Abstract
Water management for irrigation can be defined as a strategy of planning and support systems to save and optimize water resources for human and environmental purposes. Regulated deficit irrigation (RDI) or soil water deficit is a strategy where the amount of water used is kept below the maximum level, and the minor stress that develops has minimal effects on yield. In this irrigation model, the entire root zone is irrigated at less than the maximum crop evapotranspiration, in different phenological phases, without interfering significantly in the physiological behavior of crops. This allows a quantitative and qualitative increase in different crops, and water use efficiency in the agriculture. The present study aimed to identify the effect of regulated deficit irrigation on the qualitative standards of tomato cultivar N-901 for industrialization purposes. Deficit irrigation was carried out during the vegetative growth stage, considering different seedling transplanting periods. The experiment was conducted in a greenhouse at the School of Agronomy of the Federal University of Goias (UFG). The experimental design was a randomized complete block with five replicates, in a 2 x 4 factorial arrangement. The plots were made by combining two periods of irrigation deficit (10 and 20 days after transplanting - DAT) and four soil water tension thresholds (30; 40; 60; and 70 kPa). The results showed that the studied cultivar responded significantly to the soil (substrate) water tension, providing different agronomic development profiles. Water deficit was shown to reduce the total volume of water applied during the cycle, increasing the concentration of soluble solids in the fruits and maintaining titratable acidity in the standards of processing industries, in addition to increasing pulp yield when compared to processing industries. The tensions of 60 and 70 kPa applied at 10 DAT were the ones that most intensified the soluble solids content without significantly affecting the agronomic development of the crop.
Keywords: water productivity, deficit irrigation, pulp yield, soluble solids.
