Irrigated forage production systems are intensive and highly exhaustive on nutrients. Integration of cover crops in irrigated forage crop rotation could be a strategy to increase soil organic carbon (SOC) storage and improve nutrient cycling. However, there is a lack of comprehensive information on cover cropping strategies for improving soil health, SOC sequestration, and nutrient cycling in forage-based crop rotations in arid and semi-arid environments. A four-year study (2018–2022) evaluated the effects of cover crops on soil carbon and nitrogen (N) pools and nutrient concentrations in no-tillage corn ( L.) – sorghum [ (L.) Moench] rotation. We aimed to quantify the response of SOC and N pools and other nutrients with cover cropping and elucidate their SOC sequestration potential under a forage-based crop rotation in semi-arid environments. Cover crop treatments included a mixture of grasses, brassicas, and legumes (GBL), grasses and brassicas (GB), grasses and legumes (GL), and no cover crop (NCC). Soil samples were collected from 0–80 cm profiles and measured for potentially mineralizable carbon (PMC), SOC, total labile N (TLN), inorganic N, available Phosphorus (P), Potassium (K), and other macro and micronutrients as soil health indicators. Soil PMC content under GB treatment was greater than NCC at 10–20 (85.5%) and 20–40 (70.5%) cm soil depth . The SOC was greater under GBL than under NCC at 0–60 cm (12 to 43%), while TLN was greater under GL than NCC at 0–20 cm depth (27 to 35%). The GBL mixture also enhanced soil N, P, and K within the upper 0–10 cm soil layer. The SOC stock at 0–80 cm depth under cover crops was 7–22% greater than under NCC, resulting in SOC sequestration of 1.5–2.3 Mg C ha y in cover crop plots. Cover cropping can increase SOC sequestration in irrigated cropping systems in semi-arid environments. Considerable increases in labile C and N components in the soil profile with cover cropping indicate long-term improvement in soil health and productivity through increased total SOC storage and improved nutrient cycling.

中文翻译：

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土壤剖面碳固存和养分响应随灌溉牧草轮作中覆盖作物的变化而变化

灌溉牧草生产系统是集约化且养分高度耗尽的。将覆盖作物纳入灌溉饲料作物轮作可能是增加土壤有机碳（SOC）储存和改善养分循环的一项策略。然而，缺乏关于干旱和半干旱环境中基于饲料的作物轮作中改善土壤健康、SOC固存和养分循环的覆盖种植策略的全面信息。一项为期四年的研究（2018-2022）评估了覆盖作物对免耕玉米（L.）-高粱[（L.）Moench]轮作中土壤碳和氮（N）库以及养分浓度的影响。我们的目的是量化 SOC 和氮库以及其他养分对覆盖作物的响应，并阐明半干旱环境中基于饲料的作物轮作下它们的 SOC 固存潜力。覆盖作物处理包括草、芸苔属和豆类的混合物（GBL）、草和芸苔属（GB）、草和豆类（GL）以及无覆盖作物（NCC）。从 0-80 cm 剖面采集土壤样品，并测量潜在可矿化碳 (PMC)、SOC、总不稳定氮 (TLN)、无机氮、有效磷 (P)、钾 (K) 以及土壤中的其他常量和微量营养素健康指标。GB处理下土壤PMC含量在10-20（85.5%）和20-40（70.5%）cm土层深度处高于NCC。在 0-60 cm 深度处，GBL 下的 SOC 比 NCC 下的要高（12% 到 43%），而在 0-20 cm 深度处，GL 下的 TLN 比 NCC 下的要大（27% 到 35%）。GBL 混合物还增强了上部 0-10 厘米土层内的土壤氮、磷和钾。覆盖作物下 0–80 厘米深度的 SOC 储量比 NCC 下高 7–22%，导致覆盖作物地块中 SOC 固存为 1.5–2.3 Mg C 干草。覆盖种植可以增加半干旱环境中灌溉种植系统的有机碳固存。覆盖种植使土壤剖面中的不稳定碳和氮成分显着增加，这表明通过增加总有机碳储存量和改善养分循环，可以长期改善土壤健康和生产力。