The Effects Of Burning On Grazing Resources In Nairobi National Park

Abstract

A study of the effects of burning on grazing resources was conducted from July, 1978 and July, 1979 in the grasslands of Nairobi National Park. The aims and scope of this study were to (a) Examine the effects of experimental burning on the grass and on soil nutrients over a short period. (b) Study fire rate of spread. (c) Study the extent and effects of wildfires in the Park. (d) Study the effects of f ire on woody species. (e) Propose a burning programme for this Park. Results from all the study sites on standing crop reflect a very high proportion of dead grass in unburnt plcts even in the middle of the rainy season. Nutrient analysis showed that new growth of grasses in the burned plots had a higher nitrogen content and were thus likely to be favoured by herbivores. Since the palatability aRc digestibility of the living grass declines a~ it grows old, the ·results show the importance of burning in reducing the amount of unpalatable, less nutritious materials. There was no notable loss in soil nutrients both 30 minutes and two months after experimental burning. A slight reduction in the number of woody plants was noted in burnt plots. The speed of the backfires varied inversely with the wind velocity, being lowest where the opposing wind velocity was highest. The largest amounts of ash were formed where the vegetation standing crop was highest before burning in the experimental plots. The results obtained indicate that a rotational burning scheme can be recommended. Such a programme would initially be experimental and its effects carefully monitored. The frequency and the time of prescribed burning would depend on the amount of accumulated grass, which in turn is dependent on precipitation and grazing intensity in this Park .