ABSTRACT The objective of this study was to evaluate the effect of different irrigation depths applied by drip system and nitrogen fertilization levels that promote higher yield and water use efficiency in onion (Allium cepa L.). The treatments consisted of five irrigation depths (50; 75; 100; 125; 150% of crop evapotranspiration), applied by drip system, combined with five nitrogen fertilization rates (0, 40, 80, 120 and 160 kg ha−1), in a 5 x 5 factorial scheme, in a randomized block experimental design, with four replicates. Irrigation depths estimated at 120.2% and 77.81% of crop evapotranspiration promoted higher yield and water use efficiency for total yield of onion bulbs, respectively. Nitrogen dose of 160 kg ha−1 promoted maximum total yield and water use efficiency.

ABSTRACT Vegetables intercropping of results in a better use of natural resources, water, light, and nutrients, when properly managed. The objective of this work was to evaluate the performance of lettuce and radish in single crop and intercropping systems under different irrigation water depths. The experiment was conducted in a protected environment at the State University of Maringá, in Maringá, Paraná, Brazil. A randomized block experimental design was used in a 4×2 factorial arrangement, with four replications. The first factor consisted of four irrigation water depths (60%, 80%, 100%, and 120% ETc), and the second factor consisted of two crop systems (single crop and intercrop). A drip irrigation system was used, consisting of constant water table lysimeters. The variables evaluated were: shoot fresh weight, root dry weight, and leaf area for the lettuce crop; total fresh weight, root fresh weight, and root diameter for the radish crop; and yield, water use efficiency, and land use efficiency index for both crops. Shoot fresh weight, leaf area, and yield of lettuce, and total fresh weight, root fresh weight, and yield of radish increased as the irrigation water depth applied was increased. Total fresh weight, root fresh weight, root diameter, and yield of the radish crop were higher in the intercropping system. The water use efficiency of both crops was higher in the single crop, and the land use efficiency index was higher in the intercropping system.