Hedgerow Soil Carbon to 1 meter (California)

Using a regional survey on intensively managed farms, soil organic carbon (SOC) concentrations and stocks (0–100 cm) were evaluated in a pairwise comparison of long-term (10+ years) woody hedgerow plantings and adjacent crop fields in Yolo County, CA, USA. Twenty-one paired sites were selected to represent four soil types (Yolo silt loam, Brentwood clay loam, Capay silty clay, and Corning loam), with textures ranging from 16% to 51% clay. We hypothesized that SOC will be greater under hedgerows than cultivated fields, in both the surface and the subsurface, but that the difference and distribution will vary by soil type and/or silt and clay content. Soil C was higher in the upper 100 cm under hedgerows (14.4 kg m−2) relative to cultivated fields (10.6 kg m−2) and at all depths (0–10, 10–20, 20–50, 50–75, and 75–100 cm). The difference in SOC (3.8 kg m−2) did not vary by soil type, suggesting a broad potential for hedgerows to increase SOC stocks. Assuming adoption rates of 50 to 80% across California for hypothetical field edges of average-size farms, and an identical SOC sequestration potential across soil types, hedgerows could sequester 10.8 to 17.3 MMT CO2e, or 7 to 12% of California’s annual greenhouse gas reduction goals. Data includes soil physicochemical properties (i.e. carbon, nitrogen bulk density, % sand, % clay, and pH), morphological characteristics (i.e. topsoil depth, rooting depth), and site/management information (i.e. hedgerow age, compost application, cover crop).本研究依托美国加利福尼亚州约洛县（Yolo County）的集约化经营农场区域调查，针对长期（10年以上）木本绿篱种植区与相邻农田开展配对对比分析，测定了0–100 cm土层的土壤有机碳（soil organic carbon, SOC）浓度与储量。共选取21组配对样地，涵盖4种土壤类型——约洛粉砂壤土（Yolo silt loam）、布伦特伍德黏壤质土（Brentwood clay loam）、卡佩伊粉砂黏土（Capay silty clay）与科宁壤土（Corning loam），土壤黏粒含量介于16%至51%之间。本研究提出如下假设：相较于农田，木本绿篱下的表层与亚表层土壤有机碳含量均更高，但二者的差异及碳的分布特征会因土壤类型、粉粒与黏粒含量而异。测定结果显示，绿篱区0–100 cm土层总土壤有机碳储量为14.4 kg m⁻²，显著高于农田区的10.6 kg m⁻²；且在各分层（0–10 cm、10–20 cm、20–50 cm、50–75 cm及75–100 cm）中，绿篱区土壤有机碳含量均高于农田区。两组样地的土壤有机碳储量差值（3.8 kg m⁻²）未因土壤类型产生显著差异，表明木本绿篱提升土壤有机碳储量的潜力具有广泛适用性。假设在加利福尼亚州范围内，中型农场田埂的绿篱种植覆盖率达到50%至80%，且不同土壤类型的固碳潜力一致，则木本绿篱可固存10.8至17.3百万吨二氧化碳当量（CO₂e），占加利福尼亚州年度温室气体减排目标的7%至12%。本数据集涵盖土壤理化性质指标（包括碳、氮含量、容重、砂粒占比、黏粒占比及pH值）、土壤形态特征指标（包括表土层厚度、根系深度）以及样地与管理信息（包括绿篱种植年限、堆肥施用情况、覆盖作物种植情况）。