Modelling tomato crop growth and development in relation to nitrogen fertilization under high altitude cold tropical conditions

Nowadays, crop models are a widespread tool for both research and production activities. However, most of the models were developed and calibrated for potential conditions at places where there is a narrow gap between potential and actual yields. The objective of this work was to incorporate the effect of nitrogen (N) supply in a tomato crop growth model calibrated for high altitude tropical conditions. We carried out field experiments to determine the effect of N fertilization on plant parameters such as leaf area (LA) and allocation of dry matter (DM) in fruits. A total of 10 treatments ranging from 196 to 1114 N kg ha-1 were evaluated, six of them were used in the model calibration and the remaining four were reserved for validation. Plant development was determined by means of accumulated thermal time (ATT) using a base temperature of 10°C. LA results were fitted with a nonparametric model to predict the changes in LA as response to N supply. This N-model was introduced as a module within the tomato model. The N-module calculates LA for a given amount of soil N available and ATT. Simultaneously, a nitrogen stress factor (NSF) was calculated as the ratio between daily available soil N per plant and N demand to reach the potential growth. If NSF is less than one, a leaf area reduction factor (LARF) was calculated as the ratio among LA estimated by the nonparametric model and that calculated by the potential model. In this way, a deficient N-supply affects plant growth by correcting the leaf DM produced at the end of each day by LARF. The performance of the model was satisfactory as shown by statistics such as the root mean square error, model efficiency and coefficient of determination.cited By 0 document_type: Conference Paper source: Scopusstatus: publishe