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

Abstract

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.

Evaluation of spatial distribution and regional zone delineation for micronutrients in a semiarid Deccan Plateau Region of India

“…Behera and Shukla () reported low (for pH and EC) to moderate (for SOC content) variability in Indian acid soils. Similarly, variability was low for pH and medium for EC and organic matter in soils of Alequeva reservoir of Portugal (Ferreira, Panagopoulos, Andrade, Guerrero, & Loures, ). In soils of northern Ethiopia, low (for pH) and medium variability (for SOC and available Fe) were reported (Tesfahunegn et al, ).…”

Quantifying the impact of land degradation on crop production: the case of Senegal

“…First, our available crop yield statistics refer to a spatial unit (polygons that combine land use and districts) for which the experts gave an assessment on degree and extent of land degradation but without more specific indication of where crops are cultivated, and where land degradation is prevalent. Second, there are various confounding factors at play that impact on both land degradation and crop production (Ferreira et al, 2015). Isolating these is especially difficult for Senegal because there are no historical records available on fertilizer application.…”

Spatial variability of some soil properties varies in oil palm (<i>Elaeis guineensis</i> Jacq.) plantations of west coastal area of India

“…According to Parfitt et al (2009), positive G values indicate that the map Skewness values of 0.18 to 3.89 for different soil proprieties revealed that some soil properties were not normally distributed. This variation and non-normal distribution of soil properties in the studied areas may be due to adoption of different soil management practices including variation in fertilizer application and other crop management practices (Tesfahunegn et al, 2011;Srinivasarao et al, 2014;Ferreira et al, 2015).…”