Soil organic matter (SOM) is considered an important indicator of soil quality, which can be impacted by crop production practices such as tillage. In this study, two long‐term tillage regimes (conventional tillage [CT] and no tillage [NT], conducted for 36 years) were compared in continuous sorghum production in a sub‐tropical environment in southeast Texas. The positive effects of long‐term NT practice were more conspicuous at the soil surface compared with the deeper soil profiles. The SOC was greater (1.5 t C ha⁻¹ greater) in the NT system compared with the CT system. Results from an incubation study indicate that the rate of C‐min at 0–5 cm soil depth was significantly greater (164 μg of CO₂–C g⁻¹ of soil greater) in NT than that of CT, but this trend was reversed at 10–20 cm depth wherein the C‐min rates were 106 μg of CO₂–C g⁻¹ of soil greater in CT compared with NT, which is likely because of soil disturbance during the study. Soil cumulative CO₂‐C emissions were greater in the CT system (7.28 g m⁻²) than in the NT system (5.19 g m⁻²), which is primarily attributed to high soil temperature conditions in the CT system. Sorghum grain yield however was not influenced by the differences in SOC content in this long‐term experiment. Overall, the present study found that long‐term conservation tillage improved SOC stock and reduced carbon loss, thus had a positive impact on soil health and sustainability.

中文翻译：

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亚热带环境下长期（免耕）高粱生产（36年）下的土壤碳改善

土壤有机质（SOM）被认为是土壤质量的重要指标，它可能会受到耕作等作物生产实践的影响。在这项研究中，比较了德克萨斯州东南部亚热带环境中连续高粱生产中的两种长期耕作制度（常规耕作[CT]和不耕作[NT]，进行了3​​6年）。与更深的土壤剖面相比，长期的NT实践对土壤表面的影响更为明显。与CT系统相比，NT系统中的SOC更大（大1.5 t C ha ^-1）。孵化研究的结果表明，在土壤深度为0-5 cm时C-min的速率显着更高（164μgCO ₂ -C g ^-1NT的土壤比CT的土壤大），但是这种趋势在10–20 cm深度处被逆转，其中CT的C-min速率是CT的土壤CO ₂ -C g ^-1比CT的土壤大，这比NT大。可能是由于研究期间的土壤干扰。CT系统（7.28 g m ^-2）的土壤累积CO ₂ -C排放量大于NT系统（5.19 g m ^-2）），这主要归因于CT系统中土壤温度高的条件。但是，在此长期实验中，高粱的籽粒产量不受SOC含量差异的影响。总体而言，本研究发现，长期的保护性耕作可提高SOC储量并减少碳损失，因此对土壤健康和可持续性具有积极影响。