A simple model of potato growth and yield: Part II. Validation and external sensitivity

Abstract

A model has been developed which calculates the dates of 50% emergence and of canopy closure in the potato crop and which estimates total dry matter production and yield. The output from the model has been tested against three sets of independent data, one to test the estimation of dates of emergence and canopy closure, a second to examine the sequence of dry matter accumulation and the third to test estimates of total yield. This validation exercise has shown the model to be successful in its aims of providing an estimate of potential yield of a potato crop using only simple inputs and of describing the development of the crop towards that yield. The limitations of the model have been identified and possible developments have been discussed. The sensitivity of the potential yield to changes in times of planting and harvest and to a range of real combinations of weather has been examined to show the possible consequences of altered farm practice and the year-to-year fluctuations in temperature and radiation receipt. The use of the model in the analysis of shortfalls in farm yields has been discussed.