Runoff simulation sensitivity to remotely sensed initial soil water content

1994 ◽  
Vol 30 (5) ◽  
pp. 1393-1405 ◽  
Author(s):  
D. C. Goodrich ◽  
T. J. Schmugge ◽  
T. J. Jackson ◽  
C. L. Unkrich ◽  
T. O. Keefer ◽  
...  
Keyword(s):  
Water Content ◽  
Soil Water ◽  
Soil Water Content ◽  
Remotely Sensed ◽  
Runoff Simulation ◽  
Initial Soil

scholarly journals Preferential flow of surface‐applied solutes: Effect of lysimeter design and initial soil water content

2020 ◽  
Vol 19 (1) ◽  
Author(s):  
Mark R. Williams ◽  
Oscar Coronel ◽  
Scott J. McAfee ◽  
Laura L. Sanders
Keyword(s):  
Water Content ◽  
Soil Water ◽  
Soil Water Content ◽  
Preferential Flow ◽  
Initial Soil

scholarly journals Numerical Modeling of Water Movement from Buried Vertical Ceramic Pipes through Soils

2018 ◽  
Vol 24 (6) ◽  
pp. 72
Author(s):  
Zena Kamil Rasheed ◽  
Maysoon Basheer Abid
Keyword(s):  
Hydraulic Conductivity ◽  
Water Content ◽  
Soil Water ◽  
Soil Water Content ◽  
Transient Flow ◽  
Initial Conditions ◽  
Irrigation System ◽  
Pipe Length ◽  
Ceramic Pipe ◽  
Initial Soil

The problem of water scarcity is becoming common in many parts of the world, to overcome part of this problem proper management of water and an efficient irrigation system are needed.  Irrigation with a buried vertical ceramic pipe is known as a very effective in the management of irrigation water.  The two- dimensional transient flow of water from a buried vertical ceramic pipe through homogenous porous media is simulated numerically using the HYDRUS/2D software.  Different values of pipe lengths and hydraulic conductivity were selected.  In addition, different values of initial volumetric soil water content were assumed in this simulation as initial conditions.  Different values of the applied head were assumed in this simulation as boundary conditions.  The results of this research showed that greater spreading occurs in the horizontal direction.  Increasing applied heads, initial soil water contents and pipe hydraulic conductivities, cause increasing the size of wetting patterns but in a few increases.  Also, the results showed that the empirical formulas which can be used for expressing the wetted width and depth in terms of applied head, initial soil water content, application time, pipe hydraulic conductivity, and pipe length, are good and can be used as design equations.        

scholarly journals Numerical Modeling of Water Movement from Buried Vertical Ceramic Pipes through Coarse Soils

2018 ◽  
Vol 13 (4) ◽  
pp. 164-173
Author(s):  
Zena Kamil Rasheed ◽  
Maysoon Basheer Abid
Keyword(s):  
Hydraulic Conductivity ◽  
Water Content ◽  
Soil Water ◽  
Soil Water Content ◽  
Transient Flow ◽  
Vertical Direction ◽  
Empirical Formulas ◽  
Pipe Length ◽  
Ceramic Pipe ◽  
Initial Soil

Problem of water scarcity is becoming common in many parts of the world.  Thus to overcome this problem proper management of water and an efficient irrigation systems are needed.  Irrigation with buried vertical ceramic pipe is known as a very effective in management of irrigation water.  The two- dimensional transient flow of water from a buried vertical ceramic pipe through homogenous porous media is simulated numerically using the software HYDRUS/2D to predict empirical formulas that describe the predicted results accurately.   Different values of pipe lengths and hydraulic conductivity were selected.  In addition, different values of initial volumetric soil water content were assumed in this simulation as initial conditions.  Different values of applied head were assumed in this simulation as a boundary conditions.  In general, a good agreement was obtained when comparing the predicted results with available measured values.  The results of this research showed that greater spreading occur in vertical direction.  Increasing applied heads, initial soil water contents, pipe hydraulic conductivities, cause increasing the size of wetting patterns.  Also the results showed that the empirical formulas which can be used for expressing the wetted width and depth in terms of applied head, initial soil water content, application time, pipe hydraulic conductivity, and pipe length, are good and can be used as a designing equations.  

Effect of Initial Soil Water Content on Output Parameters of Sirmod Software Under Types of Different Irrigation Management

2019 ◽  
Vol 68 (4) ◽  
pp. 740-752
Author(s):  
Ali Javadi ◽  
Behrouz Mostafazadeh‐Fard ◽  
Mohammad Shayannejad ◽  
Hamed Ebrahimian
Keyword(s):  
Water Content ◽  
Soil Water ◽  
Soil Water Content ◽  
Irrigation Management ◽  
Initial Soil

scholarly journals Implications of Hysteresis on the Horizontal Soil Water Redistribution after Infiltration

Water ◽  
2021 ◽  
Vol 13 (19) ◽  
pp. 2773
Author(s):  
George Kargas ◽  
Konstantinos X. Soulis ◽  
Petros Kerkides
Keyword(s):  
Porous Medium ◽  
Hydraulic Conductivity ◽  
Water Content ◽  
Soil Water ◽  
Soil Water Content ◽  
Soil Matrix ◽  
Wetting And Drying ◽  
Initial Soil ◽  
Water Redistribution ◽  
Horizontal Infiltration

Although soil water redistribution is critical for a number of problems, a rather limited study of this process has been reported up to now and especially as regards the implications of hysteresis on horizontal soil water redistribution after infiltration. To this end, a thorough theoretical and numerical investigation of the redistributed soil water content profiles formed after the cessation of a horizontal infiltration is presented. A number of different initial soil water contents before the initiation of the horizontal infiltration and different infiltration depths were analyzed using the HYDRUS-1D software package considering the appropriate hysteretic wetting and drying curves. The effect of neglecting hysteresis was also investigated for the same conditions. The main wetting and drying boundary curves of the studied porous medium and the hydraulic conductivity at saturation were experimentally determined. The theoretical and numerical analysis indicated that the form of the redistributed soil water content profiles in the presence of hysteresis was similar to the original infiltration profile independently of whether the initial soil water content was taken on the boundary wetting or drying curve and independently of the porous medium type. Specifically, in a relatively short time after the initiation of the redistribution process, the magnitude of the soil matrix head gradient tended to zero due to hysteresis, and this resulted in an insignificant soil water movement, although the soil water content and the hydraulic conductivity values were still high. In addition, the redistribution proceeded at a faster rate than the smallest depth of infiltration water prior to the redistribution, and it was faster during the early stages of the redistribution. Accordingly, hysteresis is important for the simulation of horizontal soil water redistribution as it is, for example, in the case of localized irrigation systems’ design and management.

Use of the APSIM wheat model to predict yield, drainage, and NO3- leaching for a deep sand

1998 ◽  
Vol 49 (3) ◽  
pp. 363 ◽  
Author(s):  
S. Asseng ◽  
G. C. Anderson ◽  
F. X. Dunin ◽  
I. R. P. Fillery ◽  
P. J. Dolling ◽  
...  
Keyword(s):  
Grain Yield ◽  
Water Content ◽  
Soil Water ◽  
Soil Water Content ◽  
Western Australia ◽  
N Uptake ◽  
Inorganic N ◽  
Potential Yield ◽  
Soil Inorganic N ◽  
Initial Soil

High rates of drainage and leaching of nitrates in deep sands in Western Australia are contributing to groundwater recharge and soil acidification in this region. Strategies are being soughtto increase water and nitrogen (N) use in the legume-based cropping systems. Choice of appropriate management strategies is complicated by the diversity of soil types, the range of crops, and the inherent season to season variability. Simulation models provide the means to extrapolate beyond the bounds of experimental data if accurate predictions of key processes can be demonstrated. This paper evaluates the accuracy of predictions of soil water content, evapotranspiration, drainage, inorganic N content insoil, nitrate (NO-3) leaching, wheat growth, N uptake, and grain yields obtained from the Agricultural Production Systems Simulator (APSIM) model when this was initialised with appropriate information on soil properties and wheat varieties commonly grown on deep sands in the 500 mm rainfall zone west of Moora in Western Australia. The model was found to give good predictions of soil water content,evapotranspiration, deep drainage, and overall NO-3 leaching. Temporal changes in inorganic N insoil were simulated, although the small concentrations in soil inorganic N precluded close matching of paired observed and predicted values. Crop growth and N uptake were closely predicted up to anthesis, but a poor fit between observed and predicted crop growth and N uptake was noted postanthesis. Reasons for the discrepancies between modelled and observed values are outlined. The model was run with historical weather data (81 years) and different initial soil water and inorganic soil N profiles to assess the probability of drainage and NO-3 leaching, and the grain yield potentials for wheat grown on deep sands in the region west of Moora. Simulation showed that thesoil water and the soil inorganic N content at the beginning of each season had no effect on grain yield, implying that pre-seed soil NO-3 was largely lost from the soil by leaching. There was a 50% probability that 141 mm of winter rainfall could drain below 1·5 m and a 50% probability that 53 kgN/ha could be leached under wheat following a lupin crop, where initial soil water contents andsoil NO-3 contents used in the model were those measured in a deep sand after late March rainfall. Simulated application of N fertiliser at sowing increased both grain yield and NO-3 leaching. Splitting the N application between the time of sowing and 40 days after sowing decreased NO-3 leaching,increased N uptake by wheat, and increased grain yield, findings which are consistent with agronomic practice. The high drainage and leaching potential of these soils were identified as the main reasons why predicted yields did not approach the French and Schultz potential yield estimates based on 20 kg grain yield per mm of rainfall. When the available water was reduced by simulated drainage, simulated grain yields for the fertilised treatments approached the potential yield line.

Factors influencing salt and water movement near crystalline salts in relatively dry soil

Soil Research ◽  
1974 ◽  
Vol 12 (2) ◽  
pp. 77 ◽  
Author(s):  
DR Scotter
Keyword(s):  
Water Content ◽  
Soil Water ◽  
Soil Water Content ◽  
Soil Texture ◽  
Water Movement ◽  
Factors Influencing ◽  
Initial Soil ◽  
Crystalline Salt ◽  
Water Accumulation ◽  
Dry Soil

Crystalline salts were placed at one end of sealed tubes of initially uniformly wet soil. The effect of soil texture, the initial soil water content, temperature, and the particular salt used on the resulting water and salt distributions in the soil was studied. In all experiments using relatively dry soil a zone of water accumulation adjacent to the salt, and a zone of water depletion further away from the salt, developed. Dissolved salt moved into the wetter zone next to the salt. The rate at which salt dissolved and moved out into the soil was found to depend very strongly on the solubility and saturated solution vapour pressure of the salt used, and the initial soil water content. Soil temperature and texture were less important factors. In some experiments quite large amounts of water accumulated in the crystalline salt, apparently when adequate contact was not maintained between the salt and the soil as the salt dissolved.

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