Rangeland utilisation assessment and modelling for grazing and fire management

To support grazing and fire management of communal semi-arid to sub-humid African rangelands, the assessment of grazing capacity is illustrated for cattle. The forage dry matter intake (DMI) was divided into four components: 1) the mature standing crop, 2) the green part of the standing crop, 3) the regrowth after range fires, and 4) browse. The relationship between the potential DMI and the crude protein (CP) concentration of the forage was modelled. The DMI ranged from 5 to 50% for forage with low to high CP concentrations, respectively. The DMI of browse was fixed at 0 and 10% of the DMI of unburnt vegetation for plain and woodland systems, respectively. The potential DMI of the four forage components combined, based on data of the early- to mid-dry season, was matched with livestock requirements to calculate grazing capacities. Possible combinations of and changes in the forage components, representing grazing capacities for different seasons of the year, were calculated and visualised. Lastly, it was demonstrated how to assess the proportion of the rangeland that should be burnt to make optimal use of the low quality forage available in abundance and the small amount of high quality regrowth.