Development, Verification, and Analysis of Simple Mathematical Model of Lettuce Productivity under Different Light Conditions

Abstract

Lettuce is an important agricultural plant which is often cultivated under artificial illumination including light of light emitting diodes (LEDs). Spectrum and intensity of used illumination and duration of photoperiod can strongly influence a final lettuce biomass; their effects can be interacted. It means that search of optimal light conditions is complicated problem for experimental investigations because numerous combinations of light conditions should be analyzed. A mathematical model of lettuce productivity can provide the potential tool for intensification of this search; earlier, we preliminarily proposed the minimal model of lettuce productivity under the LED illumination. The aim of the current work was further development, verification, and analysis of the simple mathematical model of the lettuce productivity. Dry weight of a lettuce leaf rosette was used as the main variable of the model; its changes were described as function of difference between production of biomass through assimilation and its consumption through respiration. The model was quantitively parameterized and verified on basis of our previous experimental works devoted to influence of parameters of the LED illumination on lettuce characteristics. It was shown well correspondence between experimental and simulated results. Further analysis of the developed model predicted optimal illumination conditions of the lettuce cultivation. Particularly, it showed a positive influence of gradual and step increase of the light intensity on final biomass of cultivated lettuce plants. Thus, the developed model can be used as the tool for the theoretical prediction of optimal light conditions for the lettuce cultivation.