Resumen

RINCON, ÁLVARO; FLOREZ, HERNANDO; BALLESTEROS, HUGO  y  LEON, LEANDRO M.. Effects offertilization of Brachiaria humidicola cv. Llanero on pasture productivity in the foothills region of the Llanos Orientales, Colombia. Trop. Grassl.-Forrajes Trop. [online]. 2018, vol.6, n.3, pp.158-168. ISSN 2346-3775.  https://doi.org/10.17138/tgft(6)158-168.

In the foothills region of the Llanos Orientales, Colombia the effects of 3 fertilizer treatments, based on regionally available fertilizers: T1 - no fertilizer (control); T2 - basic fertilizer (kg/ha: P 20, Ca 18, Mg 20, K 18, S 31 and N 18); and T3 - basic fertilizer + additional urea (kg/ha: P 20, Ca 18, Mg 20, K 18, S 31 and N 110), were studied on a non-degraded Brachiaria humidicola cv. Llanero pasture located on an acid, infertile Oxisol that had received biannual maintenance fertilizer for 15 years. Each treatment was composed of 4 paddocks of 0.8 ha each, which were rotationally grazed (7 days grazing and 21 days rest) by a group of Brahman Cebu bulls. Forage production during the rest periods was higher in T3 in both the rainy and dry seasons (1,540 and 940 kg DM/ha, respectively) than in T2 (979 and 665 kg DM/ha) and T1 (958 and 613 kg MS/ha). In T3 also CP concentration in rainy season forage was higher (9.9%) than in T2 and T1 (8.4 and 8.1%, respectively). After a total of 250 days of grazing during the rainy (173 days) and dry seasons (77 days), liveweight production was 317, 599 and 870 kg/ha for T1, T2 and T3, respectively, with stocking rates of 2.2, 3.0 and 3.8 animal units/ha (1 AU = 400 kg live weight) in the rainy and 1.6, 2.1 and 3.2 AU/ha in the dry season, respectively. Daily liveweight gains were, in the same order, 589, 782 and 878 g/animal/day in the rainy season and 379, 642 and 721 g/an/day in the dry season. In economic terms, T3 (basic fertilizer plus urea) represented an additional net income of $US 658/ha in comparison with the control treatment and $US 349/ha in comparison with T2. While the study provides evidence that fertilizing of pasture, particularly with N, has potential to contribute to intensification of livestock production in the region, long-term experiments are required to confirm the sustainability of such systems.

Palabras clave : Forage production; liveweight gains; nitrogen; nutritive value; profitability; stocking rate.

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