Annual Forage Accumulation and Nutritive Value of Juncao Grass (Cenchrus fungigraminus) Under Increasing Pre-Harvest Canopy Heights

Juncao grass (Cenchrus fungigraminus Z.X. Lin, D.M. Lin, and S.R. Lan) is a recently developed C₄ forage which has been introduced to several tropical countries supported by different aid programs. However, there is no information on the potential of forage production, nutritive value, and agronomic characteristics of this new species to support management recommendations. This research aimed to compare two cultivars of Juncao to Guatemala (Tripsacum andersonii J.R. Gray) and Elephant grass [Cenchrus purpureus (Schumach.) Morrone cv. Napier] in relation to annual forage production and nutritive value subjected to different pre-harvest canopy heights. The trial was designed using randomised blocks (n = 3) in a split-plot arrangement where pre-harvesting canopy heights (0.5, 1.0, 1.5, and 2.0 m) composed the main plots and forage species/cultivars (n = 4) as the subplots. The annual forage accumulation of Juncao green and purple was approximately double that of Elephant and Guatemala grass when averaged across 2 years, while crude protein and metabolisable energy concentration was similar to Elephant and higher than Guatemala grass. Juncao green and purple cultivars should be harvested between 1 and 2 m of pre-harvest canopy height, with shorter pre-harvest targets favouring nutritional value and taller targets promoting greater biomass production per harvest, although no increments in annual forage accumulation were observed when pre-harvesting canopy height was over 1 m. The high forage production of Juncao grass, combined with its nutritional value comparable to other tropical forage, indicates substantial potential for its adoption in cut-and-carry systems in the wet tropics.