Leaf tissue fluxes of Pampa biome native grasses submitted to two grazing intervals

Leaf tissue fluxes of five Pampa biome grasses (Andropogon lateralis, Aristida laevis, Axonopus affinis, Paspalum notatum and Paspalum plicatulum) were evaluated in a natural pasture under rotational stocking with heifers in the spring and summer from October 2010 to April 2011. The experimental design was completely randomized, with two grazing intervals, defined by thermal sums of 375 and 750 degree-days, and the five grass species. The evaluated species had a higher growth flux and balance between the fluxes when subjected to a grazing interval of 750 degree-days and a higher real efficiency of utilization when subjected to grazing interval of 375 degree-days. Andropogon lateralis showed the highest growth, intake and senescence fluxes: 3.61, 2.37 and 3.04 kg DM ha(-1) day(-1) respectively. Aristida laevis had the lowest real efficiency of utilization.