Tillage activates iron to prevent soil organic carbon loss following forest conversion to cornfields in tropical acidic red soils
Tillage activates iron to prevent soil organic carbon loss following forest conversion to cornfields in tropical acidic red soils
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热带酸性红壤森林转变为玉米地后，耕作可激活铁，防止土壤有机碳流失
DOI：
10.1016/j.scitotenv.2020.143253
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发表时间：
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影响因子：
9.8
通讯作者：
Ruiqi An
中科院分区：
文献类型：
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作者：
Mingming Zong;Chen Lin;Shiyu Li;Haixia Li;Changqun Duan;Changhui Peng;Yongxing Guo;Ruiqi An
以往的研究表明，森林砍伐和种植玉米导致土壤有机碳（SOC）的损失。然而，这在酸性红壤地区并非不可避免。我们选择了中国西南地区种植了34年的6块玉米地和相邻的林地。利用结构方程模型，确定了11个土层中有利于土壤有机碳储存的42个土壤环境因子和土壤有机碳含量，并按层次（0-40、40-100和100-140 cm）评价了它们的相对权重。结果表明，退耕还林后，土壤有机碳密度在各层均未发生变化。在酸性红壤中，活性铁（FeO）、土壤含水量、氮素和pH是影响土壤有机碳储量的主要土壤环境因子。在0-40 cm土层，与林地相比，农田由于耕作促进了铁的活化，其FeO的贡献显著增加（增加了11.65%），而氮素的贡献显著降低（减少了9.65%）。在100-140 cm土层，土壤环境因子的贡献与森林系统相似，但玉米地pH值显著升高（增加21.5%）可能是由于氢离子的淋溶所致。虽然玉米地耕作造成0-40 cm土层氮素的流失，但Fe ~（2+）的增加促进了铁与土壤有机碳的结合，避免了土壤有机碳的流失。
Previous studies have shown that deforestation and planting of corn resulted in the loss of soil organic carbon (SOC). However, this is not inevitable in regions with acidic red soil. We selected six cornfields that have been planted for 34 years and adjacent forest plots in southwest China. Using a structural equation model, we identified the SOC contents and 42 soil environmental factors in 11 soil layers that are conducive to SOC storage, and evaluated their relative weights hierarchically (0–40, 40–100, and 100–140 cm). Our results surprisingly indicated that after forest had been converted into cornfield, the SOC density did not change in any layer. In acidic red soil, reactive iron (Feo), soil water content, nitrogen, and pH were the main soil environmental factors that affected the storage of SOC. In the 0–40 cm soil layer, compared to forests, the contribution of Feoin cornfields increased significantly (by 11.65%), due to farming promoting the activation of iron, while the contribution of nitrogen decreased significantly (by 9.65%). In the 100–140 cm soil layer, the contribution of soil environmental factors was similar to that in the forest system, but the pH in cornfields increasing significantly (by 21.5%) may result from the leaching of hydrogen ions. Although the cultivation of cornfields caused a loss of nitrogen in the 0–40 cm soil layer, the increase in Feopromoted combination of iron and soil organic carbon, avoiding the soil layer from SOC loss.