ABSTRACT

Soil organic C (SOC) pools have various stabilization mechanisms and turnover times, which change with depth and are highly influenced by land use. Total SOC (TOC), particulate organic carbon (POC), mineral-associated organic carbon (MOC), and carbon management index (CMI) were used as indicators to compare cropland with manure application (CM) and continuous pasture (CP) to a hardwood forest (HF) at soil 0–10 and 10–25 cm depths. Land use, depth, and their interactions had significant influences on TOC, POC, MOC, MOC/TOC ratio, and CMI except for land use main effect on TOC. Compared to HF and CP soils, CM showed significantly larger POC (12.4 g kg⁻¹) and smaller MOC (8.36 g kg⁻¹) at 10–25 cm; CM had significantly smaller TOC (32.3 g kg⁻¹) and MOC at 0–10 cm (11.81 g kg⁻¹). CM soil at 10–25 cm had higher soil quality and SOC lability as indicated by a significantly larger CMI value (419.2), while CP soil had lower soil quality and SOC lability at 0–10 cm (83.7) and 10–25 cm (73.6) compared to HF soil. This study implied high sensitivity of cropland and pasture surface SOC to degrade under disturbance, which implies that better management strategies are still needed to improve soil quality for these agricultural systems.

摘要

土壤有机碳 (SOC) 池具有各种稳定机制和周转时间，随深度变化，受土地利用的影响很大。以总有机碳 (TOC)、颗粒有机碳 (POC)、矿物相关有机碳 (MOC) 和碳管理指数 (CMI) 作为指标，将农田施肥 (CM) 和连续牧草 (CP) 与土壤深度为 0-10 和 10-25 厘米的阔叶林 (HF)。除了土地利用对 TOC 的主要影响外，土地利用、深度及其相互作用对 TOC、POC、MOC、MOC/TOC 比和 CMI 有显着影响。与 HF 和 CP 土壤相比，CM在 10-25 cm 处显示出明显更大的 POC (12.4 g kg ^-1 ) 和更小的 MOC (8.36 g kg ^-1 )；CM 的 TOC 明显更小（32.3 g kg ^-1) 和 MOC 在 0–10 cm (11.81 g kg ^-1 )。CM 土壤在 10-25 cm 处具有较高的土壤质量和 SOC 不稳定性，如显着较大的 CMI 值（419.2）所示，而 CP 土壤在 0-10 cm（83.7）和 10-25 cm 处具有较低的土壤质量和 SOC 不稳定性（ 73.6) 与 HF 土壤相比。该研究表明农田和牧场表面 SOC 在干扰下对降解具有高度敏感性，这意味着仍然需要更好的管理策略来改善这些农业系统的土壤质量。