The sward height at the early stockpiling period modifies the structural characteristics of marandu palisadegrass under continuous stocking

The control of sward height at the early stockpiling period influences the structural characteristics of stockpiled sward in winter. So, we conducted this work on the Cerrado region of Brazil based on the hypothesis that the reduction of pasture height at the beginning of stockpiling period results in: (i) lower stock of forage mass; and (ii) higher live leaf mass, but lower stem mass in stockpiled pasture during the winter. The treatments were four sward heights (15, 25, 35, and 45 cm) at early stockpiling period of marandu palisadegrass (Brachiaria brizantha syn. Urochloa brizantha cv. Marandu). The experiment was conducted in a completely randomized design, with three replications (paddocks with 800 m²). The stockpiled swards were evaluated during the grazing period in winter on days 7 (beginning), 45 (middle) and 90 (end). The vegetative tiller number (VEGT), live leaf mass (LLM) and leaf area index (LAI) were greater in the 15 cm stockpiled pasture than the other treatments. Greater heights (35 and 45 cm) at stockpiling resulted in greater forage mass than lower heights (15 and 25 cm). The VEGT, LLM, number of reproductive tillers, live stem mass, forage mass and LAI values were higher at the beginning than at the end of the grazing period. Our hypothesis has been proven, so that the reduction of sward height of the marandu palisadegrass at the beginning of the stockpiling period results in lesser forage mass, but with better structural characteristics.

How does the initial sward height and the grazing period influence the spatial variability of vegetation in deferred signal grass pastures?

The objective of this study was to evaluate the spatial variability of structural characteristics of deferred pastures of Brachiaria decumbens cv. Basilisk (signal grass) subjected to associations of sward heights (10, 20, 30, and 40 cm) at the beginning of deferment and grazing periods (1, 28, 56, 85, and 113 days). The experiment was arranged in a split-plot and completely randomized-block design with two replicates. Pastures remained deferred from March to June 2010. From June to the beginning of October 2010, deferred pastures were utilized by steers under continuous grazing and at a fixed initial stocking rate of 3.5 AU ha-1. At the beginning of the deferment, the coefficient of variation (CV) for pasture height was reduced linearly with the pasture height. During the grazing period, in the winter, the CV for pasture height was not influenced by initial pasture height; however, it responded quadratically to the grazing period, with a maximum value of 36.4% at 71 days of the period of utilization. The CV for tiller height was reduced linearly with pasture height at the beginning of deferment but increased linearly along with the grazing period. The initial pasture height did not change the CV of the falling index. However, the latter was quadratically influenced by the grazing period, with a maximum value of 59.5% at 67 days of the utilization period. Signal grass pastures deferred at a lower height have a higher spatial variability of the vegetation. In the grazing period, there are changes in the spatial variability of the vegetation of the deferred signal grass.