Maîtrise de la salinité

Résumé

vignette|250px|Modélisation numérique avec le logiciel SegReg : production de grains de moutarde en fonction de la salinité du sol. Le contrôle de la salinité permet de préserver le potentiel d'un sol, essentiellement en vue de son exploitation agricole. De façon préventive, il permet de limiter la dégradation par excès de sels et de restaurer des sols comportant des éléments chimiques en excès quelle qu'en soit l'origine . On parle aussi d'amélioration, de remédiation ou de récupération des sols. L'eau de pluie généralement acide ainsi que l'eau d'irrigation peut mettre en solution des éléments constitutifs des roches du sol ou sous-sol. Dans les régions arides, ces éléments ne sont pas lessivés et s'accumulent provoquant la salinisation. Celle-ci peut être aggravée par des apports d'engrais inadaptés. La première cause anthropique de salinisation est l'irrigation, car l'eau d'irrigation, qu'il s'agisse d'eau de ruissellement ou d'infiltration, surtout en région aride, transporte un

Source officielle

https://fr.wikipedia.org/wiki/Ma%C3%AEtrise_de_la_salinit%C3%A9

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Séances de cours associées (5)

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Kinetics of xylem loading, membrane potential maintenance, and sensitivity of K+-permeable channels to reactive oxygen species: physiological traits that differentiate salinity tolerance between pea and barley

Amandine Massart

Salt sensitive (pea) and salt tolerant (barley) species were used to understand the physiological basis of differential salinity tolerance in crops. Pea plants were much more efficient in restoring otherwise depolarized membrane potential thereby effectively decreasing K+ efflux through depolarization-activated outward rectifying potassium channels. At the same time, pea root apex was 10-fold more sensitive to physiologically relevant H2O2 concentration and accumulated larger amounts of H2O2 under saline conditions. This resulted in a rapid loss of cell viability in the pea root apex. Barley plants rapidly loaded Na+ into the xylem; this increase was only transient, and xylem and leaf Na+ concentration remained at a steady level for weeks. On the contrary, pea plants restricted xylem Na+ loading during the first few days of treatment but failed to prevent shoot Na+ elevation in the long term. It is concluded that superior salinity tolerance of barley plants compared with pea is conferred by at least three different mechanisms: (1) efficient control of xylem Na+ loading; (2) efficient control of H2O2 accumulation and reduced sensitivity of non-selective cation channels to H2O2 in the root apex; and (3) higher energy saving efficiency, with less ATP spent to maintain membrane potential under saline conditions.

Wiley-Blackwell2014

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Coastal reservoir contributes to alleviating the freshwater shortage in stressed areas, and the salinization of reservoir water is one of the most important challenges that coastal reservoir faced. Field-investigation indicates that there are many deep pools located at reservoir bed, and a large amount of high-salinity water was found within a deep pool which was hardly be desalted. Laboratory experiments and numerical simulations with different depth and locations of deep pools were conducted to further discuss the influence of deep pool on the salinization of reservoir and adjacent aquifer. Results showed that deep pool has greatly increased the salinity of reservoir water due to high-salinity water stored in the deep pool, which may act as an extra source of saltwater to the coastal reservoir during the dry season. The increasing depth of the deep pool was found to have negative impacts on the salinity of reservoir water, and as the distance from the deep pools to dam increased, the salinization extent in coastal reservoir decreased. Salinity data from the numerical simulations in coastal reservoirs and adjacent aquifer were matched the experimental data well. Flow field indicates that there is a high exchange capacity zone occurred from the deep pool to the seaward boundary, which gave the reasonable reasons for the existence of high-salinity water within deep pools. Those findings highlight the significant influence of deep pool on the salinization of the coastal reservoir, and explain the increased salinization by the deep pool.

2019

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Applicability of a general effective stress concept to unsaturated soils

2000

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