Simple models of carbon and nitrogen cycling in New Zealand hill country pastures: exploring impacts of intensification on soil C and N pools
Concerns about climate change and water quality make it necessary to have a better understanding of the cycling of carbon (C) and nitrogen (N) within landscapes. In New Zealand, pastoral farming on hill country is a major land use, and there is little information available at a landscape level on the cycling of C and N within these systems, particularly the impacts of land use intensification. Published information on the individual components of C and N cycles in hill country pastoral systems was used to construct simple C and N models for two notional hill country paddocks with contrasting amounts of annual net herbage accumulation (NHA). These simple models of C and N cycling were used to explore the potential impacts of intensification on soil C and N pools. The C and N models constructed illustrate that both the C and N cycles in hill country pastoral farming are characterised by large fluxes in and out of the system and relatively small annual accumulations or depletions of their respective soil poo...