Pass the salt please! From a review to a theorical framework for integrating salinization impacts in food LCA

Food LCA should include salinization. Salinization is a threat not only to arable land but also to freshwater resources. Nevertheless, salinization impacts have been rarely and partially included in LCA so far. First, a comprehensive overview of salinization mechanisms is presented and highlights its multiple causes, which affect soil and water, and ultimately human health, ecosystems and resources. Second, adopting the ILCD analysis grid, we analyzed the scientific relevance and accuracy of existing published methods addressing salinization in LCA. Although interesting, these seminal approaches are often incomplete with regards to both the salinization pathways they cover and their geographical validity. Third, we analyzed how to consistently integrate salinization within the methodological frameworks for impacts modeling in LCA, and raised questions to address towards a comprehensive integration of salinization. (Résumé d'auteur

Sensitivity of Dar Es Salaam coastal aquifer to climate change with regard to seawater intrusion and groundwater availability

This paper presents the initial results of three years of investigation activities, carried on in the Dar es Salaam coastal plain (Tanzania) by the Adapting to Climate Change in Coastal Dar es Salaam (ACC-DAR) project, a cofounded research project, granted by the European Union, led by the Sapienza, University of Rome, in cooperation with Ardhi University of Dar es Salaam. The ACC-DAR project activities will enhance the capacities of Dar’s municipalities by increasing their understanding of adaptation practices, and by developing methodologies for integrating adaptation activities into strategies and plans for Urban Development and Environment Management (UDEM) in unplanned and unserviced coastal settlements. In order to provide a series of enhanced methodologies for improving municipal activities related to climate change (CC) issues in the water management sector, the specific environmental phenomenon of seawater intrusion was investigated. This phenomenon is already contributing, and will increasingly contribute as CC progresses, to the degradation of those natural resources on which a large part of Dar es Salaam’s peri-urban livelihoods depends. The target of this study was to investigate groundwater availability changes in Dar es Salaam’s coastal aquifer as a consequence of seawater intrusion and urbanization processes in the framework of CC effects, with the aim to set up an integrated approach to evaluate CC effects on groundwater resources in coastal plains affected by seawater intrusion, and to better manage these important natural resources. As such, geological and hydrogeological characterization of the area is part of the study, as lithological properties of outcropping geological formations and their main hydrogeological settings, as well as chemical groundwater characterization also depend on them, but they were not the target of the study

Stochastic modeling of soil salinity

A minimalist stochastic model of primary soil salinity is proposed, in which the rate of soil salinization is determined by the balance between dry and wet salt deposition and the intermittent leaching events caused by rainfall events. The long term probability density functions of salt mass and concentration are found by reducing the coupled soil moisture and salt mass balance equation to a single stochastic differential equation driven by multiplicative Poisson noise. The novel analytical solutions provide insight on the interplay of the main soil, plant and climate parameters responsible for long-term soil salinization. In particular, they show the existence of two distinct regimes, one where the mean salt mass remains nearly constant (or decreases) with increasing rainfall frequency, and another where mean salt content increases markedly with increasing rainfall frequency. As a result, relatively small reductions of rainfall in drier climates may entail dramatic shifts in long-term soil salinization trends, with significant consequences e.g. for climate change impacts on rain-fed agricultur

Water reuse for irrigated agriculture in Jordan: challenges of soil sustainability and the role of management strategies

Reclaimed water provides an important contribution to the water balance in water-scarce Jordan, but the quality of this water presents both benefits and challenges. Careful management of reclaimed water is required to maximize the nutrient benefits while minimizing the salinity risks. This work uses a multi-disciplinary research approach to show that soil response to irrigation with reclaimed water is a function of the management strategies adopted on the farm by the water user. The adoption of management methods to maintain soil productivity can be seen to be a result of farmers’ awareness to potentially plant-toxic ions in the irrigation water (70% of Jordan Valley farmers identified salinization as a hazard from irrigation with reclaimed water). However, the work also suggests that farmers’ management capacity is affected by the institutional management of water. About a third (35%) of farmers in the Jordan Valley claimed that their ability to manage salinization was limited by water shortages. Organizational interviews revealed that institutional awareness of soil management challenges was quite high (34% of interviewees described salinization as a risk from water reuse), but strategies to address this challenge at the institutional level require greater development

Bordos and Boundaries: Sustainable Agriculture in the High Altitude Deserts of Northwest Argentina, AD 850-1532

Bordos were essential for the long-term sustainability of agriculture in the high altitude desert of Antofagasta de la Sierra in Northwest Argentina during the Late (AD 850 – 1480) and Inca Period (AD 1480 – 1532). Bordos were lineal humps of soil that stimulated the pedogenesis of the predominantly sandy soils of the area. Furthermore, they served as boundaries delimiting irrigation and cultivation fields. Therefore, bordos alongside other technologies were an efficient means by which viable farming was possible in an otherwise marginal agricultural zone. Besides explaining the role of bordos in the context of Northwestern Argentine agriculture this article describes the irrigation systems in place at Antofagasta de la Sierra throughout this period and compares it to the present state of affairs. Our results demonstrate that these late Prehispanic bordos and irrigation networks were well set out and organized such that use of water and soil was efficient, proportional and fair. The Inca do not seem to have disrupted these systems or local autonomy over them. In contrast, modern water and soil is characterized by a household-level decentralized management system. This situation leads to serious conflicts over water use allocations, wastage and flawed irrigation resulting in rising ground salinization.Fil: Salminci, Pedro Miguel. Secretaría de Cultura de la Nación. Dirección Nacional de Cultura y Museos. Instituto Nacional de Antropología y Pensamiento Latinoamericano; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Tchilinguirian, Pablo. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. University of Cambridge. Faculty of Archaeology and Anthropology; Reino UnidoFil: Lane, Kevin John. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. University of Cambridge. Faculty of Archaeology and Anthropology; Reino Unid

A Methodological Approach for Assessing Soil Salinity Hazard in Irrigated Areas. Case Study: The rut Irrigation District, Colombia

Se desarrolló una metodología para la evaluación y mapeo de la amenaza de salinización de suelos en distritos de riego de Colombia, con base en la concentración y tipo de sales en el agua de riego. La evaluación inició con la identificación de áreas de riego y la caracterización de sus parámetros fisicoquímicos. Esta caracterización permitió, por un lado, conocer la concentración de sales a través de la CEw, y por otro, estimar los tipos de sales presentes empleando el modelo Sosalriego. Luego, se asignaron niveles de amenaza en cada zona de riego, los cuales fueron espacializados empleando SIG. Finalmente, la aplicación del modelo permitió priorizar y orientar acciones de manejo para cada nivel de peligro identificados en el caso de estudio.A methodology towards assessing soil salinity hazard at irrigated areas of Colombia was developed based on both electrical conductivity and solubility of salts in water. First, irrigated areas were identified; and then, their physicochemical parameters were determined for characterizing electrical conductivity of water (ECw) as well as predicting salt contents in water by employing the Solsariego model. Afterwards, levels of salinity hazard were assessed by matching classes of ECw and solubility of salts in water. Finally, the salinity hazard was mapped for each irrigated zone. As a major conclusion, we consider that the methodological approach based on water quality assessment (ECw, salt contents, and their solubility in the irrigated water) allowed to prioritize hazard level. Hence, we can address activities for managing the soil salinity in the case study

Extent of Salt Affected Land in Central Asia: Biosaline Agriculture and Utilization of the Salt-affected Resources

The current status and trends of salinization are discussed with waterlogging of marginal land/plant and water resources problems including strategies for development of integrated biosaline crop-livestock agriculture based system on food-feed crops and forage legumes for better livelihood of poor farmers in Central Asian (Uzbekistan, Kazakhstan, Turkmenistan and Tajikistan). Transfer of technologies and/or methodology of ICBA (International Centre for Biosaline Agriculture) in planting of both perennial and annual valuable halophytes (based on around the world dataset from similar sites and conditions) are a new approach that should be tested in Central Asia. Afforestation, as an option to mitigate land degradation, requires a judicious evaluation and selection of multipurpose tree species (MPTS) to make use of marginal unproductive/salt- affected lands and lower the elevated groundwater table (GWT) via biodrainage. The leading among 21 screened native and introduced tree and shrubs species with regards to survival rate, growth characteristics and adaptability to high saline natural environment proved to be Haloxylon apphyllum, Salsola paletzkiana, S. richteri at the saline sandy deserts, followed by atriplex undulate, Hippophae ramnoides, E. angustifolia, Acacia ampliceps, U. pumila, P. euphratica and P. nigra var. pyramidalis, Robinia pseudoacacia, M. alba, Morus nigra on clay loamy hyromorphic soils, whereas fruit species such as Cynadon oblonga, Armeniaca vulgare, Prunus armeniaca and species of genera Malus, though desirable from the farmer's financial viewpoint, showed low bio drainage potential. Planting herbaceous fodder crops within the inter-spaces of fodder salt tolerant trees and shrubs on intensive agro-forestry plantations could solve the animal feeding problem in the degraded (both by overgrazing and salinity) desert and semidesert marginal areas. Yield data of new varieties of sorghum and pearl millet ICBA/ICRISAT germplasm collected at the conclusion of the 2006-2007 growing seasons indicates considerable adaptability of introduced genetic material to saline soil conditions, when compared to local material. Sorghum and pearl millet crop residues utilization could be an option for bio fuel production in the region.

Implications of land and water degradation on food security

Land degradation / Erosion / Water pollution / Sedimentation / Groundwater depletion / Salt water intrusion / Soil salinity / Urbanization / Wetlands