SIMULTANEOUS INVERSE ESTIMATION OF SOIL HYDRAULIC AND SOLUTE TRANSPORT PARAMETERS FROM TRANSIENT FIELD EXPERIMENTS: HOMOGENEOUS SOIL

2003 ◽  
Vol 46 (4) ◽  
Author(s):  
F. Abbasi ◽  
J. Simunek ◽  
J. Feyen ◽  
M. Th. van Genuchten ◽  
P. J. Shouse
Keyword(s):  
Solute Transport ◽  
Field Experiments ◽  
Transient Field ◽  
Transport Parameters ◽  
Homogeneous Soil ◽  
Inverse Estimation ◽  
Soil Hydraulic

scholarly journals Measurement of Field Soil Hydraulic and Solute Transport Parameters

1998 ◽  
Vol 62 (5) ◽  
pp. 1172-1178 ◽  
Author(s):  
Francis X. M. Casey ◽  
Robert Horton ◽  
Sally D. Logsdon ◽  
Dan B. Jaynes
Keyword(s):  
Solute Transport ◽  
Field Soil ◽  
Transport Parameters ◽  
Soil Hydraulic

scholarly journals Field scale variability of solute transport parameters and related soil properties

1997 ◽  
Vol 1 (4) ◽  
pp. 801-811 ◽  
Author(s):  
B. Lennartz ◽  
S. K. Kamra ◽  
S. Meyer-Windel
Keyword(s):  
Soil Properties ◽  
Solute Transport ◽  
Water Content ◽  
Soil Water ◽  
Soil Water Content ◽  
Preferential Flow ◽  
Type I ◽  
Transport Parameters ◽  
Undisturbed Soil ◽  
Soil Hydraulic

Abstract. The spatial variability of transport parameters has to be taken into account for a reliable assessment of solute behaviour in natural field soils. Two field sites were studied by collecting 24 and 36 small undisturbed soil columns at an uniform grid of 15 m spacing. Displacement experiments were conducted in these columns with bromide traced water under unsaturated steady state transport conditions. Measured breakthrough curves (BTCs) were evaluated with the simple convective-dispersive equation (CDE). The solute mobility index (MI) calculated as the ratio of measured to fitted pore water velocity and the dispersion coefficient (D) were used to classify bromide breakthrough behaviour. Experimental BTCs were classified into two groups: type I curves expressed classical solute behaviour while type II curves were characterised by the occurrence of a bromide concentration maximum before 0.35 pore volumes of effluent (MI<0.35) resulting from preferential flow conditions. Six columns from site A and 8 from site B were identified as preferential. Frequency distributions of the transport parameters (MI and D) of both sites were either extremely skewed or bimodal. Log-transformation did not lead to a normal distribution in any case. Contour maps of bromide mass flux at certain time steps indicated the clustering of preferential flow regions at both sites. Differences in the extent of preferential flow between sites seemed to be governed by soil structure. Linear cross correlations among transport parameters and independently measured soil properties revealed relations between solute mobility and volumetric soil water content at time of sampling, texture and organic carbon content. The volumetric field soil water content, a simple measure characterising the soil hydraulic behaviour at the sampling location, was found to be a highly sensitive parameter with respect to solute mobility and preferential flow situations. Almost no relation was found between solute transport parameters and independently determined soil properties when non-preferential and preferential samples were considered separately in regression analyses. Future work should concentrate to relate integrated parameters such as the infiltration rate or the soil hydraulic functions to solute mobility under different flow situations.

scholarly journals Transect Scale Solute Transport Measured by Time Domain Reflectometry

2002 ◽  
Vol 33 (2-3) ◽  
pp. 145-164 ◽  
Author(s):  
Magnus Persson ◽  
Ronny Berndtsson
Keyword(s):  
Solute Transport ◽  
Mass Balance ◽  
Water Content ◽  
Time Domain ◽  
Field Experiments ◽  
Breakthrough Curves ◽  
Time Domain Reflectometry ◽  
Transport Parameters ◽  
Entire Experiment

Two quasi steady-state solute transport experiments were carried out in a loamy sand under field conditions. The flux was 40 mm/d in experiment 1 and 18.7 mm/d in experiment 2. Both water content (θ) and resident concentration (Cr) measurements were taken using 64 time domain reflectometry probes at depths ranging from 0.05 to 0.90 m. The Cr measurement was calibrated in situ for each probe location in the field. The convective dispersive equation (CDE) and convective lognormal transfer function (CLT) models were fitted to the breakthrough curves (BTCs). The results indicated fingered flow, which has been shown to exist in previous studies of this soil. The finger width was larger in experiment 1 leading to smaller horizontal heterogeneity and a relatively smaller solute transport velocity. The location of the fingers was consistent between the two experiments resulting in a high correlation between the velocity and mass balance fields. Mass balance calculations showed that the solute mass integrated over depth one day after the solute application was larger than the mass balance for the entire experiment (integrated over time). The probable reason being that solutes were transported out of the measurement volume by horizontal flow across the Ap/E horizon boundary. The investigation of the transport parameters revealed that both the CDE and CLT models could be successfully used to predict most individual BTCs. Horizontally averaged global CDE and CLT models were also fitted to the data. Global solute transport was better modeled with the CDE model in experiment 1, while in experiment 2, the CLT model was better. This study clearly shows the applicability of using TDR with the in situ calibration technique in field experiments with varying water content.

scholarly journals HYDRUS-2D Simulations of nitrate nitrogen and potassium transport characteristics under fertilizer solution infiltration of furrow irrigation

2020 ◽  
Author(s):  
Wei-Bo Nie ◽  
Kun-Kun Nie ◽  
Yi-Bo Li ◽  
Xiao-Yi Ma
Keyword(s):  
Solute Transport ◽  
Water Content ◽  
Nitrate Nitrogen ◽  
Sandy Loam ◽  
Furrow Irrigation ◽  
Distribution Range ◽  
Transport Parameters ◽  
Empirical Parameter ◽  
Vertical Range ◽  
Soil Hydraulic

Abstract Understanding the characteristics of soil solute transport is fundamental to the design and management of furrow irrigation systems. This study determined the soil hydraulic and solute transport parameters by inverse solution with HYDRUS-2D and then verified them. The experimental data were obtained from the infiltration of clay loam and sandy loam of different potassium nitrate (KNO3) concentrations under furrow irrigation. Then, the initial soil water content (θ0), KNO3 concentration, and water depth (h0) affecting the transport characteristics of nitrate nitrogen (NO3−-N) and potassium (K+) were analyzed. The results indicated that the soil hydraulic and solute transport parameters determined from the inversion solution with HYDRUS-2D were reliable. The soil saturated water content, saturated hydraulic conductivity, and empirical parameter n in the van Genuchten–Mualem model increase with the increase of KNO3 concentrations, whereas the empirical parameter a shows a decreasing tendency. The distribution range of NO3−-N increased with the increases of θ0 and the KNO3 concentration, which had barely any effect on the range of K+ distribution. The horizontal distribution range of NO3−-N and K+ increased with the increase of h0, but it had no obvious influence on the vertical range.

scholarly journals Inverse Estimation of Soil Hydraulic and Transport Parameters of Layered Soils from Water Stable Isotope and Lysimeter Data

2018 ◽  
Vol 17 (1) ◽  
pp. 170168 ◽  
Author(s):  
Jannis Groh ◽  
Christine Stumpp ◽  
Andreas Lücke ◽  
Thomas Pütz ◽  
Jan Vanderborght ◽  
...  
Keyword(s):  
Stable Isotope ◽  
Layered Soils ◽  
Transport Parameters ◽  
Water Stable Isotope ◽  
Inverse Estimation ◽  
Soil Hydraulic
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