Productivity and reserve carbohydrates of pastures under cutting intensities

There is a need to better understand the effects that cutting or grazing exert on forage, thus to facilitate planning of management that will not be detrimental to the productivity or persistence of the plants. To this end, experimentation was conducted in the pastures of the Experimental Station of Empresa Pernambucana de Pesquisa Agropecuária, Itambé-PE to determine the effect of height of cutting on dry matter production (DMP), daily rate of DMP, total N accumulation, and concentration of reserve carbohydrate (RC) in the herbage. A completely randomized experimental design was used, with five replicates per treatment: Brachiaria decumbens and B. humidicola cut at heights of 5, 15, and 25 cm and at 25 cm plus 80 kg of N/ha; and Pennisetum purpureum cut at 5, 25 and 50 cm and 50 cm plus 80 kg of N/ha. Four cuttings took place, the first during the transitional season from dry to wet (Februrary 2001), and three during the wet season (April, July, and August 2001). The 5 cm cutting height resulted in the greatest DMP and total N accumulation. There was a tendency toward higher concentration of RC in the grass harvested in the transition period during which B. decumbens showed higher RC values than the other two species