MORPHOLOGICAL AND STRUCTURAL CHARACTERISTICS OF BRACHIARIA DECUMBENS STAPF. SUBMITTED TO DIFFERENT NITROGEN DOSES AND WATER VOLUMES

Abstract

The present work was developed with the purpose of assessing productive and nutritional aspects of the forage Brachiaria decumbens Stapf related to nitrogen and water, in controlled conditions, by observing the production of dry matter from the shoot and root parts, tillering, leaf area and the estimative of chlorophyll content. The experiment was carried out in a greenhouse, by means of the completely randomized design in factorial scheme 2 x 4 with four replications, from which two water volumes (V1 = 80% of the estimated field capacity, and V2 40% of the estimated field capacity, at about every 3 days) and 4 nitrogen doses (0, 100, 200 and 300 kg.ha-1) in the form of urea, which corresponded to 0, 0.9, 1.8 and 2.7 g/pot, parceled in three times. Water volumes corresponded to 402 and 201 mL/day/pot. During the experimental period assessments of chlorophyll content was carried out by means of Chlorophyll Meter SPAD-502. The first cutting of plants occurred 29 days after the leveling cut, the second cutting 28 days after the first one and the third cut 28 days after the second one. The results evidenced that the morphogenic and structural characteristics, and the production of dried material from the aerial part and roots of B. decumbens are positively influenced by nitrogen fertilization and higher water volume in controlled conditions, thus determining the water requirement for nitrogen availability and assimilation. Key-words: fertilizer, morphogenesis, irrigation, tillering.