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A Combined Salt Transport-Chemical Equilibrium Model for Calcareous and Gypsiferous Soils

Robbins, C.W. and Wagenet, R.J. and Jurinak, J.J. (1980) A Combined Salt Transport-Chemical Equilibrium Model for Calcareous and Gypsiferous Soils. Soil Science Society of America Journal. 44:1191-1194.

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Abstract

Chemical precipitation-dissolution and cation exchange subroutines
were interfaced with an existing water movement-salt
transport model. Three model options available for testing the
prediction of salt transport and storage were (i) individual ion
transport without soil interaction, (ii) precipitation and dissolution
of lime and gypsum during transport, and (iii) cation
exchange in addition to the precipitation-dissolution reactions.
The transport model also predicts relative crop growth and
water uptake as affected by soil moisture and salinity. The
chemical subroutine used by the second and third options calculated
ionic activities, corrected for ionic strength and ion
pair formation, and was used to calculate lime and gypsum
precipitation and dissolution. Cation activities were also used
to calculate Ca, Mg, Na, and K exchange equilibria by a method
that allows for addition of any number of exchangeable cations.
Values predicted by the three options for EC, SAR and Ca,
Mg, Na, A, Cl, SO? and HCO? concentrations were compared
to experimental data obtained from a lysimeter study and were
only satisfactorily predicted when both chemical precipitations
and cation exchange were considered for a gypsiferous and a
nongypsiferous soil irrigated with a high, medium, and low
CaSO? water at two leaching fractions.

Item Type: Article
NWISRL Publication Number: 0457
Subjects: Soil > Calcareous soil
Soil > Chemistry
Research methodology
Mass Import - autoclassified (may be erroneous)
Depositing User: Dan Stieneke
Date Deposited: 20 Nov 2010 21:52
Last Modified: 26 Jan 2017 18:05
Item ID: 372
URI: https://eprints.nwisrl.ars.usda.gov/id/eprint/372