ISSN:
1432-1319
Source:
Springer Online Journal Archives 1860-2000
Topics:
Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
Notes:
Summary The steady-state leaching requirement (LR) model (USSL 1954) and the transient solute mass balance model of Rose et al. (1979) were applied to soil chloride data from 42 sites in Queensland, Australia, to evaluate utility of the models for assessing the impact of irrigation on soil salinity and leaching. Data were taken from previous studies on salinity in irrigated soils, and covered a wide range of soil types and irrigation managements. The time taken for soil chloride levels to reach steady-state was assessed from the transient model, and was calculated to be years (〉 3) or decades. These calculations showed that 19 sites had been sampled prior to steady-state, so that a strict application of the LR model was invalid. However, at only seven of these sites were there significant differences between sampled soil chloride and the calculated final values. At these seven sites leaching fluxes calculated with the two models differed by 3–162 mm y−1. At two sites leaching fluxes were ≤0 and the LR model could not be used to interpret soil chloride dynamics. Although both models assume constant inputs through time, variations in irrigation management practices at most sites had little practical effect on model predictions. However, where there were extreme variations in irrigation application or irrigation water chloride concentration, calculated leaching fluxes and thus predicted chloride levels were markedly affected. These models should not be applied in this situation. The transient model was preferred to the steady-state LR model for assessing the effect of irrigation on soil salinity, because of its ability to provide predictions of future soil chloride levels under non-steady conditions, and where leaching flux values are ≤ 0.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00190534
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