Spatial Variability Modeling of Soil Erodibility Index in Relation to Some Soil Properties at Field Scale

C Gyamfi,R.W Salim,J M Ndambuki

doi:10.5539/enrr.v6n2p16

Abstract

Soil erosion is a major land degradation issue affecting various facets of human lives. To curtail soil erosion occurrence requires understanding of soil properties and how they influence soil erosion. To this end, the soil erodibility index which gives an indication of the susceptibility of soils to erosion was examined. In particular, we aimed to determine soil erodibility index at field scale and establish relationships that exist between selected soil properties and soil erodibility index. It was hypothesized that for soil erodibility index to vary spatially, then the existing soil properties should have varying spatial structure. Hundred disturbed and 100 undisturbed soil samples were collected from a 7.3 ha gridded area. The samples were analyzed for particle size distribution, bulk density, particle density, organic matter content and porosity. All soil analyses were conducted following standard procedures. Data were analyzed statistically and geostatistically on the basis of semivariograms. Sandy clay loam was the dominant soil texture in the studied field. Results indicate significant negative relationship between sand content, bulk density, particle density and organic matter with soil erodibility index. Silt correlated significantly with a positive relation with soil erodibility. Estimated erodibility for the sampled field ranged from 0.019 t.ha.hr/ha.MJ.mmto 0.055 t.ha.hr/ha.MJ.mm. The order of dominance of erodibility ranges were 0.038-0.042 t.ha.hr/ha.MJ.mm&gt; 0. 036-0.08 t.ha.hr/ha.MJ.mm&gt; 0.032-0.036 t.ha.hr/ha.MJ.mm&gt; 0.019-0.032 t.ha.hr/ha.MJ.mm&gt; 0.042-0.055 t.ha.hr/ha.MJ.mm. Regression analysis revealed silt to be the most significant variable that influences soil erodibility. The best regression of soil properties on soil erodibility index gave an R2 of 0.90. A comparison of the regression equation with other studies indicated good performance of the equation developed.

Highlights

Land degradation through soil erosion is considered a natural and geologic phenomenon, and one of the most important components of the global geochemical cycle
Paramount to tackling the soil erosion menace is the need to take into cognizance the spatially distributed pattern and inherent variations caused by different land use management practices and varying soil types
We examined in this study soil erodibility index at field scale and established relations between soil properties and erodibility

Summary

Introduction

Land degradation through soil erosion is considered a natural and geologic phenomenon, and one of the most important components of the global geochemical cycle. Current increases in global demand for food and fresh water with its attendant land use changes exacerbate the menace of soil erosion with substantial consequences on soil and water resources sustainability. Paramount to tackling the soil erosion menace is the need to take into cognizance the spatially distributed pattern and inherent variations caused by different land use management practices and varying soil types. Other factors influencing the soil erosion process are rainfall and erosivity index, slope and length factor, cropping management factor and the practice factor and soil erodibility factor (Breetzke et al, 2013). Soil erodibility is considered an essential parameter among these factors since it governs the ease with which soils are detached. Due to the complex nature of erosion processes coupled with anthropogenic factors, it becomes truly essential to have up to date knowledge that is geared towards conservation www.ccsenet.org/enrr

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