Data for model operation, calibration, and evaluation

Abstract

The International Benchmark Sites Network for Agrotechnology Transfer (IBSNAT) Project has recognized that the application of models depends not only on the availability of models and application software, but also on the availability of data that facilitate model calibration, evaluation and application. IBSNAT, therefore, has devoted considerable attention to developing and clarifying procedures that relate to data acquisition, storage, exchange, and use. For model operation, IBSNAT has emphasized the need for a balanced set of information that includes information on the site where the experiment was conducted, on the weather during the growing cycle, on the characteristics of the soil at the start of the growing cycle, on the management of the crop, and on new cultivar traits. For each of these, IBSNAT has defined a minimum amount of data that is necessary for model operation. This minimum amount of information has been termed a ‘Minimum Data Set’, a phrase that is applicable to data sets for model operation as well as calibration and evaluation. For the latter, data on the date of occurrence of the main phenological events, on yield and its components, and on biomass at final harvest are necessary as a minimum addition to the data for model operation. Within-season measurements of some growth characteristics may also be necessary for calibrating models for new situations. Information from such studies is easily lost unless specific steps are taken to ensure that it is conserved. To facilitate both conservation and use, IBSNAT has developed some simple, standard experiment documentation files that can be established and edited easily, and that can also be transferred directly among workers without the need for ‘retrieval’ from a central database. The widespread use of the data structures developed by IBSNAT would make possible a ‘dispersed’ but nonetheless standard database for model calibration and evaluation, as well as documentation of experiments.