Sediment discharge into Lake Malawi is threatening its ecological importance, thereby
inflicting serious socio-economic consequences upon people dependent on this ecosystem.
The discharge is attributed to high rates of erosion in the Lake's catchment, principally
occurring on agricultural land. This study examines how survival strategies, such as
expansion of cultivated farmland and use of low fertilizer application rates, enhance
the likelihood of erosion in the Linthipe River Catchment - one of the Lake's important
river catchments. As such, it shows that the magnitude of erosion is significantly
correlated to the amount of farmland cultivated by estate farmers and smallholders
(r = 0.18, P = 0.03, and r = 0.19, P = 0.003 respectively). The low correlation
coefficients uphold the long-established fact that physical variables such as soil
erodibility (vulnerability of soil to erosion), rainfall erosivity (the potential of
rainfall to cause erosion), and topography, also play major roles in erosion processes.
Nonetheless they do show that area of cultivated land contributes to erosion.
Additionally, the study shows that yields of important crops such as maize and
tobacco are low because of insufficient use of fertilizers. To compensate for the
low yields, farmers rely on extending sizes of land that they cultivate thereby
exposing more land to erosive forces of rainfall. The study, therefore, concludes
that Lake Malawi's biodiversity is under threat. In order to sustain the biodiversity,
it is necessary to eliminate the need to increase farmland by means of agricultural
intensification that incorporates appropriate soil-conservation measures.