Quantification and comparison of shelterbelt carbon stocks within and between an organic mixed-cropping farm and a conventional dairy farm

Abstract

Although woody ecosystems provide a key carbon sink to compensate for current and future greenhouse gas emissions, the potential utility of such sinks within agroecosystems has not yet been fully investigated. We quantified shelterbelt carbon variability, within above- and below-ground pools, for two contrasting farms: a conventional dairy farm and an organic mixed-cropping farm. Shelterbelts comprised deciduous, evergreen and mixed-native species occurring on silt loams, as well as adjacent paddock soils for comparison. Considering all above- and below-ground components, woody shelterbelts contained up to fifteen times more carbon (>600 t C ha-1) than sampled paddock soils (c. 45 t C ha-1). Carbon quantities within organic farm shelterbelt soils were 2.5 times higher than dairy farm soils, suggesting a potential land use effect. Soil carbon comprised about 10 % of total ecosystem carbon within shelterbelts. This study indicates that farm shelterbelts can serve a role as relevant carbon sinks within New Zealand agroecosystems.