Abstract:

many other crops, thus rapidly decreasing the fertility of the soil and consequently requiring
regular inputs of chemical fertilizers. Tobacco crop is also prone to several diseases and
insect pests especially in early stages and. therefore requiring pesticides application to
However, the environmental impact of these requirements
particularly on flora diversity is not well documented in Uganda. During the period of two
growing seasons, weed prevalence in Kigorobya and Kitoba sub counties of Hoima district
tobacco after bush fallow. (2) two consecutive tobacco crops after bush fallow, and (3) three
consecutive tobacco crops after bush fallow. A comparative study was made to elucidate
whether similar patterns of change in the flora were evident under maize crops grown as
active fallow after the various tobacco crops under similar agricultural regime. At the
beginning of the experiment a survey of nearby bush fallow land was undertaken to act as
control in assessing differences in vegetation dynamics.
Tobacco production incorporating the use of agro-chemicals did not have adverse effects on
cither diversity or prevalence of the common macro-flora. Most of the grass species failed to
show any recovery by the third cropping cycle of tobacco and the maize fallow break after
tobacco cultivation while the broad leafed weed species showed increase from bush fallow
under tobacco cultivation. Prevalence scores of weeds species such as E. floribundns, E.
hirta, G. parviflora, M. merculiasis, D. velutina and C. benghalensis remained unchanged
under the maize fallow breaks. Total viable counts of bacteria, fungi and bean nodulating
rhizobia were not significantly affected by tobacco growing or the subsequent maize fallow
break.
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L
Tobacco (Nicoliana tabacun, I.) growing takes up soil nutrients at