A tailor-made crop growth model for the tomato production systems in Colombia

Potential crop models simulate the plant growth under nonlimiting biophysical conditions with no other factor than the climate to which the plants are exposed to. These models may fail to adequately represent the crop performance if they are not adapted to the local conditions. The particularities of Colombian tomato systems (greenhouse and open field) demand the recalibration of existing models to make a more realistic representation of those systems. Therefore, a locally calibrated crop model was proposed considering both production systems. To this purpose, four on-farm calibration experiments were carried out, two under greenhouse conditions with average temperatures of 17.4 and 17.9ºC in Santa Sofía (Boyacá) and two under open field conditions in Páramo and San Gil (Santander), with average temperatures of 20.6 and 24.0ºC, respectively. The crops were commercially managed according to the local practices. Plant data was collected through destructive measurements carried out on a fortnightly basis, while climate data were collected for the entire crop growth cycle. Independent calibration of the dry matter fractions allocated at the plant organs in function of thermal time resulted in an acceptable model performance. The calibration of the model under commercial conditions gave a better representation of the local systems but at the expense of accuracy since on-farm experiments cannot be controlled as those performed in research facilities