Climate, nitrogen and grass. 5. Influence of age, light intensity and temperature on the production and chemical composition of Congo grass (Brachiaria ruziziensis Germain et Everard).

Abstract

Brachiaria ruziziensis was grown in pots at 24/19, 28/24.5 and 33/25 deg C at 160, 279 and 621 cal/cm2 day with 15-16 h light/day, and cut after 2, 3, 4 or 5 weeks of regrowth. DM production was higher after the longer regrowth periods as a result of a small increase in tiller number and a large increase in tiller weight; this was accompanied by a decrease in percentage leaf and in percentage organic N and ash and by an increase in the CF content of stems, while the CF content of leaves did not change. Increased light intensity resulted in increased DM production because of a sharp increase in tiller number; average tiller weight was not affected, nor was percentage leaf or percentage organic N, but percentages of nitrate-N, ash and CF in leaf and stem were decreased. Higher temperatures increased DM production, and gave a sharp increase in tiller weight accompanied by a decrease in percentage leaf and percentage organic N and an increase in percentage CF, but tiller numbers were reduced. Temperature had a direct effect in increasing percentage CF in leaves and stems; this was considered to be a direct cause of poor quality herbage in warm climates. Result indicated that light and temperature affected herbage quality partly through effects on morphological composition and partly by direct effects on the composition of the various morphological fractions. (Abstract retrieved from CAB Abstracts by CABI’s permission)