IMPACTS OF WATER STRESS ON Urochloa brizantha FORAGE CULTIVARS

Abstract

Water deficit during the dry season is one of the main factors affecting the productivity and quality of pastures. The present work aims at evaluating the effects of water deficit on the morphological and productive characteristics of Urochloa brizantha cultivars grown in Quartzarenic Neosol. The experiment was conducted in a greenhouse under a completely randomized design with a 4×2 factorial arrangement, with four cultivars (Marandu, MG4, MG13 Braúna and MG5 Vitória), two water availability conditions (50% or 100% of field capacity) and six repetitions. Structural, morphogenic and productive variables were evaluated 15, 25 and 35 days after the beginning of treatment application. For all productive characteristics evaluated during 35 days of water stress, it was observed that a 50% reduction in water availability significantly (P<0.05) reduced total fresh and dry mass production and leaf production of Marandu, MG13 Braúna and MG5 Vitória. Except for MG13 Braúna, the leaf/stem ratio of these cultivars was impaired. Regardless of water availability, when comparing forages during 35 days, lower cumulative leaf length and higher fresh and dry mass production of stems were observed in the Marandu cultivar. Regarding the response of productive characteristics, the MG4 cultivar showed the best results under water deficit when grown in Quartzarenic Neosol.