A comparative analysis of the morphology and nutritive value of five South African native grass species grown under controlled conditions.

Abstract

The comparative growth habits and nutritive value of native grass species of South Africa are largely unknown despite the utility of this information in rangeland restoration efforts. This article presents a comparative characterisation of the morphology, chemical composition and in vitro ruminal fermentation of Urochloa mosambicensis, Cymbopogon pospischilii, Eragrostis superba, Fingerhuthia africana and Eragrostis bicolor when grown under controlled conditions. Species were analysed for height, number of leaves, number of tillers, stem diameter and leaf width at different growth stages, whereas chemical composition and in vitro ruminal dry matter degradability (DMD) were assessed at maturity stage. Grass species and growth stages significantly influenced morphological characteristics. Eragrostis superba and U. mosambicensis had the highest number of leaves at the reproductive stage. Urochloa mosambicensis ranked highest in terms of rangeland restoration potential when all morphological parameters were considered, followed by E. superba and C. pospischilii. With the highest crude protein, low acid-detergent lignin and higher DMD at 48 h, F. africana and C. pospischilii have the highest potential feed value. Across the three most suitable native grass species, U. mosambicensis, E. superba and C. pospischilii, there is sufficient genetic diversity that suggests that these plants may play different and complementary ecological roles in the communal rangeland ecosystem.