Land use pressure, soil quality and links with land value

Pressures associated with agricultural land intensification can be a precursor to changes in soil quality measurements. These pressures include more intensive land use, nutrient application, and increased livestock numbers, or density. A unique indicator associated with land use pressure is agricultural land value. Because land value is assessed at a property scale and regularly updated in New Zealand, we hypothesized land value to be a good proxy for agricultural intensification. We tested whether a relationship exists between land value per hectare, point-scale soil quality, land pressure indicators, and catchment characteristics, as this has not been tested previously. Soil quality from a national soil quality monitoring dataset, dominant land use in catchments, land pressure indicators e.g. stock units, and catchment characteristics (elevation, rainfall etc), across 192 catchments in New Zealand were used in the analysis. An array of models was tested with the random forest model exhibiting the best goodness-of-fit measures. We will present the most important explanatory variables in predicting land value per hectare for the catchment characteristics, land pressures, and soil quality indicators. We conclude that that land value per hectare has a well-defined relationship with land use and some soil quality measures, though expressing soil quality data at a catchment scale presented some challenges.