Hedgerows on Crop Field Edges Increase Soil Carbon to a Depth of 1 meter

Abstract

Effective incentivization of soil carbon (C) storage as a climate mitigation strategy necessitates an improved understanding of management impacts on working farms. 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. 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.

Influence of soil properties and land use on organic carbon storage in agricultural soils near hedges

“…By 3 m from the hedge, there were no significant differences in SOC stocks compared to baseline SOC stocks at 10 m. The influence of the hedge on SOC stock in adjacent agricultural fields was thus only seen very close to the hedge. Similar results were found in the literature for a temperate climate in Europe, with an increase in SOC stocks with hedges on the margin of agricultural fields (Pardon et al, 2017;Viaud & Kunnemann, 2021) or for other climates (Chiartas et al, 2022), but with high variability depending on site characteristics (Drexler et al, 2021). Similar to results of this study, Ford et al (2019) report an increase in SOC stocks with the establishment of hedges in grasslands, and an influence of the hedge on SOC storage up to 2.2-3.4 m from the hedge.…”

“…Most of the baseline parameters corresponds to 0–15 cm measurements; it is therefore not surprising that the models explain Δ S 30 with more accuracy. It was noteworthy that hedge characteristics did not influence Δ S tot , as hedges can increase deep release of C in soils through roots (Chiartas et al, 2022). It is important to note, however, that the species diversity of hedges was not considered in the model.…”

Carbon storage in old hedgerows: The importance of below‐ground biomass

“…However, these calculations were based on limited empirical data on hedgerow C stocks. Recent empirical studies have focused on SOC storage and sequestration of hedgerows (e. g. Biffi et al., 2022; Chiartas et al., 2022; Van Den Berge, Vangansbeke, Baeten, Vanneste, et al., 2021; Viaud & Kunnemann, 2021), despite more than 80% of the additional C stocks of hedgerows, compared with cropland, being found in the biomass (Drexler et al., 2021). Empirical data on hedgerow biomass, particularly data on below‐ground biomass (BGB), remain limited because sampling is labour‐intensive and time‐consuming.…”

Native blue elderberry in hedgerows bridges revenue and conservation goals

“…hedgerows to adjacent cash crops (Morandin et al 2016), this study goes further in exploring the capacity for native plant hedgerows themselves to provide a viable cash crop while still being managed for ecosystem services, such as pest management, pollination and carbon sequestration benefits (Chiartas et al 2022). This study worked with farmers to try different planting designs for elderberrycontaining hedgerows, assess establishment and maintenance costs, measure potential berry yields and revenue in the first few years after planting, estimate future revenue at maturity, and assess market demand for California-grown elderberry.…”