Assessment and Mapping of Wind Erodibility of Aridisols and Entisols in the Red Sea State, Sudan*

Abstract

Wind erodibility of a soil (WE) is a major indicator of its
susceptibility to wind erosion under a given climatic condition. This study
is part of a national project for assessing and mapping wind erodibility of
soils in Sudan. It was undertaken to generate WE data for the Red Sea
State. Three replicate surface soil samples were collected, randomly, from
twenty-eight geo-referenced farms spread in the State. Non-erodible soil
particles (NEP>0.84mm) and selected soil properties were measured
using standard procedures. The mean NEP values ranged from 17.0% to
57.2% with an overall mean coefficient of variation of replicate
determinations equal to 4.7%. The equivalent WE ranged from 49.6 to
244.0 ton/ha. The results showed a highly significant (P<0.001) increase
of NEP with increase of clay (C) and organic matter (OM), and decrease
with increase of sand and sand plus silt (S+Si) expressed, successively, as
ratios of clay, clay plus OM and clay plus CaCO3 . The reverse trends
were obtained for the relations of WE and the various soil properties and
their ratios. Clay, (Si+S)/C, (Si+S)/(C+OM) and (Si+S)/(C+CaCO3 )
accounted for 80%, 81%, 81% and 82% of the variation of NEP, and
77%, 78%, 78%, and 79% of the variation of WE. Multiple regressions
relationships of NEP or WE with clay, sand, CaCO 3 and OM gave
coefficients of determinations equal to 81% and 80%, respectively. Thus,
it was recommended that clay, (Si+S)/C, (C+OM), (C+CaCO 3 ) or
multiple regression equations may be used for predicting NEP. However,
(Si+S)/(C+CaCO3 ) is recommended for predicting NEP, and in all cases
the equivalent WE can be obtained from the standard table. A table for
wind erodibility groups was developed for the State.