Resumen

BEHRENDS KRAEMER, Filipe et al. Desplazamiento de la ganadería por la agricultura en una cuenca de La Pampa ondulada: Efectos sobre el escurrimiento superficial y erosión hídrica. Cienc. suelo [online]. 2013, vol.31, n.1, pp.83-92. ISSN 1850-2067.

The area under no-tillage in arable upland soils has been increasing since the 1990 decade in the Rolling Pampa. However, there is scarce information on soil use change and the adoption of no-tillage in fragile lowlands formerly devoted to pastures. The change from rangeland and pastures to soybean production may have promoted land degradation. This is why the possible consequences on runoff and sediment yield were estimated for the Tala basin (Buenos Aires, Argentina). The results show that cattle production was carried out mainly at the lowlands and thus the present analysis was focussed in that area of 138 km². Changes from annual cropping to pastures were negliglible while the opposite was verified in 2506 ha. These changes from pasture to cropping were observed mainly in the ecotone between upland soils and lowlands belonging to the valley. Also this change was more evident at the middle basin compared to the upper basin. Additional annual runoff volume of 250.000 a 500.000 m³ and 1100 t sediment yield was estimated as a consequence of this land use change. Owing to the proximity of these lands to the main water course, particularly the fragile soils from the middle basin it follows that physical and chemical water pollution (through nutients, fertilizers, pesticides) might have increased. In spite of the adoption of conservation practices like no tillage in the upland arable soils, the obtained results highlight some negative consequences regarding the «agriculturization» process that took place in some fragile lowlands from the study area.

Palabras clave : Land use; Agriculturization; GIS; Water erosion.

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