The aim of this study was to verify patterns of tiller population density, tiller appearance and mortality rates, proportion of flowering tillers and herbage dry matter accumulation for Cynodon spp. (cv. Tifton 85). Treatments corresponded to four "steady state" conditions characterised by sward surface heights of 5, 10, 15, and 20 cm, maintained by sheep grazing under continuous stocking and variable stocking rate. Treatments were allocated to experimental units (400 m² each) according to a completetely randomised block design with four replication. Tillering evaluations consisted of tagging and counting all tillers present and new tillers emerging within two 15 cm diameter plastic rings (PVC) per experimental unit. Herbage accumulation was measured using exclosure cages rotated every three weeks. There was a time effect (P<0,10) for all response variables studied. Short swards (5 cm) presented the highest values for tiller population densities as well as the highest rates of tiller appearance and mortality. Tiller mortality rates were very influential on tiller density population. A great turnover in tiller population occurred during the summer period, suggesting that a high tiller population density should be maintained during autumn and winter. There was no treatment effect on herbage accumulation rates (P>0,10).
tiller population; tiller mortality; flowering tillers; herbage accumulation