Biomass, Shoot-Production and Grazing of Two Grasslands in the Rwenzori National Park, Uganda

Strugnell, R; Pigott, C

(1) In grasslands in Uganda dominated by Hyparrhenia filipendula and Themeda triandra, biomass of shoots increases to about 0+5-0+7 kg m-2 in the rainy season without grazing, and to about half this value with grazing. Maximum leaf-area index in unglazed grassland generally does not exceed 3+0. Biomass of roots varies seasonally from 0+5 to 2+0 kg m-2 (2) In this grassland, and in grassland dominated by Sporobolus pyramidalis and Chloris gyana, the quantities of dry matter which can be harvested by successive monthly cuts at 5 or 20 cm above the ground vary from almost nothing in dry season to the equivalent of 4 or 2 g m-2 per day dry matter production respectively in rainy seasons. (3) These values are for grassland not grazed by large animals; with grazing the rates are approximately halved, and the differences provide estimates of the rates of natural grazing. (4) The mean values for the rate of grazing throughout the year are of the same order of magnitude as values calculated from estimates of the energy requirements of the biomass of large mammals on the sites. (5) Monthly production of dry matter and protein are significantly correlated with rainfall, giving regression constants of 6+8 g m-2 dry matter and 0+56 g m-2 protein per month per cm of rain

Biomass, Shoot-Production and Grazing of Two Grasslands in the Rwenzori National Park, Uganda

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