There are few reliable data sets to inspire confidence in policymakers that soil or-ganic carbon (SOC) can be measured on farms. We worked with farmers in the Tamar Valley region of southwest England to select sampling sites under similar conditions (soil type, aspect and slope) and management types. Topsoils (2–15 cm) were sam-pled in autumn 2015, and percentage soil organic matter (%SOM) was determined by loss on ignition and used to calculate %SOC. We also used the stability of mac-roaggregates in cold water (WSA) (‘soil slaking’) as a measure of ‘soil health’ and investigated its relationship with SOC in the clay-rich soils. %SOM was significantly different between management types in the order woodland (11.1%) = permanent pasture (9.5%) > ley-arable rotation (7.7%) = arable (7.3%). This related directly to SOC stocks that were larger in fields under permanent pasture and woodland com-pared with those under arable or ley-arable rotation whether corrected for clay con-tent (F = 8.500, p < .0001) or not (F = 8.516, p < .0001). WSA scores were strongly correlated with SOC content whether corrected for clay content (SOCadjR2 = .571, p < .0001) or not (SOCunadjR2 = 0.490, p = .002). Time since tillage controlled SOC stocks and WSA scores, accounting for 75.5% and 51.3% of the total variation, respectively. We conclude that (1) SOC can be reliably measured in farmed soils using accepted protocols and related to land management and (2) WSA scores can be rapidly measured in clay soils and related to SOC stocks and soil management.

中文翻译：

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农场管理对水中表土有机碳和聚集体稳定性的影响：来自英国西南部的案例研究

很少有可靠的数据集可以激发决策者对可以在农场测量土壤有机碳 (SOC) 的信心。我们与英格兰西南部 Tamar Valley 地区的农民合作，在相似的条件（土壤类型、坡向和坡度）和管理类型下选择采样点。表土（2-15 厘米）于 2015 年秋季采样，土壤有机质百分比 (%SOM) 由烧失量确定并用于计算 %SOC。我们还使用冷水 (WSA) 中宏观聚集体的稳定性（“土壤消解”）作为“土壤健康”的衡量标准，并研究了其与富含粘土的土壤中 SOC 的关系。按林地 (11.1%) = 永久牧场 (9.5%) > 耕地轮作 (7.7%) = 可耕地 (7.3%) 的顺序，管理类型之间的 %SOM 存在显着差异。这直接与永久牧场和林地下的 SOC 储量有关，与可耕地或可耕地轮作相比，无论是否校正粘土含量 (F = 8.500, p < .0001) (F = 8.516，p < .0001）。WSA 分数与 SOC 含量密切相关，无论是否校正粘土含量 (SOCadjR2 = .571, p < .0001) 或不校正 (SOCunadjR2 = 0.490, p = .002)。耕作时间控制 SOC 储量和 WSA 分数，分别占总变异的 75.5% 和 51.3%。我们得出结论：(1) 可以使用公认的协议可靠地测量耕作土壤中的 SOC 并与土地管理相关；(2) WSA 分数可以在粘土中快速测量，并与 SOC 储量和土壤管理相关。