Irrigation strategies and soil conditioning on thermal index and yield of cherry tomato1

Abstract

Tomato cultivation is highly demanding on the supply of water throughout its phenological cycle, especially in regions where rainfall is irregular or scarce. Given the above, the objective of this study was to analyze the viability of thermal index for determining water deficit in cherry tomato under different strategies of controlled deficit irrigation and use of a hydrogel-type soil conditioner. The experimental design adopted was randomized blocks in a 5 × 2 split-plot arrangement, referring to the irrigation strategies (FI-Full irrigation, RD-Regular deficit irrigation, with a continuously applied water deficit, S3-Irrigation with controlled deficit in the vegetative stage, S4-Irrigation with controlled deficit in the flowering and fruiting stages and S5-Irrigation with controlled deficit in the maturation and harvest stages), with water deficit established at 50% of crop evapotranspiration, and use of hydrogel (WiH-With hydrogel, WoH-Without hydrogel), with four replicates, and with three plants per plot. The variables tested were: total number of flowers and fruits, total fruit weight and canopy thermal index. At 60 days after transplanting, the regular deficit irrigation and irrigation with controlled water deficit in the flowering, without hydrogel, showed the highest means of thermal index (0.98, 1.03 and 0.70 °C, respectively) and lowest leaf water potential (-0.70,-0.48 and-0.50 MPa, respectively). The thermal index obtained by thermographic images is viable for determining the effects of water deficit on cherry tomato.