Adaptation of the CROPGRO model to simulate the growth of field-grown tomato

Modelling the growth of field-grown tomato (Lycopersicon esculentum Mill.) should assist growers and extension workers throughout the world to outline optimal crop management strategies for specific locations and production systems. In previous use of a greenhouse tomato model (TOMGRO), effects of nutrient and water stress on the growth of field-grown tomato were not accounted for, and it was decided to modify a more generic growth model (CROPGRO) that does address these issues. It proved feasible to capture growth and production features typical of field-grown tomato by modifying existing parameter files previously used for peanut (Arachis hypogaea L.), without changing the FORTRAN code or model structtire. Parameter estimation and model calibration involved use of data sets for three seasons of field-grown tomato at the Gulf Coast Research and Education Centre (GCREC) in Bradenton, Florida, USA. Photosynthetic parameters were calculated by comparison to the TOMGRO model. Some of the more important parameter modifications, and their implications with respect to modelling results, are presented. Results from these initial modifications using the CROPGRO generic crop model show both the versatility and the robustness of the model. The general procedure presented here may also be employed as a ‘blueprint’ for future CROPGRO adaptation to other vegetable crops.