Fertigation management using the electrical conductivity of a soil solution promote increased yield in watermelon

Watermelon crops demand nutrients and water, which are factors that limit their development. The aim of the experiment was to evaluate watermelon production as a function of the electrical conductivity of the soil solution. The experimental design used in the experiments was a randomized block design with four replications. The first factor included six levels of electrical conductivity of the soil solution (0.6, 1.2, 1.8, 2.4, 3.0 and 3.6 dS m-1), and the second factor included two planting times: E1-autumn and E2-spring. The characteristics evaluated were fruit length (FL) and diameter (FD), fruit mass (FM), fruit pulp pH (FPpH), fruit peel thickness (FPT), soil electrical conductivity (SEC), fruit pulp brix (FPB), titratable acidity (FPA) and the FPB/FPA ratio of the fruit pulp, number of fruits (NF), total productivity (TP) and commercial productivity (CP) of watermelon fruits. The variables FL, FD and FPB/FPA were influenced only by the planting season, with variations of 44%, 16% and 49%, respectively, E2 is better. However, TP and CP were significantly different for both factors. E2 showed the best results for most of the variables and is the most recommended, with increases of more than 400% for TP and 236% for CP. Only SEC, FPpH and FPB significantly affected the interations. The electrical conductivity of the soil solution should be restored to 2.3 dS m-1 to obtain maximum productivity and to 2.6 dS m-1 when the aim is to achieve maximum accumulation of soluble solids in the fruit.