Inexorable land degradation due to agriculture expansion in South American Pampa

Abstract

From 1985 onwards, South America has undergone a major expansion of agriculture at the expense of native vegetation (e.g. native Pampa grassland). As an emblematic crop, the surface area cultivated with soybeans has increased by 1000% between 1990 and 2020 in Uruguay. The environmental consequences of this massive land use conversion on soil degradation remain poorly documented although the agriculture expansion is projected to continue to increase in the coming years in South America. In this study, sediment cores were collected in reservoirs located downstream of two contrasted agricultural catchments draining the Rio Negro River (Uruguay) for reconstructing the sediment dynamics and the sources of erosion associated with this expansion.Results demonstrated the occurrence of two periods of acceleration of sediment delivery since the 1980s. The first period of acceleration was recorded in the mid-1990s and was related to afforestation programs. The second and larger acceleration phase was recorded after 2000 during the soybean crop expansion. This period has been marked by a greater supply of sediment from the native grassland source highlighting the impact of agriculture expansion at the expense of native vegetation. Conservation measures should therefore be urgently taken to preserve biodiversity and soil functions in this region.

Disproportionately High Contributions of 60 Year Old Weapons-137Cs Explain the Persistence of Radioactive Contamination in Bavarian Wild Boars

“…Nowadays, the baseline of airborne 137 Cs (<10 μBq·m –3 in Germany) contributes insignificantly to the relatively high inventory in soil 40 , 41 and consequently in wild boars. Considering that the above-mentioned contamination level is orders of magnitude greater than the 137 Cs inventories reported in less contaminated regions, 41 , 42 it suggests a substantial impact of Chornobyl- 137 Cs on the Bavarian ecosystem. This is consistent with reports of Chornobyl- 137 Cs dominating the total 137 Cs inventory in Austria by 90%.…”

Evaluación de riesgo y vulnerabilidad de montículos indígenas en contextos de producción agropecuaria en la región de India Muerta, Uruguay

“…La intensa actividad agrícola de la zona comprende grandes plantaciones de arroz y sorgo y, en menor medida, soja. Este tipo de producción en nuestro país, caracterizada por grandes monocultivos de especies genéticamente modificadas y asociada al uso extensivo de insumos químicos, generó importantes pérdidas de materia orgánica y alta degradación de suelos (Foucher et al, 2023), afectaciones que también se observan en los montículos. También es destacada la contaminación de aguas superficiales y subterráneas (Kruk et al, 2023), la pérdida de heterogeneidad ambiental y de biodiversidad (Gavier-Pizarro et al, 2012) y el impacto negativo en la estabilidad de los ecosistemas (Benton et al, 2003;Buhk et al, 2017).…”

“…La expansión e intensificación de la producción agrícola es uno de los factores que más afecta a la conservación de los bienes comunes, los ecosistemas, la biodiversidad y la diversidad cultural a nivel global (Hoekstra et al, 2005;Staude et al, 2018;Deák et al, 2021;Pörtner et al, 2022). Estas transformaciones se acrecentaron significativamente en la región de pastizales templados de Sudamérica en las últimas tres décadas (De Faccio Carvalho et al, 2021;Baeza et al, 2022;Ríos et al, 2022;Foucher et al, 2023). En los contextos rurales, la afectación y destrucción de sitios arqueológicos, conocidos y aún no descubiertos, avanza con la misma intensidad que el desarrollo de actividades agropecuarias (Reeder-Myers, 2015).…”

Navigating the Future through Experimental Policy Design

“…In particular, over the last 15 years, the country has witnessed a quadrupling of total grain production, driven by a twofold increase in productivity (tons/ha) and the expansion of agriculture into nontraditional areas. This expansion often encroaches upon the land with inadequate use capacity for intensive agriculture [32,33].…”