Estimating the carbon sequestration potential of agricultural soil reforested with directly seeded native vegetation belts around Canberra, Southern Tablelands, NSW

Sowing native vegetation tree belts on agricultural soils using direct seeding is a technique that has been carried out by Greening Australia in the Australian Capital region for many years. It results in improved landscape biodiversity and habitat, provides shelter for pastures, crops and livestock and protects soil from erosion. Initial research identified a range of changes the vegetation belts make to the physical and chemical functions of soils including: an increase in the thickness of the surface litter and depth of the A o horizon. This leads to a commensurate increase in total soil organic C; a reduction in bulk density; an increase in total nitrogen; and a decrease in pH and effective CEC. The study also used the Landscape Function Analysis method and found a significant improvement in the three functional indices: infiltration, nutrient cycling and stability. These findings are being investigated as part of a new study which aims to develop a model to estimate the C sequestration potential of agricultural soils in which vegetation belts have been established. Additionally, the chemical nature of the soil organic C in the vegetation belts will be compared with C from adjacent grassland soils to identify whether the trees are sequestering a more stable form of soil C than the grasslands. The soil biological and ecological characteristics are being analysed as part of the research.