Ecological interactions, feedbacks, thresholds and collapses in the Argentine Pampas in response to climate and farming during the last century

Viglizzo, Ernesto F.; Frank, Federico C.

doi:10.1016/j.quaint.2006.05.022

Cited by 84 publications

(82 citation statements)

References 11 publications

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“…Paired woodland and agriculture sites (DF1-AG1, DF3-AG5/6, DF4-AG7, and DF5-AG8) with similar geological and geomorphological traits were used for adjacent comparisons. All selected agricultural sites were unirrigated and were subject to typical crop rotations of the region, primarily a combination of annual crops such as corn, sunflower, wheat, and soybean since the 1990s and alfalfa pastures and annual forage grasses during the 1980s and before (Viglizzo and Frank 2006). The only fertilizer applied in crop fields is nitrogen, mostly in the form of urea and typically at rates ,100 kgÁha À1 Áyr À1 .…”

Section: Site Selectionmentioning

confidence: 99%

Changes in hydrology and salinity accompanying a century of agricultural conversion in Argentina

Jayawickreme

Santoni

Kim

et al. 2011

Ecological Applications

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Abstract. Conversions of natural woodlands to agriculture can alter the hydrologic balance, aquifer recharge, and salinity of soils and groundwater in ways that influence productivity and sustainable land use. Using a land-use change chronosequence in semiarid woodlands of Argentina's Espinal province, we examined the distribution of moisture and solutes and estimated recharge rates on adjacent plots of native woodlands and rain-fed agriculture converted 6-90 years previously. Soil coring and geoelectrical profiling confirmed the presence of spatially extensive salt accumulations in dry woodlands and pervasive salt losses in areas converted to agriculture. A 1.1-km-long electrical resistivity transect traversing woodland, 70-year-old agriculture, and woodland, for instance, revealed a low-resistivity (high-salinity) horizon between ;3 m and 13 m depth in the woodlands that was virtually absent in the agricultural site because of leaching. Nine-meter-deep soil profiles indicated a 53% increase in soil water storage after 30 or more years of cultivation. Conservative groundwater-recharge estimates based on chloride tracer methods in agricultural plots ranged from ;12 to 45 mm/yr, a substantial increase from the ,1 mm/yr recharge in dry woodlands. The onset of deep soil moisture drainage and increased recharge led to .95% loss of sulfate and chloride ions from the shallow vadose zone in most agriculture plots. These losses correspond to over 100 Mg of sulfate and chloride salts potentially released to the region's groundwater aquifers through time with each hectare of deforestation, including a capacity to increase groundwater salinity to .4000 mg/L from these ions alone. Similarities between our findings and those of the dryland salinity problems of deforested woodlands in Australia suggest an important warning about the potential ecohydrological risks brought by the current wave of deforestation in the Espinal and other regions of South America and the world.

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Section: Site Selectionmentioning

confidence: 99%

Changes in hydrology and salinity accompanying a century of agricultural conversion in Argentina

Jayawickreme

Santoni

Kim

et al. 2011

Ecological Applications

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“…The strong wetting in this region has had a significant economic impact, owing to the subsequent expansion of its agricultural frontiers (Viglizzo et al 2006;Barros et al 2008). Understanding the causes of the recent wetting, therefore, is a question of major importance.…”

Section: Introductionmentioning

confidence: 99%

Stratospheric ozone depletion: a key driver of recent precipitation trends in South Eastern South America

et al. 2013

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On a hemispheric scale, it is now well established that stratospheric ozone depletion has been the principal driver of externally forced atmospheric circulation changes south of the Equator in the last decades of the 20th Century. The impact of ozone depletion has been felt over the entire hemisphere, as reflected in the poleward drift of the midlatitude jet, the southward expansion of the summertime Hadley cell and accompanying precipitation trends deep into the subtropics. On a regional scale, however, surface impacts directly attributable to ozone depletion have yet to be identified. In this paper we focus on South Eastern South America (SESA), a region that has exhibited one of the largest wetting trends during the 20th Century. We study the impact of ozone depletion on SESA precipitation using output from 6 different climate models, spanning a wide range of complexity. In all cases we contrast pairs of model integrations with and without ozone depletion, but with all other forcings identically specified. This allows for unambiguous attribution of the computed precipitation trends. All 6 climate models consistently reveal that stratospheric ozone depletion results in a significant wetting of SESA over the period 1960-1999. Taken as a whole, these model results strongly suggest that the impact of ozone depletion on SESA precipitation has been as large as, and quite possibly larger than, the one caused by increasing greenhouse gases over the same period.

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“…Extremely dry conditions produced cattle mortality, crop failure, farmer bankruptcy and rural migration (Viglizzo and Frank, 2006). Even during the wet period (after the 1970s), extended agricultural droughts altered sowing or critical crop growth periods decreasing yields (Minetti et al, 2007;2010).…”

Section: Decadal To Multidecadalmentioning

confidence: 99%

Interannual-to-multidecadal Hydroclimate Variability and its Sectoral Impacts in northeastern Argentina

Lovino¹,

Müller²,

Müller³

et al. 2018

Preprint

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Ecological interactions, feedbacks, thresholds and collapses in the Argentine Pampas in response to climate and farming during the last century

Cited by 84 publications

References 11 publications

Changes in hydrology and salinity accompanying a century of agricultural conversion in Argentina

Changes in hydrology and salinity accompanying a century of agricultural conversion in Argentina

Stratospheric ozone depletion: a key driver of recent precipitation trends in South Eastern South America

Interannual-to-multidecadal Hydroclimate Variability and its Sectoral Impacts in northeastern Argentina

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