Relationship between particle size summation curves and the moisture characteristic curve for soilless substrates

2021 ◽  
pp. 209-218
Author(s):  
M. Zazirska ◽  
J.S. Owen ◽  
J.E. Altland ◽  
J.S. Fields
Keyword(s):  
Particle Size ◽  
Characteristic Curve ◽  
Moisture Characteristic

scholarly journals A scaling approach, predicting the continuous form of soil moisture characteristics curve, from soil particle size distribution and bulk density data

2013 ◽  
Vol 10 (11) ◽  
pp. 14305-14329 ◽  
Author(s):  
F. Meskini-Vishkaee ◽  
M. H. Mohammadi ◽  
M. Vanclooster
Keyword(s):  
Particle Size ◽  
Soil Moisture ◽  
Particle Size Distribution ◽  
Size Distribution ◽  
Characteristic Curve ◽  
Soil Samples ◽  
Continuous Form ◽  
Packing Parameter ◽  
Physically Based ◽  
Moisture Characteristic

Abstract. A substantial number of models, predicting the Soil Moisture Characteristic Curve (SMC) from Particle Size Distribution (PSD) data, underestimate the dry range of the SMC especially in soils with high clay and organic matter contents. In this study, we applied a continuous form of the PSD model to predict the SMC and subsequently, we developed a physically based scaling approach to reduce the model's bias at the dry range of the SMC. The soil particles packing parameter, obtained from the porosity was considered as a characteristic length. The model was tested by using eighty-two soil samples, selected from the UNSODA database. The result showed that the scaling approach properly estimate the SMC for all soil samples. In comparison to the formerly used physically based SMC model, the proposed approach improved the model estimations by an average of 30% for all soil samples. However, the advantage of this new approach was larger for the fine and medium textured soils than that for the coarse textured soil. In view that in this approach there is no further need for empirical parameters, we conclude that this approach could become applicable for estimating SMC at the larger field scale.

COMPARISON OF METHODS FOR DETERMINING SATURATED HYDRAULIC CONDUCTIVITY AND DRAINABLE POROSITY OF TWO SOUTHERN ALBERTA SOILS

1986 ◽  
Vol 66 (2) ◽  
pp. 249-259 ◽  
Author(s):  
G. D. BUCKLAND ◽  
D. B. HARKER ◽  
T. G. SOMMERFELDT
Keyword(s):  
Soil Moisture ◽  
Hydraulic Conductivity ◽  
Characteristic Curve ◽  
Subsurface Drainage ◽  
Saturated Hydraulic Conductivity ◽  
Drainage Design ◽  
Moisture Characteristic ◽  
Constant Head ◽  
Subsurface Drains ◽  
Drainable Porosity

Saturated hydraulic conductivity (Ks) and drainable porosity (f) determined by different methods and for different depths were compared with those determined from the performance of drainage systems installed at two locations. These comparisons were made to determine which methods are suitable for use in subsurface drainage design. Auger hole and constant-head well permeameter Ks were 140 and 110%, respectively, of Ks determined from subsurface drains. Agreement of horizontal or vertical Ks, from in situ falling-head permeameters; to other methods was satisfactory providing sample numbers were large. Ks by Tempe cells was only 3–10% of drain Ks and in one instance was significantly lower than Ks determined by all other methods. At one site a profile-averaged value of f determined from the soil moisture characteristic curve (0–5 kPa) of semidisturbed cores agreed with that determined from drainage trials. At the other site, a satisfactory value of f was found only when the zone in which the water table fluctuated was considered. Results indicate that Ks determined by the auger hole and constant-head well permeameter methods, and f determined from the soil moisture characteristic curve of semidisturbed cores, are sufficiently reliable and practical for subsurface drainage design. Key words: Subsurface drainage, hydraulic conductivity, drainable porosity

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