineering, Northeast Agricultural University, Harbin, Heilongjiang 150030, China; Key Laboratory of Effective Utilization of Agricultural Water Resources of Ministry of Agriculture, Northeast Agricultural University, Harbin, Heilongjiang 150030, China; Heilongjiang Provincial Key Laboratory of Water Resources and Water Conservancy Engineering in Cold Region, Northeast Agricultural University, Harbin, Heilongjiang 150030, China.
School of Water Conservancy and Civil Engineering, Northeast Agricultural University, Harbin, Heilongjiang 150030, China; Key Laboratory of Effective Utilization of Agricultural Water Resources of Ministry of Agriculture, Northeast Agricultural University, Harbin, Heilongjiang 150030, China; Heilongjiang Provincial Key Laboratory of Water Resources and Water Conservancy Engineering in Cold Region, Northeast Agricultural University, Harbin, Heilongjiang 150030, China.
Sci Total Environ. 2023 Dec 20;905:167180. doi: 10.1016/j.scitotenv.2023.167180. Epub 2023 Sep 20.
Changes in the soil environment caused by winter warming is affecting the carbon and nitrogen cycles of seasonal freeze-thaw farmland soil. A field experiment was conducted in a seasonal freeze-thaw farmland soil of northeast China to investigate the effects caused from different levels of warming (W1 + 1.77 °C, W2 + 0.69 °C and C + 0 °C) on soil carbon and nitrogen dynamics, microbial biomass and greenhouse gases fluxes. During the early and middle winter, the contents of all kinds of soil carbon and nitrogen (Ammonium, nitrate, total nitrogen, dissolved organic carbon, readily oxidizable organic carbon and soil organic carbon) tended to increase with the increase of warming level, while during the late winter, their contents under different temperature treatments roughly present trend of W2 ≥C > W1. Except for the late thawing period, warming increased the contents of soil microbial biomass carbon and nitrogen, during the late thawing period, with the increase of warming level, MBC and MBN decreased significantly. Warming would stimulate the release of greenhouse gases from soil. But due to the differences of soil environmental conditions in each period and soil nutrient dynamics under different treatments, which made the effects of different levels of warming on soil GHGs fluxes in different periods are different. Our study suggested that low-level warming improved the availability of soil carbon and nitrogen, increased the contents of microbial biomass and greenhouse gas emissions. However, although high-level winter warming showed a similar phenomenon in the early and middle winter to the low-level warming, during the late winter, high-level warming increased soil nutrients loss and broke the seasonal coupling relationship between crop nutrient acquisition and soil microbial nutrient supply, and even led to the adaptation of soil CO release to it. This is of great significance for exploring the carbon and nitrogen cycle mechanisms of global terrestrial ecosystem.
冬季变暖引起的土壤环境变化正在影响季节性冻融农田土壤的碳氮循环。在中国东北的季节性冻融农田土壤中进行了田间试验，以研究不同水平的变暖（W1+1.77°C、W2+0.69°C 和 C+0°C）对土壤碳氮动态、微生物生物量和温室气体通量的影响。在初冬和仲冬，各种土壤碳氮含量（铵、硝酸盐、总氮、溶解有机碳、易氧化有机碳和土壤有机碳）随着变暖水平的增加而增加，而在晚冬，不同温度处理下的含量大致呈现 W2≥C＞W1 的趋势。除了晚融期外，变暖增加了土壤微生物生物量碳和氮的含量，在晚融期，随着变暖水平的增加，MBC 和 MBN 显著降低。变暖会刺激土壤温室气体的释放。但由于每个时期土壤环境条件的差异和不同处理下土壤养分动态的差异，使得不同水平的变暖对不同时期土壤 GHGs 通量的影响不同。我们的研究表明，低水平变暖提高了土壤碳氮的有效性，增加了微生物生物量的含量和温室气体排放。然而，尽管高水平冬季变暖在初冬和仲冬与低水平变暖表现出相似的现象，但在晚冬，高水平变暖增加了土壤养分的损失，打破了作物养分吸收和土壤微生物养分供应之间的季节性耦合关系，甚至导致土壤 CO 释放适应它。这对于探索全球陆地生态系统的碳氮循环机制具有重要意义。
