RESPONSE OF Brachiaria decumbens cv. SEÑAL TO THE FRACTIONATED APPLICATIONS OF NITROGEN UNDER THE ENVIRONMENTAL CONDITIONS OF GUALACA, PANAMA. 2001-2003.

Abstract

For a period of three years (2001-2003), it was conducted in the Experimental Station of Gualaca a work with Brachiaria decumbens cv. Señal grass with the objetive of studying the effect of the strategic use of the fractioned of nitrogen on the yield and quality forage in the raining season there were evaluated three levels of fertilization (N) with nitrogen (60, 100 and 140 kg/ha/year) fractioned 1, 2, 5 and 9 times (FN) and corresponding to once (june), twice (june and november), five time (every two cuts) and nine applications (every cuts) of the totd levels of N, respectively. Cuts were made every 21 days. Additionaly, all plots received 30 y 20 kg/ha/year of P₂O₅ and K₂O, respectively. It was used a complete randomized block design with three replications in a split plot arrangement. The main plot was N and the subplot was FN. Yearly there were done nine cuts every 21 days at 15 cm of height. It was found a significant linear effect (P<0.01) among the nitrogen level and the fractionated on the dry matter (DM) yield and are given in the following equations: Y= 155.14 N – 0.61 N²; P<0.01; R²=0.85; y Y=4189 FN – 362 FN²; P<0.01; R²=0.76, respectively. Dry matter yield were 9157, 9133 and 7750 kg/ha for year one, two and three, respectively. Interaction between N and FN was highly significant (P<0.01) and it was observed that level of 50 kg N/ha had Little effect on DM of B. decumbens. It was conclude that due to there was not differences in DM yield of B. decumbens for fractioned nitrogen levels every cut and every two cuts, it is profitable to take the adoption of the last one. Also N levels applie totaly or fractioned did not affect valmes of crude protein, calcium and in vitro digestibility, possibly at 21 days of regrowth.