Regime de irrigação e densidades de frutos na produção do melão hidropônico

Abstract

One of the factors that influence loss in productivity of melon crop is the inadequate irrigation system. Intervals between irrigations is one importante case determined, especially in hidroponic systens. Two experiments were carried out with melon in hidroponic system Departamento of Fitotecnia of the Universidade Federal de Santa Maria, during spring - summer and summer-autumn seasons. The objectives were: get an estimative of the effect intervals between irrigation in the physiology, electric energy cost, accumulation, dry biomass partition, and fruit yield, with one and two fruits per plant. During spring - summer analyzed the effect between of irrigation intervals in fruits and yield and correlate with meteorologycal elements. During summer autumn were constituted two intervals irrigation at 6 to 19 (T15 15 min of irrigation with intervals of 15 min and T30 15 min of irrigation with intervals of 30 min.), and two fruit densities per plant D1 (one fruit) and D2 (two fruits), except in the second experiment that are constituted only of irrigation treatment. There was no interaction between irrigation intervals and fruit densities during spring - summer. Increasing intervals between irrigations decreases water availability to the plant at the beginning of growth and maturity of the fruits, because of increasing atmospheric demand. However, did not affect the evolution of dry biomass partition, and fruit yield. It compensate one decreasing in power cost in 32,7 %. From one to two fruits per plant increase the allocation of the photo-assimilates in fruits with a decrease in fruit size, however reflected in the growth of the final yield of 44%. An increase from 15 to 30 min between irrigation intervals did not affect fruit growth and the final yield during summer - autumn. Also the thermal time and solar radiation were importants to determine fruit growth due to the high coefficient of determination found in the proposed models (R2 varying from 0.71 to 0.94).