Effect of Climate Changes and Coefficient of Surface Roughness on Soil Loss by Wind Erosion in Some Central and Southern Iraq

Abstract

"act Woodruff and siddoway, 1965, established an equation for the estimation of soil Loss by wind erosion called Wind Erosion Equation (WEQ); solution of this equation gives the maximum amount of wind erosion under certain field conditions and is considered evidence in identifying the necessary methods for treating wind erosion in those conditions (Eltaif et al.,1991). This study aims to find out the extent to which climate change in the Samawah region of southern Iraq and Baghdad in central Iraq over a period of 34 years has affected values of soil losing by wind erosion using equation of (woodruff and siddoway, 1965) and effectiveness of this changes in soil surface roughness factor in reducing or increasing these loss. Two sites were selected located within central and southern regions of Iraq, one in Al-Jadiriya area in Baghdad governorate and the other in Samawah area in Al-Muthanna governorate. The results showed that estimated soil losing for years (1980-2013) in Al-Jadiriya decrease annually by 10-30 kg.hec.-1.year-1, while samawah increase by 240-760 kg.hec.-1.year-1. The effect of surface roughness factor was significant in reducing soil loss during period of study. Roughness factor for ridge (0.5) has reduced soil losing by 2.6 times compared to non-ridge soils (1).The ratio in semi-bridge soil (0.75) was 65%. This is due to the impact of bridge in reducing wind speed and reducing its erosivity. The general direction of soil loss indicates decrease in Al-Jadiriya area and increase in Samawah area with the case of fluctuation in soil loss between high and low of general direction line due to climate factor (C) in general equation of soil loss and it reflects ability of wind erosion, so decreased when wet conditions improved, by increased rainfall, reduced evaporation and increasing when dry conditions dominate Corresponding author: E-mail( mohammed.alrawi@coagri.uobaghdad.edu.iq ) All rights reserved AlMuthanna University"