Geology Reference
In-Depth Information
8
Universal Soil Loss Equation
and Revised Universal Soil
Loss Equation
K.G. RENARD
1
, D.C. YODER
2
, D.T. LIGHTLE
3
AND S.M. DABNEY
4
1
USDA-ARS, Southwest Watershed Research Center, Tucson, AZ, USA
2
Biosystems Engineering and Soil Science, University of Tennessee, Knoxville, TN, USA
3
USDA-NRCS, National Soil Survey Center, Lincoln, NE, USA
4
USDA-ARS, National Sedimentation Laboratory, Oxford, MS, USA
8.1 Introduction
who was undoubtedly the most influential soil
conservationist in the US. His early efforts led to
his recognition as the 'father of soil conservation'.
Bennett's early preaching against the menace of
soil erosion led to Congressional action in 1929
establishing ten experimental stations, primarily
in the cultivated agricultural areas of the US
(Meyer & Moldenhauer, 1985; Renard, 1985).
Later expansion of the research programmes
included a large number of plots, crops, and man-
agement conditions that ultimately resulted in
over 10,000 plot-years of data, collected over
seven decades. Most of the plots involved the
familiar dimensions 6.0 ft (1.8 m) wide by 72.6 ft
(22.1 m) long, or a plot 35 ft (10.7 m) long used for
some rainfall simulator studies. These plots sim-
plified the computing of runoff and erosion on a
per unit area basis (0.01 acre for the 6 × 72.6 ft or
nominally 40 m
2
for the 1.8 × 22.1 m). Typical plot
configurations were described in Brakensiek
et al
.
(1979) and Laflen and Moldenhauer (2003).
In 1954, the National Runoff and Soil Loss
Data Center was established by the US Depart-
ment of Agriculture - Agricultural Research
Service (USDA-ARS) at Purdue University in
West Lafayette, Indiana. The Center was estab-
lished to provide a central location for compiling
and analysing soil erosion data collected from
studies throughout the US. The Center, under the
direction of W.H. Wischmeier, was responsible
8.1.1 History of the USLE
(Universal Soil Loss Equation)
Conservation of soil and water requires both
knowledge of the factors affecting these resources,
and methods for controlling those factors to pre-
serve those resources. Over the years, field, plot
and small watershed studies have provided much
valuable information regarding the complex factors
and interactions involved in the environmental
operations of land use and farming. These studies
are the basis of the Universal Soil Loss Equation
(USLE), which is a conservation planning tool that
has been demonstrated to do a reasonably good job
of estimating erosion for many disturbed-land uses.
Predicting soil loss associated with modern land
use is based on guidelines developed from research
information in combination with additional expe-
rience from many sources. Information from
empirical experiments and physically-based princi-
ples both assist in effective conservation planning.
The process of pulling together research results
and experiences from agricultural practices began
with Hugh Hammond Bennett (Helms, 2008),
