Effects of physiographic units on the relationship between cropping frequency and level of soil erosion in Nyakach District, Kenya.

A number of scholars agree that farms which are cropped more frequently tend to exhibit lower levels of soil erosion than those that are cropped less frequently or left fallow. However, the effects of physiographic units on this relationship are not known. Most methods used to assess land degradation ignore the use of indicators of agricultural land use intensity and land degradation. They are too complex and ignore the role of physiography. This research looked at the effects of different physiographic units on the relationship between the frequency of cropping and the level of soil erosion in Nyakach District of Kenya. The study focused on establishing the relationship between cropping frequency and level of soil erosion in the Plateau, Scarp Slopes, Plains and Valley Bottoms. Purposive and simple random sampling was used to select 384 out of 29,214 farmsteads. Correlation and regression analyses were employed to assess the nature and strength of the relationship between the cropping frequency and the level of soil erosion in the four different physiographic units of Nyakach. Significant relationships occurred in all the four physiographic units with r = -0.347 for the Plateau, r = -0.318 for the Scarp Slopes, r = -0.412 for the Plains, and r = -0.43 for the Valley Bottoms. The researchers concluded that physiographic units have a significant influence on the relationship between cropping frequency and level of soil erosion in Nyakach District. It was therefore recommended that cropping frequency and level of soil erosion be used for assessing land degradation in specific physiographic units of Nyakach District.