Soil water stress ranges: water use efficiency and Chinese cabbage production in protected cultivation

ABSTRACT Water deficit or water excess can affect development and yield of vegetables. The objective of this study was to evaluate the effect of different soil water stress ranges for Chinese cabbage (Brassica pekinensis) in a protected cultivation. The researches were carried out at the Olericulture Sector of Universidade Federal Tecnologica do Paraná between April and July, 2015 and January and April, 2016. Two Chinese cabbage cultivars were analyzed (Eikoo and Kinjitsu) with four soil water stress range (13-17, 23-27, 33-37 and 43-47 kPa) moments of irrigation indicative parameters. The trial design was completely randomized, with four replications, in a factorial scheme. For head fresh mass, a soil stress range of 13-17 kPa resulted in higher yield (527.2 g/plant), in the first research. In the second one, ‘Eikoo’ showed higher productivity in the stress range 13-17 kPa (70.7 t ha-1). About water use efficiency, higher values were obtained, 42.1 kg m-³ in the first research and 47.3 kg m-³ in the second one with Kinjitsu and Eikoo cultivars, respectively, in the stress range 13-17 kPa. ‘Eikoo’ had a higher productivity than ‘Kinjitsu’ in the second research (summer), but in the first one (autumn-winter) these differences were not expressive. The use of stress ranges as indicative of irrigation return time between 13-17 kPa is suitable for Chinese cabbage crop.