Uwamahoro Hilarie, Kpomblekou-A Kokoasse, Mortley Desmond, Quarcoo Franklin
Department of Agricultural and Environmental Sciences, Tuskegee University, Tuskegee, AL, 36088, USA.
Heliyon. 2023 Mar 14;9(3):e14529. doi: 10.1016/j.heliyon.2023.e14529. eCollection 2023 Mar.
Soil organic carbon (SOC) is an important property that influences soil chemical, physical, and biochemical processes and is a key indicator of soil health. Rapid decomposition of crop residues incorporated into soil reduces the potential of carbon (C) sequestration in the Southeast United States where SOC is very low rending residue management very critical. We investigated the C contents and the decomposition of cultivars of popular organic vegetable crops [southern pea ( squash (), sweet potato [) ] and tomato (] in two soils under laboratory conditions. The C contents of the crop residues were determined by using a wet chemistry method. A non-linear regression model was used to determine the potentially mineralizable C (C) and the first-order rate constant (k) of the decomposition following incubation of soils treated with the vegetable crop residues for 30 days at room temperature. The average C contents varied between 304 and 437 g kg. On average, the sweet potato cultivars showed a greater C (19.4 g C kg) in Cecil soil than in Hartsells soil while tomato cultivars showed the least C (15.9 g C kg) in Hartsells soil. The k values showed that squash cultivars decomposed faster (0.106 day1) than any other crop, whereas southern pea cultivars decomposed the least in Cecil and Hartsells soils. Strong relationships between C, k, and C/N were established. Organic growers are environmentally conscious framers who wants to mitigate the greenhouse effect and global warming by adopting cropping systems that would sequester more C into the soil. Thus, identifying and selecting vegetable crop cultivars that would incorporate more C in soil is of a great interest to them. These findings have potentials of guiding organic growers in selecting crop cultivars that would increase OC sequestration in soils.
土壤有机碳（SOC）是一种重要特性，它影响土壤化学、物理和生物化学过程，是土壤健康的关键指标。在美国东南部，土壤有机碳含量极低，将作物残茬纳入土壤的快速分解降低了碳固存潜力，因此残茬管理至关重要。我们在实验室条件下，研究了两种土壤中常见有机蔬菜作物[南方豌豆（）、南瓜（）、红薯[）]和番茄（]品种的碳含量及分解情况。采用湿化学法测定作物残茬的碳含量。将蔬菜作物残茬处理过的土壤在室温下培养30天后，用非线性回归模型确定潜在矿化碳（C）和分解的一级速率常数（k）。平均碳含量在304至437克/千克之间变化。平均而言，红薯品种在塞西尔土壤中的碳含量（19.4克碳/千克）高于哈茨尔斯土壤，而番茄品种在哈茨尔斯土壤中的碳含量最低（15.9克碳/千克）。k值表明，南瓜品种分解速度更快（0.106天-1），高于其他任何作物，而南方豌豆品种在塞西尔和哈茨尔斯土壤中的分解最少。建立了碳、k和碳氮比之间的强相关性。有机种植者是注重环境的农民，他们希望通过采用能将更多碳固存到土壤中的种植系统来减轻温室效应和全球变暖。因此，识别和选择能在土壤中固存更多碳的蔬菜作物品种对他们来说非常重要。这些研究结果有可能指导有机种植者选择能增加土壤有机碳固存的作物品种。
