Produção e qualidade de melão rendilhado submetido a diferentes tensões de água no solo e adubação potássica no nordeste paraense

Abstract

Amid the high productive demand for lacy melons, little is known about the water and nutritional needs of this crop, considering the edaphoclimatic particularities of the northern region. This work aimed to evaluate the behavior of the lacy melon, in a protected environment, submitted to different water tensions in the soil and doses of potassium applied via fertigation, northeast paraense. The experiment was conducted between May and August 2019 at the Igarapé-açu school farm (FEIGA, UFRA), located in the municipality of Igarapé-açu - PA. The soil at the cultivation site consists of a Dystrophic Yellow Argisol with a medium sandy texture. The experimental design adopted was randomized blocks (DBC), in a 4 x 5 factorial scheme, with 20 treatments and three replications, totaling 60 experimental plots, consisting of five percentage doses of potassium (0, 50, 100, 150 and 200%) of the recommended dose for culture and four water tensions in the soil (15, 30, 45 and 60 kPa) used as an indication of the moment to irrigate the critical tension. The variables analyzed were: average fruit mass (kg), average productivity (t ha-1) transverse and longitudinal diameter of the fruits (mm), pulp thickness (mm), ° Brix (%) and pH. The variables average fruit mass, average productivity and longitudinal diameter of the fruits had an isolated effect. Analyzing the effect of water stress on the soil under the average fruit mass, average productivity and longitudinal diameter, better results were observed when irrigation was carried out at 15 kPa tension, with 1.54 kg of fruit, 51.24 t ha-1 and 127.7 mm, respectively. For treatments with potassium doses, a significant quadratic effect was observed in the average fruit mass, average productivity and longitudinal diameter, with better results in the potassium dose 255.11 kg ha-1 of K2O for average mass (1.70 kg) and average productivity (55.17 t ha-1) of the fruits and for longitudinal diameter at the dose of 232.82 kg ha-1 of the recommended with 127.50 mm. There was a significant effect for the interactions of potassium dose and water tension in the soil (K x T), for pulp thickness (EP) with better results in the combination of potassium dose of 123.84 kg ha-1 of K2O (K50%) and tension of 38.5 kPa, applying this level of nutrient and water, obtained a high thickness of the pulp with an economical dose, ° Brix obtaining a better index (9.5%) in the dose 247.68 kg ha-1 of K2O and 371.52 kg ha-1 of K2O with a tension of 24.67 kPa, with no difference between them and the transversal diameter of the fruits with the best index (128.88 mm), in the combination 43.8 kPa and a dose of 247.68 kg ha-1 of K2O, respectively. The present study shows that irrigation at a tension of 15 kPa and a dose of 247.68 kg ha-1 K2O (100% of the recommended dose) can be indicated for the conditions of the study.