The cropping systems-model PERFECT as a quantitative tool in land evaluation - an example for wheat cropping in the Maranoa area of Queensland

Abstract

The mechanistic cropping systems model PERFECT was validated for six different soils and used as a tool to evalute land suitability of wheat cropping in the Maranoa, a marginal cropping area of Queensland. Using 100 years of historic climate data from the area, and crop, soil and management parameters, simulations provided an objective insight into the key interactions of the cropping system. Current methods of land suitability evaluation are qualitative and rely on the experience of the land resource surveyor and local precedent. Consequently, where local precedent is lacking, as in marginal areas, current methods are considered less reliable and quantiative data from simulation studies will be useful. Using this process, the significance of key components of the systems (climate, plant available water capacity, soil nitrate and soil loss hazard) were quantified. These quantitative data were used to establish critical values for diagnostic attributes for land suitability evaluation in the Maranoa. The role for this approach as a tool in quantitative land evaluation is discussed.