Irrigation depths and yield response factor in zucchini cultivation

Abstract

ABSTRACT The objective of this study was to evaluate the effect of different irrigation depths on productive performance and yield response of zucchini (Cucurbita pepo L.). A field trial was carried out in the experimental area of the Meteorological Station of the Federal University of Ceará, CE, Brazil. The experimental design was randomized blocks, with six treatments and four replicates. The treatments adopted were: 30, 60, 90, 120, 150 and 180% of the reference evapotranspiration (ETo), estimated by Penman-Monteith (EToPM) and applied by drip irrigation. Fruit weight, number of fruits, fruit length, fruit diameter, pulp thickness, soluble solids and yield were analyzed, as well as water use efficiency (WUE). The methodology proposed by FAO Bulletin 33 was used to calculate the yield response factor (Ky). The 567 mm irrigation depth equivalent to 159% EToPM led to the maximum total crop yield estimated at 24,808 kg ha-1. Highest WUE (64 kg mm-1) was found for the total irrigation depth of 186 mm (30% ETo). Ky values indicated that the crop could be considered as little sensitive (Ky < 1) to water deficit (50, 60, 70, 80 and 90% of the optimal water depth), tending to be proportionally sensitive (Ky = 1) to more severe water deficits (30, 60 and 90% EToPM).