Transport of bromide in the Bainsvlei soil: Field experiment and deterministic/stochastic model simulation. II. Intermittent water application
Ketema Tilahun A C , J. F. Botha A and A. T. P. Bennie BA Institute for Groundwater Studies, The University of the Free State, PO Box 339, Bloemfontein 9300, Republic of South Africa.
B Department of Soil, Crop, and Climate Sciences, The University of the Free State, PO Box 339, Bloemfontein 9300, Republic of South Africa.
C Corresponding author. Present address: Alemaya University, PO Box 138, Dire Dawa, Ethiopia. Email: ketematilahun@yahoo.com
Australian Journal of Soil Research 43(1) 81-85 https://doi.org/10.1071/SR03015
Submitted: 29 January 2003 Accepted: 20 September 2004 Published: 14 February 2005
Abstract
Despite the fact that non-uniform soil water content and variable input water fluxes are usually encountered in the field, tracer experiments have usually been carried out under steady-state conditions. The objective of this study was to analyse solute transport in a Bainsvlei soil under intermittent water application using Br– as a tracer. Sprinkler was used to apply water on a plot 200 by 200 cm. Soil core samples were taken every 20 cm to a depth of 160 cm several times during the experiment.
The soil Br– concentration data were fitted to the steady-state convection–dispersion analytical model in the CXTFIT package. The average coefficients of determination yielded by this fit (r2 = 0.810) clearly support that the data could be analysed successfully with CXTFIT. The average pore-water velocity of 1.72 cm/day and average dispersion coefficient of 26.19 cm2/day determined from this fit are lower than the fitted values of the steady-state experiments. The Br– moved slower under the intermittent application of water than in the steady case, a conclusion supported by the deeper location of Br– peaks under continuous application than intermittent application after the same amount of water is applied.
Additional keywords: convection–dispersion equation, cumulative drainage, CXTFIT.
Beese F, Wierenga PJ
(1980) Solute transport through soil with adsorption and root water uptake computed with a transient and a constant flow model. Soil Science 129, 245–252.
Bowman RS, Rice RC
(1986) Transport of conservative tracers in the field under intermittent flood irrigation. Water Resources Research 22, 1531–1536.
Butters GL, Jury WA
(1989) Field scale transport of Br- in an unsaturated soil: 2. Dispersion modelling. Water Resources Research 25, 1583–1589.
Clothier BE, Green SR
(1994) Root zone processes and efficient use of irrigation water. Agricultural Water Management 25, 1–12.
| Crossref | GoogleScholarGoogle Scholar |
Jaynes DB, Rice RC
(1993) Transport of solutes as affected by irrigation method. Soil Science Society of America Journal 57, 1348–1353.
Jury WA,
Stolzy LH, Shouse P
(1982) A field test of the transfer function model for predicting solute transport. Water Resources Research 18, 369–375.
Kanchanasut P, Scotter DR
(1982) Leaching patterns in soil under pasture and crop. Australian Journal of Soil Research 20, 193–202.
McLay CDA,
Cameron KC, McLaren RG
(1991) Effect of time of application and continuity of rainfall on leaching of surface-applied nutrients. Australian Journal of Soil Research 29, 1–9.
Meyer-Windel S,
Lennartz B, Widmoser P
(1999) Bromide and herbicide transport under steady-state and transient flow conditions. European Journal of Soil Science 50, 23–33.
| Crossref | GoogleScholarGoogle Scholar |
Rawitz E, Burns S, Etkin H
(1980) Fate of fertilizer nitrogen in irrigated fields under semiarid conditions. ‘Soil nitrogen as fertiliser or pollutant. Proceedings and Report of a Research Coordination Meeting’. Piracicaba, 3–7 July 1978.. (International Atomic Energy Agency: Vienna)
Roth K,
Jury WA,
Fluhler H, Attimger W
(1991) Transport of chloride through unsaturated field soil. Water Resources Research 27, 2533–2541.
| Crossref | GoogleScholarGoogle Scholar |
Russo D,
Jury WA, Butters G
(1989) Numerical analysis of solute transport during transient irrigation. Water Resources Research 25, 2109–2118.
Sharma ML, Taniguchi M
(1991) Movement of a non-reactive solute tracer during steady and intermittent leaching. Journal of Hydrology 128, 323–334.
| Crossref | GoogleScholarGoogle Scholar |
Tilahun K,
Botha JF, Bennie ATP
(2005) Transport of bromide in the Bainsvlei soil: Field experiment and deterministic/stochastic model simulation I. Continuous water application. Australian Journal of Soil Research 43, 73–80.
Toride N, Leij FJ, van Genuchten M Th
(1995) The CXTFIT code for estimating transport parameters from laboratory and field tracer experiments. U.S. Salinity Laboratory Research Report No. 138, Riverside, CA.
Ward AL,
Kachanoski RG,
von Bertoldi AP, Elrick DE
(1995) Field and undisturbed column measurements for predicting transport in unsaturated layered soil. Soil Science Society of America Journal 59, 52–59.
White RE,
Dyson JS,
Gerstl Z, Yaron B
(1986) Leaching of herbicides through undisturbed cores of a structured clay soil. Soil Science Society of America Journal 50, 1050–1055.
Wierenga PJ
(1977) Solute distribution profiles computed with steady-state and transient water movement models. Soil Science Society of America Journal 41, 1050–1055.
Wild A, Babiker IA
(1976) The asymmetric leaching pattern of nitrate and chloride in a loamy sand under field conditions. Journal of Soil Science 27, 467–477.
