Articles
A WEATHER-DRIVEN MODEL OF POTENTIAL YIELD IN POTATO AND ITS COMPARISON WITH ACHIEVED YIELDS
It was validated by MacKerron (1985). The phases of crop growth used by that model and its driving variables are described briefly.
Important features of the model for agronomic application are that the growth phases are easily recognisable and that the value calculated for "potential" yield is unique to an individual crop, given its dates of planting and haulm destruction and the weather experienced.
The calculations made using this model can be compared with achieved performance to suggest causes of departure from potential.
As the effects of constraints on yield are quantified, the model is being developed to estimate actual yields.
Comparisons are shown between calculated potential yields and achieved yields in each of three types of crop: a) grown for maximum yield, b) droughted, c) good commercial.
Examples are given of how the model can be used to quantify any supposed benefits from, or need for, changes in farm management.
Applications of the model to the estimation of current yield, and to forecast yield both by a predetermined date and by a moving future date, are discussed with particular reference to the differing kinds of meteorological input required for each of these applications.