Search

It is well known that rainfall causes soil erosion in sloping German vineyards, but little is known about the effect of age of plantation on soil erosion, which is relevant to understand and design sustainable management systems. In the Ruwer-Mosel valley, young (1- to 4-years) and old (35- to 38-years after the plantation) vineyards were selected to assess soil and water losses by using two-paired Gerlach troughs over three years (2013-2015). In the young vineyard, the overland flow was 107 L m-1 and soil loss 1000 g m-1 in the year of the plantation, and decreased drastically over the two subsequent years (19 L m-1; 428 g m-1). In the old vineyard, soil (from 1081 g m-1 to 1308 g m-1) and water (from 67 L m-1 to 102 L m-1) losses were 1.2 and 1.63 times higher, respectively, than in the young vineyard.

All technosols belong to slightly alkaline substrates, with the exception of dark gray shale clay (pH 6.6). The concentration of soluble salts and manganese was the highest in the dark gray schist clay. The humus content does not exceed 1.4% in the phytomeliorated rocks. It was established that phyrtomelioration led to change intensity of reflectance of loess like loam from 0.6 to 0.53. The presence of fossil carbon was reflected in the spectrum of dark gray schist clay. The interpretation of VIS-NIR spectra of overburdened rocks should be done taking into account their geological age, formation and the stage of phytomelioration. [ABSTRACT FROM AUTHOR]

Copyright of Boletín de la Asociación de Geógrafos Españoles is the property of Asociacion de Geografos Espanoles and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Abstract: Many areas from the Mediterranean region are characterised by steep slope gradient, patchy vegetation cover and soil surface conditions prone to overland flow generation and sediment transport. This study evaluated the hydrological and sediment connectivity between sections (top, middle and bottom‐channel) from three low pressure grazed hillslopes located under contrasted Mediterranean climatic conditions in southern Spain. The aim was performed by installing rain‐gauge stations and opened‐plots in order to register overland flow and sediment concentration from February 2008 to January 2010. The results indicated that (i) major volumes of overland flow and sediment transport occurred more frequently in the humid and semiarid; (ii) the more frequent hydrological connectivity was observed between the middle and bottom‐channel sections, although the major values of overland flow and sediment concentration were registered in the upper sections; (iii) it was found very frequent those rainfall events in which all sections contributed with overland flow and sediment to the channel; (iv) the factors controlling hydrological and sediment connectivity varied from one site to another depending on the rainfall regime and vegetation cover, although the soil surface conditions (rock fragment cover either embedded or not embedded, crusts, annual plants, among others) were found as a key factor in all of them. In summary, the grazing activity, even being of low pressure, contributes to distance the hydrological and sediment connectivity from the response expected in the field sites, especially in that of humid Mediterranean climate: more overland flow and less sediment concentration and, vice versa, when becomes arid. Copyright © 2017 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Mediterranean mountains are facing great environmental and socioeconomic challenges in the current framework of Global Change. One of these is soil degradation, which is one of the major threats in those territories. Soil degradation is more dramatic where eco-geomorphology and land uses with less vegetation cover promote soil erosion. Soil erosion is influenced by soil erodibility, which can be assessed by different methodologies, e.g. RUSLE K factor and aggregate stability of soils. This study deals with the validation of RUSLE K factor by means of soil aggregate stability analysed in two-contrasted watersheds from one Mediterranean mountainous region in South of Spain, under sub-humid and semiarid climatic conditions. In both of them, landscape dynamic from 1956 to 2016 was analysed in order to characterize the modifications in land uses. A total of 361-soil samples was also taken covering all land uses for analysing aggregate stability of soils as well as those soil properties needed to calculate the RUSLE K factor. The results indicated that: i) landscape dynamic was influenced by changes in land uses contributing mainly to an increment in vegetation cover in the rainiest watershed; ii) the analysed soil properties showed very few significant differences between watersheds and between land uses, especially regarding organic matter content; and iii) the validation of K Factor using aggregate stability was better in the rainiest watershed and, within this one, in the natural land uses and irrigated cultivations, meaning where the biotic factors were more influential. These results implicated more researches are necessary, principally, focussed on the validation of the RUSLE K parameter using different fractions of aggregates as well as considering other eco-geomorphological parameters. • Two watersheds differing in climate and eco-geomorphology were analysed. • Land use changes were characterized from 1956 to 2016. • Aggregate stability and K Factor were calculated to assess soil erodibility. • K Factor was validated by comparison with aggregate stability. • Validation results were better achieved in the sub-humid watershed. [ABSTRACT FROM AUTHOR]