Determination of n-Alkanes at Different Stratum Heights in a Pasture of Panicum maximum cv. Mombaça

Determination of n-Alkanes at Different Stratum Heights in a Pasture of Panicum maximum cv. Mombaça

The aim of this experiment was to determine n-alkane levels in the stem + leaf sheath and leaf blade components of a pasture of Panicum maximum cv. Mombaça, harvested in 20 cm stratified layers. This pasture was under rotational grazing for intensive beef production throughout the year. The grazing system was based on the use of 16 paddocks with a 2-day grazing period followed by a 30-day resting period. Profiles of n-alkanes were determined in samples harvested in three separate periods: in the middle of the dry season (August 97; PERIOD 1), at the beginning of the wet season (November 97; PERIOD 2) and at the end of the wet season (April 98; PERIOD 3). Chain length was measured in the range from C₂₇ to C₃₅. Within the three sampling periods, C₃₃ and C₃₁ were the most abundant alkanes, both in the stem + leaf sheath and leaf blade. The effect of sampling periods and pasture heights on n-alkane profiles were observed for the leaf blade component only.