K. Rajkai et al., ESTIMATION OF WATER-RETENTION CHARACTERISTICS FROM THE BULK-DENSITY AND PARTICLE-SIZE DISTRIBUTION OF SWEDISH SOILS, Soil science, 161(12), 1996, pp. 832-845
A Swedish soils database containing soil-water retention data, particl
e-size fractions, dry bulk. density, and organic matter content was an
alyzed in order to find a relatively simple predictor of the soil-wate
r retention curve (SWRC), As a SWRC model we chose a three-parameter f
unction selected hom nine van Genuchten-type retention models that wer
e fitted to the measured retention data by nonlinear parameter optimiz
ation. Cumulative particle-size (CP) data were described by a logistic
distribution model, Additionally, the mean and standard deviation of
the CP distribution were estimated directly from the measured particle
-size data, Regression equations were subsequently used to estimate th
e parameters in the selected SWRC model from available soil properties
, particle-size data, and CP distribution parameters, Four alternative
pedotransfer models were formulated to estimate the SWRC curve from t
he basic soil properties, These models predicted the SWRC curves from
either the original soil data or from the CP distribution parameters,
A mean estimation error of less than 2.5% was used to indicate a good
estimation, The highest ratio (67%) of good estimations and the lowest
ratio (12%) oh poor estimations were obtained when both the original
soil properties and the CP model parameters were used, Our study shows
that the resulting simple SWRC model gives a good description and a u
sable prediction of the retention properties of Swedish soils for a wi
de range of soil textures.