Soil quality evaluation and the interaction with land use and soil order in Tasmania, Australia

Soil quality information has been collected at 272 sites across Tasmania. Soil target values were developed for six key soil quality indicators, with values dependent on soil order and land use. The selected indicators were pH (H2O), organic carbon, extractable phosphorus, exchangeable sodium percent, bulk density and aggregate stability. Soil quality monitoring sites were biased to agricultural land uses, which was justified due to these land uses being more likely to result in soil degradation than conservation or native forestry. Cropping and perennial horticulture land uses had a greater proportion of sites outside targets for organic carbon and bulk density than grazing pasture and forestry. Most intensively used soils were within pH targets. Aggregate stabilities at many sites were outside targets under cropping and irrigated pasture indicating that cropping sites had an increased risk of erosion. Extractable phosphorus levels were below target for most dryland pasture sites and above target for most irrigated pasture sites. Soil order explained more variability in organic carbon, aggregate stability, bulk density and ESP than land use but land use explained more of the variability in pH and Olsen P than soil order.