Marketable yield of onion under different irrigation depths, with and without mulch

ABSTRACT The objectives of this study were to obtain the onion crop coefficients and evaluate the influence of different irrigation depths (0, 22, 45, 75 and 100% of crop evapotranspiration) on marketable yield and quality of onion bulbs cultivated with and without mulch of elephant grass. The experiment was carried out in Seropédica, RJ, Brazil, from May to September 2012, in a Red Yellow Argisol. The experimental design was in randomized blocks in split plots, with 10 treatments and seven replicates. Irrigation management was performed through soil water balance using the Time Domain Reflectometry technique, with probes installed horizontally at 7.5 and 22.5 cm depths. The use of mulch allowed the application of smaller irrigation depths, leading to lower crop coefficient (18% in stage II and 3% in stage III) in comparison to the crop without mulch. Irrigation depths associated with the use of mulch influenced the evaluated production variables, proving to be an alternative to increase marketable yield and quality of onion bulbs, with lower irrigation depth.