1119
Morphological Composition of Piata Palisade Grass Tillers Subjected to Strategies of Intermittent Defoliation*
It was aimed to evaluate the morphological composition of tillers of Piata palisade grass (Brachiaria brizantha cv. Piata) under different combinations of defoliation frequency and severity. The trial was carried out in Vicosa - MG, Brazil, from December 2012 to March 2013. The treatments corresponded to combinations of two post-cutting heights (15 and 20 cm) and two pre-cutting frequencies (95% and maximum canopy light interception, LI95 and LI100) and were allocated to experimental units (14 m2) according to a 2x2 factorial arrangement in a randomized complete block design with three replications. Canopy light interception was performed using a canopy analyser LAI 2000 and sward height using a sward stick. The following variables were evaluated: the number of live and dead leaves per tiller, the length of leaf blades and the length of stem. Data were analysed using the mixed procedure of SAS. The number of live leaves was not affected by management strategies (P>0.10), staying on average 4.5 live leaves per tiller. However, the number of dead leaves per tiller was lower (P<0.10) for swards managed with the LI95 target than those managed with the LI100 target (1.25 and 1.79, respectively). Additionaly, swards managed with the LI95 target had lower (P<0.10) stem length (19.15 cm) than those managed with the LI100 (27.76 cm). The length of leaf blade also was lower (P<0.10) with LI95 target than with LI100 (18.04 and 27.43 cm, respectively). There were no effects (P>0.10) of two post-cutting heights (15 and 20 cm) on all variables evaluated. The Piata palisade grass managed with the LI95 target had lower number of dead leaves and shorter length of stems and leaves, which corresponds to more favorable sward structure to intake by grazing animals.
*Funded by Fapemig.
Keywords:
management, pasture, tropical grass