Jiangsu Key Laboratory of Coal-based Greenhouse Gas Control and Utilization, China University of Mining and Technology, Xuzhou, Jiangsu, 221008, China; School of Agriculture and Biology, Shanghai Jiao Tong University, Shanghai, 200240, China.
School of Agriculture and Biology, Shanghai Jiao Tong University, Shanghai, 200240, China.
J Environ Manage. 2021 Aug 15;292:112691. doi: 10.1016/j.jenvman.2021.112691. Epub 2021 May 8.
To improve grain production capacity, many areas in the world are shifting from rainfed agriculture to irrigated agriculture. One example of such land consolidation is dryland-to-paddy conversion. The conversion of land use pattern largely affects the stability of farmland soil, especially the soil carbon cycle. However, the mutual feedback mechanisms between carbon flux variation and environmental factors during the farmland consolidation process are still poorly known. Located in the Huang-Huai-Hai Plain China, Xuzhou is a typical area where dryland-to-paddy conversion are most widely distributed. Therefore, in this study, we have carried out dryland-to-paddy conversion by setting up two isolated rectangular fields one group planting corn in dryland (DL) and another group planting in paddy field (PF) in Xuzhou. Here, we determined the effect of dryland-to-paddy consolidation on soil CO flux in two isolated rectangular fields - the dryland (DL) cultivated with corn and the paddy field (PF) cultivated with rice. Our results showed that the soil carbon flux and temperature followed similar unimodal curves with greater soil CO flux of in PF than in DL. Surprisingly, the land conversion significantly reduced soil microbial biomass carbon and easily oxidized organic carbon by 28.55% and 29.09%, respectively. The structural equation modeling results demonstrated that the changes in soil environmental factors, including temperature, and fungal OTU numbers, were the primary drivers for the soil CO flux and soil carbon pool (P < 0.05). Overall, this study improves the understanding of the ecological impact of dryland-to-paddy conversion, providing insights into low-carbon agriculture and climate mitigation.
为提高粮食生产能力，世界许多地区正在从雨养农业向灌溉农业转变。旱地改水田就是土地整治的一个例子。土地利用方式的转变在很大程度上影响着农田土壤的稳定性，尤其是土壤碳循环。然而，在农田整治过程中，碳通量变化与环境因素之间的相互反馈机制仍知之甚少。中国黄淮海平原的徐州市是旱地改水田分布最广泛的典型地区。因此，本研究通过在徐州市建立两个隔离的长方形地块，一组种植旱地玉米（DL），另一组种植水田水稻（PF），进行旱地改水田的转换。在这里，我们测定了两个隔离的长方形地块——旱地（DL）种植玉米和水田（PF）种植水稻的旱地改水田对土壤 CO 通量的影响。结果表明，土壤碳通量和温度随时间变化呈现相似的单峰曲线，PF 的土壤 CO 通量大于 DL。令人惊讶的是，土地转换显著降低了土壤微生物生物量碳和易氧化有机碳，分别降低了 28.55%和 29.09%。结构方程模型的结果表明，土壤环境因素（包括温度和真菌 OTU 数量）的变化是土壤 CO 通量和土壤碳库变化的主要驱动因素（P < 0.05）。总之，本研究提高了对旱地改水田生态影响的认识，为低碳农业和气候缓解提供了新的思路。
