ABSTRACT
The objective was to evaluate the effect of three stocking rates (2, 3.9, and 5.8 animal units ha−1) and three fertilization levels (0, 150, and 300 kg N ha−1 yr−1) on herbage mass and nutritive value of elephantgrass (Pennisetum purpureum Schum.) cv. IRI-381. The experiment was conducted from May to August of 2009 and 2010 in Itambé, PE, Brazil, during the rainy season. Treatments were allocated in a split-plot arrangement in a completely randomized block design. The variables measured included leaf mass (pre- and post-grazing), botanical composition, soil cover, leaf area index, light interception, leaf angle, and concentrations of dry matter, organic matter, N, and in vitro digestible dry matter. When fertilized with 300 kg N ha−1 yr−1, leaf mass reached 18,560 kg ha−1. Leaf area index decreased with increasing stocking rate. The relationship between sward height and light interception was R2 = 0.0126. Increased stocking rate resulted in greater contribution of signalgrass [Brachiaria decumbens (Stapf.) R.D. Webster] in the botanical composition, with a contribution up to 29% in 2010. Elephantgrass nutritive value is directly affected by the fertilization levels and stocking rate, with highest nutrient concentrations observed with 2 AU ha−1 and 300 kg N ha−1 yr−1.(AU)
Subject(s)
Animals , Pennisetum/physiology , Fertilizers/analysis , Animal Feed/analysis , Brazil , Pasture , Nutritive ValueABSTRACT
The objective of this research was to select elephantgrass clones for grazing conditions. A randomized complete block design was used, with 16 treatments and four replications. Each plot had a total area of 25m2, with the presence of animals. The following parameters were determined: leaf blade accumulation rate (LBAR) above 40cm height and total, stem accumulation rate (SAR), total forage accumulation rate (TFAR), dry matter concentration (%DM), crude protein concentration (%CP) and, neutral detergent fiber (%NDF). The results showed significant difference (P<0.05) between clones and evaluation periods for LBAR above 40cm, total LBAR and TFAR, with mean values of 28.08, 41.62 and 49.18kg/ha/day, respectively. Crude protein and NDF differences (P<0.05) were also found between the clones for all the different parts of the analyzed plant. The forage lost presented a similar chemical composition to the leaf blades above 40cm and to the post-grazing residue. The clones CE-08-AD and Venezuela AD presented a high performance considering the evaluated parameters and may be considered as promising materials.
Objetivando selecionar clones de capim-elefante para utilização sob pastejo, realizou-se experimento num delineamento em blocos ao acaso, com quatro repetições e 16 tratamentos, no período de 15/07/99 a 19/04/00. Em parcelas com 25m2, foram estudados a taxa de acúmulo de lâminas foliares (LF) e de colmos (C), teores de matéria seca (MS), proteína bruta (PB) e fibra em detergente neutro (FDN). Houve diferença significativa (p<0,05) entre clones e períodos de avaliação para produção de LF acima de 40cm, produção total de LF e produção total de forragem, com valores médios de 28,08; 41,62 e 49,18kg/ha/dia, respectivamente. Os teores de PB e FDN também foram diferentes (p<0,05) entre os clones em todas as frações da forragem. A fração perdas de forragem apresentou qualidade semelhante às frações LF acima de 40cm de altura de resíduo pós-pastejo. Os clones CE-08-AD e Venezuela AD destacaram-se para a maioria dos parâmetros avaliados, mostrando-se promissores.