Impact of soil water flux on vadoze zone solute transport parameters

2002 ◽  
Vol 33 (3-4) ◽  
pp. 479-492 ◽  
Author(s):  
Xiaomin Chen ◽  
M. Vanclooster ◽  
Genxing Pan
Keyword(s):  
Solute Transport ◽  
Soil Water ◽  
Water Flux ◽  
Transport Parameters ◽  
Vadoze Zone ◽  
Soil Water Flux

scholarly journals Measurement of soil water flux in andisols at a depth below a root zone of about 1 Meter

1994 ◽  
Vol 40 (1) ◽  
pp. 137-147 ◽  
Author(s):  
Shuichi Hasegawa ◽  
Seiko Osozawa ◽  
Hideto Ueno
Keyword(s):  
Soil Water ◽  
Root Zone ◽  
Water Flux ◽  
Soil Water Flux

scholarly journals Evaluation of DSSAT soil-water balance module under cropped and bare soil conditions

2003 ◽  
Vol 46 (4) ◽  
pp. 489-498 ◽  
Author(s):  
Rogério Teixeira de Faria ◽  
Walter Truman Bowen
Keyword(s):  
Soil Moisture ◽  
Water Balance ◽  
Soil Water ◽  
Water Flux ◽  
Soil Water Potential ◽  
Bare Soil ◽  
Root Water Uptake ◽  
Soil Water Balance ◽  
Soil Conditions ◽  
Soil Water Flux

The performance of the soil water balance module (SWBM) in the models of DSSAT v3.5 was evaluated against soil moisture data measured in bare soil and dry bean plots, in Paraná, southern Brazil. Under bare soil, the SWBM showed a low performance to simulate soil moisture profiles due to inadequacies of the method used to calculate unsaturated soil water flux. Improved estimates were achieved by modifying the SWBM with the use of Darcy's equation to simulate soil water flux as a function of soil water potential gradient between consecutive soil layers. When used to simulate water balance for the bean crop, the modified SWBM improved soil moisture estimation but underpredicted crop yield. Root water uptake data indicated that assumptions on the original method limited plant water extraction for the soil in the study area. This was corrected by replacing empirical coefficients with measured values of soil hydraulic conductivity at different depths.

scholarly journals Field and numerical study of chlorotoluron transport in the soil profile

2011 ◽  
Vol 50 (No. 8) ◽  
pp. 333-338 ◽  
Author(s):  
R. Kodešová ◽  
J. Kozák ◽  
O. Vacek
Keyword(s):  
Adsorption Isotherm ◽  
Solute Transport ◽  
Soil Water ◽  
Soil Profile ◽  
Preferential Flow ◽  
Water Movement ◽  
Numerical Study ◽  
Soil Samples ◽  
Transport Parameters ◽  
Four Square

The transport of chlorotoluron in the soil profile under field conditions was studied. The herbicide Syncuran was applied on a four square meter plot using an application rate of 2.5 kg/ha active ingredient. Soil samples were taken after 119 days to study the residual chlorotoluron distribution in the soil profile. HYDRUS-1D (Šimůnek et al. 1998) was used to simulate water movement and herbicide transport in the soil profile. Soil hydraulic properties and their variability were studied previously by Kutílek et al. (1989). The solute transport parameters, like the adsorption isotherm and the degradation rate, were determined in the laboratory. The Freundlich and Langmuir equations were used to fit the experimental data points of the adsorption isotherm, and the affect of each type of adsorption isotherm equation on the solute transport was studied. The chlorotoluron concentrations in soil water tended to be higher for the simulation performed with the Freundlich isotherm then that of the model using the Langmuir isotherm. In both cases, the solution did not pass a depth of8 cm. The simulated chlorotoluron concentrations in soil samples were higher then the observed concentrations when the chlorotoluron degradation was assumed to be in soil water only. Assumption of the solute degradation in both in the solid and the liquid phase significantly improved the accuracy of the solution. The different characters of the simulated and observed chlorotoluron distributions can probably be attributed to the preferential flow of water and solute in the soil profile and by variability of the transport parameters.

Automated In Situ Measurement of Unsaturated Soil Water Flux

1988 ◽  
Vol 52 (5) ◽  
pp. 1215-1218 ◽  
Author(s):  
J.J.M. van Grinsven ◽  
H.W.G. Booltink ◽  
C. Dirksen ◽  
N. van Breemen ◽  
N. Bongers ◽  
...  
Keyword(s):  
Soil Water ◽  
Unsaturated Soil ◽  
Water Flux ◽  
In Situ Measurement ◽  
Soil Water Flux
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