Comparing Hydric Erosion Soil Loss Models in Rainy Mountainous and Dry Flat Regions in Portugal

Lia Duarte,Ana Cláudia Teodoro,Mário Cunha

doi:10.3390/land10060554

Lia Duarte, Ana Cláudia Teodoro + Show 1 more

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https://doi.org/10.3390/land10060554

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Abstract

Soil erosion is a severe and complex issue in the agriculture area. The main objective of this study was to assess the soil loss in two regions, testing different methodologies and combining different factors of the Revised Universal Soil Loss Equation (RUSLE) based on Geographical Information Systems (GIS). To provide the methodologies to other users, a GIS open-source application was developed. The RUSLE equation was applied with the variation of some factors that compose it, namely the slope length and slope steepness (LS) factor and practices factor (P), but also with the use of different sources of information. Eight different erosion models (M1 to M8) were applied to the two regions with different ecological conditions: Montalegre (rainy-mountainous) and Alentejo (dry-flat), both in Portugal, to compare them and to evaluate the soil loss for 3 potential erosion levels: 0–25, 25–50 and >50 ton/ha·year. Regarding the methodologies, in both regions the behavior is similar, indicating that the M5 and M6 methodologies can be more conservative than the others (M1, M2, M3, M4 and M8), which present very consistent values in all classes of soil loss and for both regions. All methodologies were implemented in a GIS application, which is free and available under QGIS software.

Highlights

The areas with a high risk of soil water erosion were delimited based on the identification of potential soil erosion, through the application of Equation (2), which considers the factors of soil erosivity (R), soil erodibility (K), slope length and steepness (LS), and practices used for erosion control (P) translated into the expression: A = R × K × length and slope steepness (LS) × P
The different methodologies were applied to each study area to compare them, to evaluate and answer the question “which methodology is more appropriate to study the soil erosion risk in a mountainous and rainy zone such as Montalegre municipality and, on the other hand, which methodology is more appropriate for a dry and flat zone such as Alentejo”?
The different methodologies were applied to each study area to compare them, to evaluate and answer the question “which methodology is more appropriate to study the soil erosion risk in a mountainous and rainy zone such as Montalegre municipality and, on the other hand, which methodology is more appropriate for a dry and flat zone such as Alentejo?”

Summary

Introduction

Publisher’s Note: MDPI stays neutral with regard to jurisdictional claims in published maps and institutional affiliations. Soil erosion is a severe and complex issue in the agricultural area, and can be defined as a process of detachment of particles that are transported or deposited in other areas by water or wind actions. The Food and Agriculture Organization of the United Nations (FAO) in its main report starts with “Soils are fundamental to life on Earth” [1], while other research indicates that erosion is endangering several areas such as natural resources, flooding and affecting water reservoirs [2,3]. It is fundamental to assess and control the dimension of erosion and its socio-economic and environmental impacts

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