 |
| Titel |
Use of magnetic iron oxide to determine soil losses in rainfed olive orchard plots |
| VerfasserIn |
G. Guzman, J. A. Gómez, J. V. Giráldez |
| Konferenz |
EGU General Assembly 2012
|
| Medientyp |
Artikel
|
| Sprache |
Englisch
|
| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 14 (2012) |
| Datensatznummer |
250062208
|
|
|
|
|
|
| Zusammenfassung |
| Soil erosion is a major threat for sustainability of olive cropped areas in Mediterranean
countries, like southern Spain where ~17% of its surface is covered by olive orchards
(Gómez et al. 2005). Despite the large number of research dedicated to the study of
soil erosion in olive orchards, a significant uncertainty persists in the estimation of
actual erosion rates in these areas (Gómez et al. 2008; Fleskens and Stroosnijder,
2007). Due to the technical and economic limitations of traditional methods used in
erosion measurement, there is a growing interest in the use of new methods including
tracking of soil incorporating tracers in experiments performed at different scales and
time periods. Magnetic iron oxide particles are good tracers to complement, or
even replace traditional techniques of soil loss measurement after rainfall events
under controlled rainfall conditions, especially at the small scale (Guzmán et al.
2010).
From October 2008 to August 2010 soil losses were measured in two olive orchard runoff
plots. During that period magnetic iron oxide concentration changes were also determined to
estimate total soil losses and soil redistribution by water and tillage erosion in the plots,
differentiating between the inter-tree rows, tree rows and rill areas influence. Average
measured and estimated soil losses in the plots were 14.1 and 14.2 kg-
m-2 respectively.
Magnetic iron oxide as a sediment tracer allowed the estimation of soil losses with a
RSME of 0.72 kg-
m-2. Although soil erosion rates from tree rows were lower (0.6
kg-
m-2-
month-1) compared to inter-tree row rates (1.1 kg-
m-2-
month-1), the contribution
of tree row areas to total soil losses was considerably high because of the great volume of the
tree canopies in the plots and therefore, covered area (53.5 %). Magnetite content
variations both overland and within the soil profile, selectivity of the tracer for
finer soil particles, and soil bulk density changes, due to tillage-compaction and
swelling-shrinking processes were the key factors for the precision of the estimation
of soil losses. Detachment and erosion areas were identified in the plots through
changes of iron oxide content in the soil. This study indicates that magnetic iron
oxide can be a useful method to assess the suitability of different olive orchard
management methods and to monitor sediment dynamics at a similar scale to that of
the studied plots, albeit controlling with great care the factors identified in this
study.
References:
Fleskens, L., Stroosnijder, L. 2007. Is soil erosion in olive groves as bad as often claimed?
Geoderma 141: 260–271.
Gómez, J.A., Giráldez, J.V., Fereres, E. 2005. Water erosion in olive orchards in
Andalusia (Southern Spain): a review. European Geosciences Union. Geophys. Res. Abstr.
vol. 7, 08406.
Gómez, J.A., Giráldez, J.V., Vanwalleghem, T. 2008. Comments on “Is soil erosion in
olive groves as bad as often claimed?” by L. Fleskens and L. Stroosnijder. Geoderma 147:
93–95.
Guzmán, G., Barrón, V., Gómez, J.A. 2010. Evaluation of magnetic iron oxides as
sediment tracers in water erosion experiments. Catena 82: 126–133. |
|
|
|
|
|
|