An evaluation of the production potential of six tropical grasses under grazing. 1. Yield and yield components, growth rates and phenology

Abstract

Fertilised pastures of 4 varieties of Setaria sphacelata (var. splendida and cvv. Nandi, Narok and Kazungula), pangola grass (Digitaria eriantha ssp. pentzii) and kikuyu grass (Pennisetum clandestinum cv. Whittet) were grazed rotationally over a 3-year period at Beerwah, south-eastern Queensland. Each variety was grazed on a 5-weekly rotation by 2 leaders for 7 days; a follower herd including 2 testers grazed the regrowth for 7 days. The numbers of followers were subjectively adjusted weekly, depending on feed available. The experiment was designed to provide adequate quantities of forage of maximum potential quality to the leaders throughout the year. There were large and frequently consistent differences between the grasses in yield and its various components, leafiness, leaf and forage density, rate of development of leaf dry matter, and time and intensity of flowering under the management system imposed. Of particular interest were the high leaf yield of Narok, high overall yield of Narok and var. splendida, low rate of development of leaf area index of pangola grass and kikuyu grass, and high forage density of kikuyu grass. These differences might be expected to have an effect on pasture quality, carrying capacity and optimal management strategy.