Open Journal of Soil Science, 2012, 2, 203-212
http://dx.doi.org/10.4236/ojss.2012.23025
Published Online September 2012 (http://www.SciRP.org/journal/ojss)
203
Test of the Rosetta Pedotransfer Function for Saturated
Hydraulic Conductivity
Carlos Alvarez-Acosta
1
, Robert J. Lascano
1
, Leo Stroosnijder
2
1
USDA-ARS
*
Cropping System Research Laboratory, Wind Erosion and Water Conservation Research Unit, Lubbock, USA;
2
Land
Degradation and Development Group, Soil Science Centre, Wageningen University, Wageningen, Netherlands.
Email: carlosalvarez83@gmail.com, Robert.Lascano@ars.usda.gov, Leo.Stroosnijder@wur.nl
Received April 28
th
, 2012; revised May 30
th
, 2012; accepted June 10
th
, 2012
ABSTRACT
Simulation models are tools that can be used to explore, for example, effects of cultural practices on soil erosion and
irrigation on crop yield. However, often these models require many soil related input data of which the saturated hy-
draulic conductivity (K
s
) is one of the most important ones. These data are usually not available and experimental de-
termination is both expensive and time consuming. Therefore, pedotransfer functions are often used, which make use of
simple and often readily available soil information to calculate required input values for models, such as soil hydraulic
values. Our objective was to test the Rosetta pedotransfer function to calculate K
s
. Research was conducted in a 64-ha
field near Lamesa, Texas, USA. Field measurements of soil texture and bulk density, and laboratory measurements of
soil water retention at field capacity (–33 kPa) and permanent wilting point (–1500 kPa), were taken to implement
Rosetta. Calculated values of K
s
were then compared to measured K
s
on undisturbed soil samples. Results showed that
Rosetta could be used to obtain values of K
s
for a field with different textures. The Root Mean Square Difference
(RMSD) of K
s
at 0.15 m soil depth was 7.81 10
–7
m·s
–1
. Further, for a given soil texture the variability, from 2.30
10
–7
to 2.66 10
–6
m·s
−1
, of measured K
s
was larger than the corresponding RMSD. We conclude that Rosetta is a tool
that can be used to calculate K
s
in the absence of measured values, for this particular soil. Level H5 of Rosetta yielded
the best results when using the measured input data and thus calculated values of K
s
can be used as input in simulation
models.
Keywords: Rosetta; Saturated Hydraulic Conductivity; K
s
; Pedotransfer Function
1. Introduction
In order to model soil physical processes related to soil-
water content, it is important to know the hydraulic
properties of the soil [1]. Vigiak et al. [2] also remarked
the importance of characterizing soil hydraulic parame-
ters in order to understand the occurrence and movement
of overland flow at field, hill-slope, and catchment scale.
These soil hydraulic properties include the saturated (K
s
)
and unsaturated hydraulic conductivity, and the water
retention curve. Furthermore, in any modeling study on
water flow and solute transport in soils, the water reten-
tion and hydraulic conductivity functions for soil hori-
zons in the profile are crucial input parameters [3]. Ex-
amples of two simulation models that require soil hy-
draulic properties as inputs are the Energy Water Balance
Model [4,5] and HYDRUS [6,7]. In addition, soil hy-
draulic properties are a required input in models used to
calculate water runoff and soil erosion, e.g. Precision
Agricultural Landscape Modeling System [8-10] and ex-
amples of other models are given by Aksoy and Kavvas
[11].
Although the soil hydraulic properties can be measured
directly, this practice is both costly and time-consuming,
and sometimes results obtained are unreliable because of
the associated soil heterogeneity and experimental errors
[12,13]. When large areas of land are under study, it is
virtually impossible to perform enough measurements to
be meaningful, indicating the need for an inexpensive
and rapid way to determine soil hydraulic properties [14].
For example, some research results indicated that in a
10-ha field, 1300 measurements would have to be made
in order to accurately measure saturated hydraulic con-
ductivity to within 10% of the mean value [13]. Further-
more, Stroosnijder [15] indicated that measurements
*
The US Department of Agriculture (USDA) prohibits discrimination in
all its programs and activities on the basis of race, color, national origin,
age, disability, and where applicable, sex, marital status, familial status,
arental status, religion, sexual orientation, genetic information, poli
i-
cal beliefs, reprisal, or because all or part of an individual’s income is
derived from any public assistance program.
alo
ne would provide data difficult to extrapolate in time
and space, meaning that erosion in large fields would not
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