Exploring limits and trade-offs of irrigation and agricultural intensification in the Ruamahanga catchment, New Zealand

Abstract

ABSTRACTIrrigation schemes enable agricultural intensification or change to more profitable land uses, but may also lead to adverse environmental effects (e.g. nitrate leaching). Decision-makers face the challenge of assessing potential intensification options and comparing their advantages and disadvantages. We used the Land-Use Management Support System (LUMASS) to assess land-use development scenarios for the potential irrigable areas Black Creek and White Rock in the Ruamahanga catchment. Our results show that intensification and expansion of dairy farming and arable cropping increased production levels, but also nitrate leaching and greenhouse gas emissions. A higher production increase was associated with a higher environmental footprint. However, increasing the number of land-use conversion options reduced the environmental footprint while achieving the same agricultural production. Optimizing the match of land use and the landscape’s potential to provide ecosystem services increased the operating surplus while maintaining the environmental footprint. The presented modelling approach can provide decision-makers with evidence-based guidance for spatial planning and policy development on agricultural and environmental limits of land-use development.