Articles | Volume 6, issue 2
https://doi.org/10.5194/se-6-383-2015
https://doi.org/10.5194/se-6-383-2015
Research article
 | 
09 Apr 2015
Research article |  | 09 Apr 2015

Spatial variability of soil properties and soil erodibility in the Alqueva reservoir watershed

V. Ferreira, T. Panagopoulos, R. Andrade, C. Guerrero, and L. Loures

Abstract. The aim of this work is to investigate how the spatial variability of soil properties and soil erodibility ($K$ factor) were affected by the changes in land use allowed by irrigation with water from a reservoir in a semiarid area. To this end, three areas representative of different land uses (agroforestry grassland, lucerne crop and olive orchard) were studied within a 900 ha farm. The interrelationships between variables were analyzed by multivariate techniques and extrapolated using geostatistics. The results confirmed differences between land uses for all properties analyzed, which was explained mainly by the existence of diverse management practices (tillage, fertilization and irrigation), vegetation cover and local soil characteristics. Soil organic matter, clay and nitrogen content decreased significantly, while the K factor increased with intensive cultivation. The HJ-Biplot methodology was used to represent the variation of soil erodibility properties grouped in land uses. Native grassland was the least correlated with the other land uses. The K factor demonstrated high correlation mainly with very fine sand and silt. The maps produced with geostatistics were crucial to understand the current spatial variability in the Alqueva region. Facing the intensification of land-use conversion, a sustainable management is needed to introduce protective measures to control soil erosion.

Download
Short summary
This study is on the spatial variability of soil properties and soil erodibility in the Alqueva reservoir, specifically regarding montado grassland land-use changes to more intensive and irrigated agriculture. Facing an intensification of land-use conversion will have an effect on soil erodibility and consequently increase the sedimentation into the reservoir and decrease its lifetime. Sustainable management is needed to introduce protective measures to control soil erosion.