Effects of Regulated Deficit Irrigation (RDI) Applied at Different Growth Stages of Greenhouse Tomato on Yield and Fruit Quality

The agriculture’s consistent request for irrigation water exerts pressure on the availability of water already in crisis. The adaptation of new economic irrigation techniques is a major and urgent goal. In this context, this work aims to estimate and to compare the Regulated Deficit Irrigation (RDI) effects on greenhouse’s tomato crop under three tomato growth stages. The water regimes applied were (i) “FI” Full Irrigation which ensures 100% of water requirements of the culture, (ii) “RDI1-25” and “RDI1-50” consists in giving 75% and 50% respectively of water requirements of the culture applied under “FI” until first truss blossom, (iii) “RDI2-25” and “RDI2-50” consists in giving 75% and 50%, respectively, of water requirements of the culture applied under “FI” from first truss blossom until the first harvest, and (iv) “RDI3-25” and “RDI3-50” consists in giving 75% and 50%, respectively, of water requirements of the culture applied under “FI” during the harvest period. The Soil Water Content (SWC) measures highlighted more comfortable soil moisture under FI compared to RDI treatment. Results also showed that RDI2 saved yield and fruit quality. Indeed, an irrigation amount reduction by 20% under RDI2-50% generated only 3% yield reduction. Although RDI2-50 and RDI3-50 received the same irrigation amount, RDI2-50 regime saved fruit yield and number with an improvement on fruit skin color, firmness, and refractometry index (Brix). RDI-2 proved that the second tomato growth stage was the best period which helps to reach the challenge “more crop per drop.”