Fine-scale spatial modelling of pasture production and fertiliser responses under variable climate: assessing a decision support tool in pasture management.

A decision support tool which integrated a geographic information system (GIS) with decision tree models to predict pasture production and pasture responses to phosphate (P) and nitrogen (N) fertiliser was assessed on two farms with contrasting climate in New Zealand. Scenarios of rainfall variability and different fertiliser application strategies were also analysed in this assessment. The results indicated that the models performed well in generating reliable predictions of pasture production and fertiliser responses. The integration of the decision tree models with the GIS provides an efficient tool to assess feed availability and to optimise fertiliser application strategies over landscapes at fine (paddock) scale with considerations of climate variability and environmental impact. The limitations of this decision support tool and possible improvements are also discussed. [ABSTRACT FROM AUTHOR]