The aims of this study were to (1) find critical areas susceptible to the degradation of natural resources according to local erosion rates and aridity levels, which were used as environmental quality indicators, and (2) identify areas of risk associated with the presence of natural hazards according to three climate change scenarios defined for Mexico. The focus was the municipality of Lerdo, Durango (25.166° to 25.783° N and 103.333° to 103.983° W), which has dry temperate and very dry climates (BSohw and BWhw). From the Global Circulation Models, downscaling techniques for the dynamic modeling of environmental processes using climate data, historical information, and three regionalized climate change scenarios were applied to determine the impacts from laminar wind erosion rates (LWER) and aridity indices (AI). From the historic period to scenario A2 (ScA2, 2010–2039), regarding greenhouse gas emissions, the LWER was predicted to reach 147.2 t ha−1 year−1, representing a 0.5 m thickness over nearly 30 years and a change in the AI from 9.3 to 8.7. This trend represents an increase in drought for 70.8 % of the study area and could affect 90 % of the agricultural activities and approximately 80 % of the population living in the southeastern Lerdense territory.

Los objetivos de la investigación fueron: 1) Evaluar los impactos probables del cambio climático (CC) en la agricultura de secano (AS) en Aguascalientes, México, con base en el modelo HadGEM2-ES para el forzamiento radiativo 8.5 en un futuro cercano, 2015-2039; y 2) Determinar la magnitud de los impactos del CC en la aptitud productiva de la AS a través del análisis de la variabilidad de la precipitación media anual (PMA). La unidad de estudio comprendió el territorio de Aguascalientes, cuyos climas predominantes son semiseco [BS1k w, BS1hw(w)] y templado subhúmedo [C(wO)], y PMA de 526 mm. La evaluación del impacto potencial del CC en la AS de Aguascalientes se basa en el análisis de características edáficas y topográficas en las cuales se practica esta actividad y se complementa con el análisis de la PMA para el futuro cercano, apoyados con imágenes satelitales tipo SPOT. Los resultados indican incrementos probables en la PMA del 20 %, lo cual no necesariamente garantiza un impacto positivo en la productividad del cultivo de maíz, ya que hay factores asociados a las condiciones edáficas, topográficas y de las políticas de uso de la tierra que determinan el éxito del mismo.

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<p>Calcareous soils are characterized by containing a greater amount inorganic carbon (SIC) than organic carbon (SOC), and both contribute to CO<sub>2</sub> emissions to the atmosphere. SOC mineralization and SIC dissolution are related to soil moisture content, but their effect on CO2 emissions from calcareous soils is unclear. This investigation aimed to evaluate the effect of moisture content on CO<sub>2</sub> emission of a calcareous soil in the Comarca Lagunera, Mexico.</p> <p>Calcareous soil samples were taken from a cropland and shrubland of Comarca Lagunera, Mexico and their physical and chemical properties were determined. For a 30-day period, 100g of soil were incubated in closed-jars and two moisture treatments, related to field capacity (FC) and permanent wilting point (PWP) values were applied. The CO<sub>2</sub> emission assessment was performed every two days using an infrared gas analyzer (IRGA, PP Systems, UK).</p> <p>For cropland, the FC, PWP, SIC and SOC values were 27.2 %, 14.6 %, 7.3 % (140.4 Mg ha<sup>-1</sup>) and 0.23 % (4.4 Mg ha<sup>-1</sup>), while for shrubland, the values were 27 %, 11 %, 7.6 % (152.8 Mg ha<sup>-1</sup>) and 0.08 % (1.6 Mg ha<sup>-1</sup>), respectively. Average emission of CO<sub>2</sub>, every two days, from cropland soil was 2.1 g CO<sub>2</sub> m<sup>-2</sup> h<sup>-1</sup> for moisture at FC, while to PWP was 1.7 g CO<sub>2</sub> m<sup>-2</sup> h<sup>-1</sup>, and for shrubland soil was 1.8 g CO<sub>2</sub> m<sup>-2</sup> h<sup>-1</sup> for moisture at FC, while to PWP was 1.6 g CO<sub>2</sub> m<sup>-2</sup> h<sup>-1</sup>.</p> <p>In both cases, cumulative CO<sub>2</sub> emissions were significantly higher in FC compared to PWP. For cropland, cumulative CO<sub>2</sub> emissions were 23.4 g CO<sub>2</sub> m<sup>-2</sup> h<sup>-1</sup> and 29.4 g CO<sub>2</sub> m<sup>-2</sup> h<sup>-1</sup>, but for shrubland were 21.7 g CO<sub>2</sub> m<sup>-2</sup> h<sup>-1</sup> and 25.3 g CO<sub>2</sub> m<sup>-2</sup> h<sup>-1</sup>. Cumulative CO<sub>2</sub> emissions for moisture content at FC were equivalent to a soil carbon (C) loss of 1.9 Mg ha<sup>-1</sup> and 1.7 Mg ha<sup>-1</sup> for cropland and shrubland, respectively. This result implies the loss of 43.2% (1.9 Mg C ha<sup>-1</sup> / 4.4 Mg SOC ha<sup>-1</sup>) of the SOC content in the cropland, but for the shrubland it suggests the total loss of the SOC (1.6 Mg C ha<sup>-1</sup> / 1.6 Mg SOC ha<sup>-1</sup>) and a part of the SIC content (0.1 Mg C ha<sup>-1 </sup>/ 152.8 Mg SIC ha<sup>-1</sup>).</p> <p>Our study shows that soil moisture content has a significant effect on CO<sub>2</sub> emissions from calcareous soils, such as Comarca Lagunera, where an increase in soil moisture corresponds to increases in CO<sub>2</sub> emissions into the atmosphere, where SIC and SOC reserves are involved.</p>