Potential for future growth in lamb supply from sheep and beef farming systems in Hawke's Bay, New Zealand

The potential for expanding irrigation on the Ruataniwha Plains (Hawke's Bay, New Zealand) through proposed in-river water storage creates new land use options, including lamb finishing. It has been estimated that 500,000 additional lambs could be finished each year from 10,000 of the 20,000+ ha within the proposed irrigation scheme. Sheep and beef farming is the predominant land use, covering 785,000 ha or 60% of the Hawke's Bay Region, which has a predominantly summer-dry environment. The majority of sheep and beef farms are found in hill and steep-land, landscapes some vulnerable to landslides and associated soil erosion and sediment loss during rain storm events. There are calls to transition land use on the most vulnerable land to landslides to protective woody vegetation, including production forestry or space planted trees. Using a novel approach of linking spatial land resource information to regional economic data, we modelled lamb production under scenarios of land use change, hierarchically at farm and regional scales. Our results suggest that increases in lamb production on the high-production capability land on-farm, achievable through increases in efficiency and intensification, would offset reductions in production due to tree planting. Further, the additional store lamb demand for finishing created by the proposed water storage project, through the development of 10,000 ha of intensive lamb finishing, could be met by ongoing productivity gains from sheep and beef operations in hill land. Our spatially linked approach to analysis contrasts against a status-quo of regional-scale averages. This offers industry and policy-makers greater confidence in appraising investment options and policy options for managing land use and land use change, respectively.