There have been few attempts to examine, in any systematic manner, the variability
of water runoff and soil erosion on different terraces in one area. Also, relationships
with independent variables, such as rainfall amount and intensity, and soil and
vegetation characteristics, have only been investigated in a very rudimentary fashion.
The methodology adopted in this study was designed to examine many of these
factors. Following a pilot study of terrace shape and form and surface soil textures,
nine terraces were selected for detailed study (Fig. 5). These were chosen to be
representative of the common terrace morphologies, and to encompass the range of
surface soil textures, including the finer-textured red soils. Thus, the study was
designed to be illustrative of the processes occurring and not universal. The implications
of this are discussed below when the significance of the results are examined.
The chosen terraces also included those on the lower, more productive lands and
the higher, more marginal and less productive/less fertile areas. All terraces were
subject to the same cropping cycles and broadly similar land management regimes.
It is important to note that very steep terraces (10°) were not monitored, partly
owing to the physical difficulty of so doing with a reasonable degree of accuracy,
and partly because they are not common in the study area.