Cool Season Production of Tropical Grasses
Arthur Cameron, Principal Pastures Agronomist, Darwin
There is interest in growing fodder under irrigation during the Top End dry season to supply hay to live cattle export yards and cubing/pelleting plants.
Tropical grasses generally do not grow well under irrigation during the cooler months of the year in the Top End. Sugargraze forage sorghum (Sorghum sp) and Finecut Rhodes grass (Chloris gayana) have been shown to produce commercial yields of 25 to 35 tonnes per hectare per year at Douglas Daly Research Farm. Both of these options for fodder production under irrigation have limitations. The Forage sorghum generally needs to be re-sown every year to maintain a productive stand. In the Top End, the Finecut Rhodes grass is not liked by cattle as a fodder, and it has a high tensile strength, which makes it difficult to grind and make into fodder cubes and pellets.
There are a number of other tropical grasses which have cold tolerance and may be suitable as alternatives to Forage sorghum and Finecut Rhodes. The cool season growth of seven other tropical grasses is being compared with that of Finecut Rhodes at Coastal Plains Research Station to select one or more cultivars, which have equivalent or better cool season growth, better acceptance by cattle and better grinding characteristics.
Seven of the grasses were sown by seed in December 2014. The eighth grass, Strickland finger grass, was planted by runners in February 2015. The first year’s yield results are presented in Table 1 (below). The establishment was good except for the Premier digit grass, which was attacked by Crab grass leaf beetle larvae. While Strickland finger grass and Premier digit yields were lower overall, the yields were similar for all of the grasses at the final harvest.
The trial will continue this year to get a full dry season’s results. Samples from each harvest will be submitted for nutrient and quality analysis.
Table 1. Dry Matter yields of cool season grasses
DM kg/ha (2015)
Total DM Kg/ha
Strickland finger Grass
*Strickland finger grass yield was decreased by selective grazing by wallabies prior to the 11 August harvest
Last updated: 20 September 2019