Intensification and diversification of New Zealand agriculture since 1960: An evaluation of current indicators of land use change

Previous studies of New Zealand's environmental and agricultural history have provided a broad-brush characterisation of land use change that potentially misses pivotal fluctuations in land use policy and practice that would inform us of key drivers of ongoing agricultural land use change. Of particular interest to policy makers is the period after the end of agriculture's ‘long boom’ in the late 1970s, when a dramatic change in economic policy occurred and farming subsidies were removed. A review and principal components analysis of 35 New Zealand agricultural statistics from the past 40 years identified two main patterns of change in land use, production, and farm inputs. One set of variables, which explained 49% of the variation, indicates an overarching, strong and steady trend for agricultural intensification and to a lesser extent diversification, as indicated by (a) increasing stocking rates and yields, (b) increased farm fertiliser, pesticide and food stock inputs, (c) conversion to more intensive forms of agriculture, and (d) diversification into forestry and deer farming. A second group of variables, which explained 22% of overall variation, inflects around 1982/1983, the time of a major shift in agri-economic policy that removed farm subsidies. The second group of changes included some contraction in agriculture (especially in sheep farming) and its associated inputs and a decline in rural population. There is evidence of acceleration in intensification and diversification in the past decade and for slowing in the contraction of the second set of variables between 1997 and 2001. The drivers of these changes are poorly understood and their impacts on biodiversity conservation in farmed landscapes cannot be discerned from the national indicators currently being monitored. The accelerating agricultural intensification over the past 40 years raises concern about whether New Zealand farming is broadly ecologically sustainable now, and especially whether it could remain so in future.