Abstract:
Soil erosion and resulting land degradation have been identified as serious problems since the 1920s in Tanzania. Soil erosion in Tanzania is mainly water induced and results from rainwater runoff on fragile lands such as steep slopes, overgrazed lands and other degraded lands due to various factors like deforestation and over-cultivation. This paper discusses a study carried out to assess the contribution of soil properties to soil erosion in the Northern slopes of the Uluguru Mountains. Two geomorphic units along mountain ridges and foothills on slopes ranging from 30 to 70% were studied for various soil physical characteristics including clay ratio, dispersion ratio, particle size analysis, bulk density, infiltration rate, gravel content, aggregate stability and soil loss due to erosion. Results from the study revealed that on one hand high soil organic matter, dry stable aggregates (>2 mm), bulk density and infiltration rate reduce significantly (P< 0.05) rill and interrill erosion. On the other hand, clay ratio, silt, very fine sand and gravel content increase soil erosion. The study argues that the application of organic material would improve soil physical properties and hence reduce soil erosion. Appropriate farming practices such as terracing, contour farming strip farming among others which stabilise soil aggregates are also recommended to minimise soil erosion.
