Hybrid pennisetum in a warm temperature climate: regrowth and stand-over forage production

Abstract

Dry matter, tillering and herbage quality changes were examined in hybrid pennisetum (Pennisetum americanum x P. purpureum) over 15 weeks of uninterrupted regrowth in summer and autumn, and in regrowth of differing ages throughout autumn until frosting. During uninterrupted regrowth above-ground dry matter accumulation was slow until internode elongation, at which time the apparent utilization of visible radiation was 10 per cent. Nitrogen and organic matter digestibility percentages declined with age except during internode elongation. The dry matter yield was high (12 t ha-1) but the quality of the forage poor after 12-13 weeks. When defoliated in summer and autumn the rate of regrowth decreased as defoliation was delayed. Nitrogen concentration decreased during autumn and fell rapidly after frosting; digestibility also decreased with time but increased with lateness of defoliation when forage was compared at the same age. Defoliation in mid-February was recommended to provide a reasonable yield of stand-over forage containing adequate concentrations of crude protein and digestible organic matter.