Application of two mathematical methods for optimizing the macrocation proportions of hydroponically-grown tomatoes.

摘要

The optimum cationic proportions to maximize crop performance can be determined by fitting statistical models to experimental data. We evaluated and compared Systematic Variations (SV), and Mixture theory (MT) models describing the plant biomass, total yield, and total soluble solids (TSS) of tomatoes (Lycopersicon esculentum Mill.) using six nutrient solutions having different proportions of macrocations (K, Ca, and Mg) during the 2006 growing season. The highest total plant biomass and yield was observed in the nutrient solution containing a high proportion of Ca (TCa) and KCa (TKCa). An opposite trend to the total biomass and yield was observed for the TSS contents with the highest values recorded for the TK treatment. Both the SV and MT models fitted to plant biomass, total yield, and TSS contents of greenhouse tomato explained a high fraction of variation, R2, ranging from 0.96 to 0.98. Based on regression parameters, it was concluded that both the SV and MT models can be used to predict plant biomass, total yield, and TSS contents of greenhouse tomatoes where the growing conditions are similar. However, the use of the SV approach to calibrate models for describing the variation of a plant parameter (e.g. biomass, total yield) to nutrient proportions may be preferred because it requires half the treatments compared to the MT model.