Cover cropping is a farming practice that may improve C sequestration and soil fertility, but these effects can vary under different edaphoclimatic conditions. The effects of including a winter gramineous cover crop (CC) in continuous soybeans were evaluated in three long-term experiments (8 yr) on one coarse-textured soil and two fine-textured soils in the Pampas region of Argentina. The impacts of CC on soil C sequestration, soil nutrient availability, soil organic C (SOC), and N contents of soil particle size fractions were also determined. The inclusion of CC only increased SOC stock by 3.1 Mg ha^-1 in the coarse-textured soil (CTS). The labile C fraction in the 0–5-cm depth increased in both the CTS and the fine-textured soils (FTS) by 263% and 93%, respectively. Soil N also increased in the labile fraction by 119% and 112% when a CC was used in the CTS and FTS soils, respectively. Moreover, the inclusion of a CC decreased soil P availability in one experiment (4.9 kg ha^-1) and increased soil manganese in two experiments (11 kg ha^-1 on average). The inclusion of a gramineous CC in a soybean monoculture increased the C balance, particularly in coarse-textured soils. Considering that soil N was similarly affected, the C/N ratio was not impacted.

中文翻译：

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通过在连续大豆中加入禾本科覆盖作物，土壤固碳和土壤肥力是否会增加？

覆盖种植是一种可以提高碳封存和土壤肥力的农业实践，但这些影响在不同的土壤气候条件下会有所不同。在阿根廷潘帕斯地区的一种粗质地土壤和两种细质地土壤上进行的三个长期试验（8 年）中，对在连续大豆中加入冬季禾本科覆盖作物 (CC) 的影响进行了评估。还确定了 CC 对土壤 C 固存、土壤养分有效性、土壤有机 C (SOC) 和土壤粒度级分 N 含量的影响。加入 CC 仅使 SOC 储量增加了 3.1 Mg ha ^-1在粗糙质地的土壤（CTS）中。在 CTS 和细质地土壤 (FTS) 中，0-5 厘米深度的不稳定 C 分数分别增加了 263% 和 93%。当在 CTS 和 FTS 土壤中使用 CC 时，土壤 N 的不稳定部分也分别增加了 119% 和 112%。此外，在一项实验中加入 CC 降低了土壤磷的有效性（4.9 kg ha ^-1），并在两项实验中增加了土壤锰（平均11 kg ha ^-1）。在大豆单一栽培中加入禾本科 CC 增加了 C 平衡，特别是在质地粗糙的土壤中。考虑到土壤 N 受到类似影响，C/N 比没有受到影响。