Medición y predicción de la erosión eólica en la región semiárida argentina
Wind erosion is an important soil degradation process of arid and semiarid environments. A 75% of Argentina is arid and semiarid. The quantification of wind erosion at field scale is lacking in the semiarid Pampas of Argentina (RSPC), making difficult the adjustment of wind erosion prediction models...
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Formato: | tesis doctoral |
Lenguaje: | Español |
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2009
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Acceso en línea: | http://repositoriodigital.uns.edu.ar/handle/123456789/1962 |
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I20-R126123456789-1962 |
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institution |
Universidad Nacional del Sur |
institution_str |
I-20 |
repository_str |
R-126 |
collection |
Repositorio Institucional Universidad Nacional del Sur (UNS) |
language |
Español |
orig_language_str_mv |
spa |
topic |
región semiárida erosión |
spellingShingle |
región semiárida erosión Mendez, Mariano Javier Medición y predicción de la erosión eólica en la región semiárida argentina |
topic_facet |
región semiárida erosión |
author2 |
Buschiazzo, Daniel Eduardo |
author_facet |
Buschiazzo, Daniel Eduardo Mendez, Mariano Javier |
format |
tesis doctoral |
author |
Mendez, Mariano Javier |
author_sort |
Mendez, Mariano Javier |
title |
Medición y predicción de la erosión eólica en la región semiárida argentina |
title_short |
Medición y predicción de la erosión eólica en la región semiárida argentina |
title_full |
Medición y predicción de la erosión eólica en la región semiárida argentina |
title_fullStr |
Medición y predicción de la erosión eólica en la región semiárida argentina |
title_full_unstemmed |
Medición y predicción de la erosión eólica en la región semiárida argentina |
title_sort |
medición y predicción de la erosión eólica en la región semiárida argentina |
publishDate |
2009 |
url |
http://repositoriodigital.uns.edu.ar/handle/123456789/1962 |
work_keys_str_mv |
AT mendezmarianojavier medicionypredicciondelaerosioneolicaenlaregionsemiaridaargentina |
bdutipo_str |
Repositorios |
_version_ |
1764820504901844992 |
description |
Wind erosion is an important soil degradation process of arid and semiarid environments. A 75% of Argentina is arid and semiarid. The quantification of wind erosion at field scale is lacking in the semiarid Pampas of Argentina (RSPC), making difficult the adjustment of wind erosion prediction models useful for the development of sustainable soil management practices. Soil coverage with plants is the most important variable for controlling wind erosion. The RWEQ relates the relative soil loss ratio (SLR, the quotient between the wind erosion amounts of a soil with plant coverage and the amount of erosion of a bare and smooth soil) with the percentage of soil coverage with laying (SLRf), and standing residues (SLRs) and plant canopy (SLRc). The RWEQ also calculates the evolution rate of SLR under different crops coverages as a function of the days after planting date. The relationships between SLR and soil coverage with vegetation were obtained with wind tunnels simulations. Little information is available on this issue for field conditions, particularly for Argentina.
The objective of this study was to validate the components of the VEGETATION subroutine of the Revised Wind Erosion Prediction System (RWEQ) for the RSPC, on the basis of field measurements of wind erosion. This study was carried out within the Experimental Field of the Facultad de Agronomía of the Universidad Nacional de La Pampa, on an Entic Haplustoll, during three years. Wind erosion was measured in the field with Big Spring Number Eight (BSNE) samplers. SLR was analyzed as a function of canopy and residues of wheat (Triticum aestivum), corn (Zea mays) and sunflower (Helianthus annus). Results showed that SLRf and the percentage of lying residues correlated in an exponential and negative way, in agreement with RWEQ equations. The coefficients of the equations obtained from field data were lower than those of RWEQ. Such differences were attributed to the lower wind velocities during field measurements than those considered by RWEQ. Own wind tunnel simulations with variable wind speeds confirmed this assumption.
SLRc also correlated exponentially and negatively with soil coverage with corn and sunflower canopies. Sunflower was slightly more efficient in controlling wind erosion than corn. This was attributed to their different leaves disposition in the space: planophyles on sunflower and erectophyles on corn. Though these small differences, the equation proposed by RWEQ was considered as adequate to predict SLR as a function of canopy of both crops in the RSPC.
The equation described adequately the evolution of coverage with wheat, corn and sunflower canopies (CC is the soil coverage with canopy, x the days after seeding, and a, b and c crop coefficients). The days until emergence of all crops were well described by the equation proposed by Andrade and Sadras (2002), which relates the accumulated daily temperature degrees (GDD) with the atmospheric and the soil temperature.
Measured SLRc was lower than the RWEQ-estimated SLRc during the first 25 days of corn growth. After this date this tendency reverted. These differences were attributed to the fastest corn growth in the RSPC, due to the highest soil temperatures than in US. The opposite tendency after day 25 was atributed to the best performance of hybrid corns used in US and to the more frequent water stresses occurred in the RSPC. SLRc was lower for corn than for sunflower during growth days 25 to 30 and higher after those dates. Such tendencies were attributed to the higher seeding density of corn which made this crop more effective in controlling wind erosion during early crop growth stages. The different leaves architecture (planophyle by sunflower and erechtophyle by corn) explained the differences in wind erosion control effectivity at advanced crops growth stages.
In aucence of water stress soil coverage with corn sunflower and Wheat canopies correlated with GDD during the first sexty days of crops grow. Wheat canopy of short cycle wheat was more effective in controlling wind erosion than the other wheat types during in early crop grow stages.
Lying and standing residues of corn and sunflower controlled less than 80% of the potential soil wind erosion while lying residues of wheat controlled more than 98%.
It can be deduced that in the study region, canopy and residues of winter small grain crops will be much more effective in controlling wind erosion than summer crops, particularly in the period of the year with higher climatic erosion risks, which extends from august to December. For this reason the inclusion of small grain winter crops in the rotations will be essentian for controlling wind erosion in this region. Residues of summer crops will be effective in controlling wind erosion only if they remain standing. Therefore, the regulation of harvest height and grazing intensity of these crops will be fundamental variables for an effective wind erosion control by these residues. |