Model-based Control of Nutrient Solution Concentration Influences Tomato Growth and Fruit Quality

Summary

Diurnal changes in microclimate in a greenhouse are often greater than changes in daily averages over weeks or months. Thus, one may hypothesize that changing the nutrient solution concentration supplied to plants at intervals less than one day would improve tomato yield and quality. To test this hypothesis research was conducted to compare four nutrient control strategies for their effects on plant growth, fruit yield, fruit quality, and root characteristics of `Counter' tomato [Lycopersicon esculentum (L.) Mill.]. The four strategies were 1) EC variable, adjustment of nutrient solution electrical conductivity (EC) at 15-min intervals according to greenhouse microclimate over the previous 15-min and empirical models of photosynthesis and transpiration; 2) EC daily, daily adjustment of nut