Grazing management and planning of animal production systems from pastures are essentially based on estimates of herbage mass, production and accumulation rates. This work evaluated two methods, sward stick and rising plate meter, for estimating herbage mass in pasture areas formed by Cynodon spp. cultivars Florakirk, Tifton 85 and Coastcross. Paddocks were maintained at 5, 10, 15 and 20 cm sward surface height through continuous stocking with sheep, according to a complete randomized block design with four replications. Over twelve months, calibration equations of stick and plate sward height versus the correspondent herbage mass were generated. As a result, four y = a + bx type calibration equations (y is the herbage mass in kg ha-1 and x is the sward height) were obtained. Most of the variation among cultivars and seasons of the year occurred in intercept values (a) and less in slope values (b). This variation was related to modifications in sward structure, particularly in dead material content. The methods did not differ in precision, although the rising plate meter proved to be faster and more agile. Calibration of both methods must be specific for each cultivar and carried out regularly in order to result in precise equations capable of generating reliable estimates of herbage mass.
grassland management; planning; calibration
