Tropical Grasslands (2001) Volume 35, 151161
Tiller dynamics in a bahia grass (Paspalum notatum) pasture under cattle grazing
M. HIRATA and W. PAKIDING
Grassland and Animal Production Division, Faculty of Agriculture, Miyazaki University, Miyazaki, Japan
Tiller dynamics were monitored for 4 years in a bahia grass (Paspalum notatum) pasture under cattle grazing. Total tiller density ranged from 3819–4875 tillers/m2. Tiller appearance rate (TAR) ranged from 0.10–35.42 tillers/m2/d (0.02–12.03 tillers/1000 tillers/d), usually showing distinct peaks in late spring (May) or early summer (June). Tiller death rate (TDR) ranged from 0.52–17.30 tillers/m2/d (0.14–3.79 tillers/1000 tillers/d), with a tendency to peak in summer (June–August). The balance between TAR and TDR was positive in late spring (May) or early summer (June), and usually negative or close to zero in the other seasons. Relative TAR increased as leaf appearance rate (LAR) increased to about 0.09 leaves/tiller/d. Thereafter, the rate continued to increase with increasing LAR in spring (March–May), whereas it remained almost constant in summer and autumn (June–November). The rate of site filling, ranging from 0.0032–0.0461 tillers/leaf, decreased as herbage mass increased to about 77 g DM/m2, and remained almost constant thereafter. Relative TDR increased exponentially with increasing mean daily air temperature. Tillers formed in autumn survived longer (half-life = 737 d) than those formed in the other seasons (half-life = 403–559 d). The results confirm that bahia grass tiller density remains stable because tillers are long-lived despite low rates of tiller appearance. The results also indicate that low relative TAR in bahia grass is attributable to low rates of site filling.