Effect of slope on some soil characteristics at Wadi Naghamish, North Western Coast of Egypt

Taher M. H. Yossif and Gihan. M. Ebied

This study aims to assess the effect of both of aspect and slope gradient on some soil characteristics in a representative watershed in the NW coastal region of Egypt. Topsoil samples (0 – 25 cm) were collected from thirty sites approximately evenly distributed over the entire watershed; depending on a particular combination of major slope gradient and aspect of soils by using the spatial analyst function in Arc GIS software. Soil samples were analyzed for physical, chemical and nutritional routine characterizations. A factorial model on the basis of randomized complete block design was used to analyze the soil data. The results based on statistical analysis showed significant differences between soil characteristics of coastal plain (having none of both aspect and gradient) and those of other different slope aspects and gradient at 5 % level of confidence. The magnitude of some soil physicochemical characteristics and available nutrients such as clay, active calcium carbonate, EC, OM, soil pH, N, P, and K is significantly higher in the coastal plain soils compared to northern, eastern and western slope aspect and low, medium and high slope gradient. However, the available Fe was significantly higher in the west facing slope and high slope gradient than the other aspect and slope gradient. The differences in available nutrients of Mn, Zn and Cu were not related to slope gradient across soils on all slope aspects and gradients of the study area. Also, the results showed that aspect and slope gradient had an effect on spatial heterogeneity and distribution of some soil characteristics and nutrients resources in the NW coastal region of Egypt.