Roberson Machado Pimentel

Structure of signal grass pasture with height variation

This study was carried out aiming to evaluate the structural characteristics of Brachiaria decumbens cv. Basilisk pasture. Four heights of plants (10, 20, 30 and 40 cm) were evaluated within the same grazing area in a randomized block experimental design with two repetitions. Variation in the initial height of the signal grass pasture plant showed a linear and a negative response. The masses of green leaf blade mass, live stem, dead material, live forage and total forage linearly increased with heights of the plants on the pasture. However, it was observed a linear reduction in green leaf blade/live stem ratio and the height of the plants on the pasture (from 1.16 to 0.58). Plant height on the pasture had a stronger effect on the increase of live stem and the dead material masses than it had on the green leaf blade mass. Volumetric density of green leaf blade decreased (from 97.09 to 39.07 kg/cm ha DM) with plant height on the pasture. The same response was found for volumetric densities of live forage (from 181.62 to 107.85 kg/cm.ha dry matter) and total forage (from 283.39 to 195.72 kg/cm.ha dry matter). On the other hand, the plant heights on pasture did not affect volumetric density of live stem and dead material, which showed mean values 80.95 and 95.61 kg/cm.ha DM, respectively. The heights of the plants on pasture had a quadratic effect on light interception by the canopy. Grazing areas with heights of 10, 20, 30 and 40 cm showed light interception values of 56.15, 85.16, 93.39 and 96.57%, respectively. It occurs and temporal variabilities on the B. decumbens pasture structure managed under continuous stocking.

Características estruturais do pasto de capim-braquiária de acordo com a localização das fezes

The objective of this study was to evaluate the effect of the cattle feces location on the characteristics of vegetative and reproductive tillers, dry mass content in plant components, forage volumetric density and Brachiaria decumbens cv. Basilisk pasture height managed under continuous stocking. It was used a randomized block design with three repetitions in a split-plot scheme considering the plots the sites next and far from feces and the sub-plots were the vegetative and reproductive tiller categories. Dry mass content of live foliar blade (LFB) per tiller in sites near the feces (0.14 g) was higher than in the sites distant from the feces (0.08 g), opposing to what was verified for composition of dry matter of dead foliar blade per tiller. Content of LFB dry mass in vegetative tillers (0.15 g) was higher than in the reproductive tillers (0.06 g). On the other hand, composition in stem dry matter (0.38 g) and in dead foliar blade (0.20 g) were higher for reproductive tillers. Tiller weight of the plants near the feces was higher (0.58 g) than those far from the feces (0.17 g). On sites near the feces, the number of vegetative tiller was lower, while the number of reproductive tiller was higher. Higher contents of dry matter of the green stem, green forage and total forage of the pasture were observed on sites close to feces when compared to the far ones. The same result was obtained for the pasture height. The Brachiaria decumbens pasture structure is modified by the position of the cattle feces. Cattle feces droppings are a heterogeneous spatial factor of vegetation on grazing areas.