Geology Reference
In-Depth Information
task of expanding the initial minimal core vegeta-
tion and operation descriptions for NRCS use on
cropland and pastureland, as well as assisting
with the development of detailed climate descrip-
tions, and directing and managing the importing
of soils data for all available soil surveys. Working
with many colleagues, the database czar popu-
lated a single nationally-coordinated database of
climate, soils, operations, vegetations, residue
and support practice descriptions. For consist-
ency, field office users were 'locked out' of edit-
ing the data in these parts of the database.
Because the national database was vast, it was
organized into sections that could be downloaded
from the NRCS website for use in local conserva-
tion planning. Soils data were organized by state
and county or soil survey area. Thus, only the
soils data that a particular field office or user
needed would be contained in the local database,
although another soils description could be
imported as needed. Climate data were organized
by state for use in the same way. Management
records were organized by Crop Management
Zones (CMZs), 75 regions of the country with
similar crops and tillage systems.
Climate records . Climate data were populated
for the entire US, including Alaska, Hawaii and
the Pacific islands, Puerto Rico and the Virgin
Islands. The effort included extraction of the
monthly parameters from the national 1960-1989
dataset (1960-1999 in some cases), with calcula-
tion of monthly EI values for stations with record-
ing intervals of 15 min or shorter. These data were
smoothed using several routines and visual
inspection to provide a relatively smooth erosiv-
ity density 'surface', which was then used to pro-
vide point values or, more commonly, an average
value over a county.
Soil records . Creation of soil descriptions in
RUSLE2 was eased by making direct use of the
NRCS NASIS/SURGO soil database and tools,
available online at http://soils.usda.gov/technical/
nasis/. This is based on an NRCS soils expert (usu-
ally the State Agronomist) downloading from
NASIS all of the necessary soil descriptions, then
running those through a RUSLE2 utility that
extracts the necessary information, tests it for con-
sistency, and puts it into the required RUSLE2 for-
mat. Most RUSLE2 soils databases include some
generic soil descriptions based on soil texture, and
these are often more appropriate for use with
highly disturbed and mixed soils like those on con-
struction sites and mine reclamation projects.
Management records . The RUSLE1 experience
used the approach of organizing the US by C fac-
tor or EI distribution zones in order to develop
and coordinate the issuance of C -factor sets for
common single crop and crop rotation scenarios.
With RUSLE2 implementation, this cropping
region concept was built upon with the creation
of 75 Crop Management Zones (CMZs), in which
common crops and tillage systems were described
in detail and saved as 'locked' RUSLE2 manage-
ment templates. CMZs are zones in which the
climate and other factors thought to control man-
agement are assumed to be constant and unaf-
fected by political boundaries. In other words,
within a CMZ the crops are likely to be grown
with very similar planting and harvest dates, as
well as similar tillage systems, and so on. For
example, one CMZ representing the central Corn
Belt stretches east from the southeastern corner
of Nebraska and northwestern corner of Kansas
through northern Missouri, and across central
Illinois, Indiana and Ohio. Another CMZ stretches
south along the eastern side of the Appalachian
range from Maryland into Alabama.
With national coordination, this effort involved
significant coordination among NRCS state agron-
omists in setting typical dates of operations and
creating these management templates to represent
the typical tillage systems used in growing the
important crops in each CMZ. Once a set of crop
management template descriptions was created by
a CMZ coordinator, it was submitted to the data-
base manager for inclusion in the national NRCS
RUSLE2 database. Each CMZ set was contained in
a separate RUSLE2 export file so it could be
imported into the local RUSLE2 database in each
field office located within the boundaries of that
CMZ. This provided a starting point for field offices
as they implemented RUSLE2, and also provided
consistency in the use of RUSLE2 since the locked
management templates were based on typical
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