Soil flooding

In neutral soils with smectite or vermiculite in the clay fractions, the changes in redox and bases status following soil flooding may cause synthesis of materials similar to smectite with Fe + in the octahedral sheet. Other cations, e.g. Zn +, may also become entrapped. 

Jackson MB, Armstrong W. 1999. Formation of aerenchyma and the processes of plant ventilation in relation to soil flooding and submergence. Plant Biology 1 274-287. 

Na > Li. Ionic concentration must also be taken into account, as these preferences can be overcome by high concentrations of an ion in soil solution. For example, sodium ions would dominate the exchange sites in soil flooded by seawater. 

Use of surfactants may prove to be a good technique for separating diesel fuel fit>m a soil as indicated in results obtained in preliminary screening tests (removal efficiencies up to 97%) and from results of other studies performed on laboratory-packed soil columns (removal efficiencies up to 8.6%), assuming flow through the bulk matrix. Results presented here using undisturbed, diesel-fuel-contaminated soil cores taken from a site indicate, however, that removal of diesel fuel from the soil flooded with surfactant solution was generally less than 1%. Low removal efficiencies in these soil... 

In continuously waterlogged soils, the low solubility of CdS results in low mobility. This fact can be used to advantage in severely contaminated soils to limit bioavailability. Well-drained soils polluted with Cd often allow hazardous levels of Cd uptake by crops the same soils flooded for rice production allow much less uptake by that crop. 

Effects of Reduction—Oxidation (Redox) Potential Yuita et al. (2005, 2006) determined concentrations of iodine naturally present in soil solutions of forest, upland, and paddy field soils of Japan. Despite seasonal fluctuations of iodine concentration in precipitation at the various sites, these workers found no seasonal variation in soil solution concentration of the forest and upland soils at any depth. However, at shallow depths in the paddy field soil, flood-irrigation conditions over the summer months induced a marked increase in iodine solution concentration (to around 50 ig-l ) when compared to pre-flood concentration (below 3 lg-l ). This was attributed to the low... 

Unflooded soil Flooded soil (Maahas clay) Flooded soil (Maahas clay) Paddy water (from Maahas clay) Paddy water (from Maahas clay)... 

The precipitation of phosphorus as calcium phosphate has been studied extensively by soil scientists in evaluating applied fertilizer reactions. Initial adsorption of phosphorus onto calcite is followed by precipitation as calcium phosphate. Similar reactions can occur at the soil-flood-water interface of calcareous wetlands. For example, long-term phosphorus accumulation in the Everglades marsh is linearly correlated with calcium accumulation, suggesting the possibility of phosphorus and CaCOj interactions (Reddy et al., 1993). 

Under aerobic conditions the remineralization of organic carbon by microbial action primarily results in the evolution of carbon dioxide. However, when soils flood for prolonged periods of time, oxygen and other inorganic electron acceptors are consumed. The microorganisms begin... 

Changes in soil redox properties, in particular due to soil flooding, may result in the dissolution and mobilisation of heavy metals from the polluted soils. 

Soils Flood site with plenty of cold water. Build barriers (dikes and lagoons) to contain large spills. Allow small spills to vaporize and absorb with sand or vermiculite. Use carbon dioxide foams to neutralize spills. 

The skin friction coefficient at the aquatic-sediment surface. This section provides means for obtaining numerical estimates of the coefficient of skin friction on the water-side of lengthy and flat soil or sediment surfaces positioned beneath a flowing water stream or bottom water marine current. The flowing water situations include surface streams, rivers, estuaries, shallow marine flows, flooded soils, flood plains, and so on. The Cf is then used with the appropriate analogy theory algorithm to obtain a numerical estimate of the water-side MTC. 

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