Abstract
M.Sc. (Geography)
The 1982/1983 drought in the summer rainfall regions of South Africa
highlighted the dependence of the agricultural sector as well as the
general economy of the country on climatic vagaries. The results as
indicated in this dissertation fonn a basis for the development of a
yield prediction model for maize in the south-eastern Transvaal. The
study consists of two parts, namely:-
a) The delimitation of the south-eastern Transvaal into smaller homogeneous
rainfall regions.
b) An investigation of spatial and temporal rainfall patterns within
each region and over the study area as a whole.
a) The delimitation of the south-eastern Transvaal into smaller homogeneous
rainfall regions: Various methods were investigated for this
purpose and T-mode Principal Components Analysis with the subsequent
clustering of component scores were found to be the most acceptable.
b) An investigation of spatial and temporal rainfall patterns within each
region and over the study area as a whole: Various parameters such as
rainfall amount~ number of rain-days~ rainfall intensity~ seasonality
and variability of rainfall were analysed. The presence of rainfall
cycles and absence of linear trends were established. The orographic
effect of the Eastern Escarpment on the spatial distribution of rainfall
amount, frequency and intensity is clearly shown.
Areas where conditions are less suitable for the dry-land cultivation
of crops due to factors such as rainfall variability (in excess of
30%), steep slopes and relatively low rainfall intensity, were identified.
Significant correlations were found between spring and late summer
rainfall of a dry year