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AN AGRICULTURAL DATA BASE TO
SUPPORT DIVERSE REMOTE SENSING APPLICATIONS
By J. D. Murphy, G. A. May, and J. M. Downs
USDA LACIE Project, Houston, Texas
I. Introduction
The Large Area Crop Inventory Experiment (LACIE) is a cooperative
effort by the United States Department of Agriculture (USDA), the
National Aeronautics and Space Administration (NASA), and the
National Oceanic and Atmospheric Administration (NOAA). It is an
experiment designed to demonstrate the applicability of remote
sensing technology for globally monitoring wheat, an important
world food crop.
Experience obtained in 1975 and 1976 indicated a need to develop a
method for reducing various variabilities within the experiment.
Throughout the agricultural universe there are significant differences
in land use, cultural practices, soils, and climate. These factors
play an important role in agricultural production. A method needed
to be developed that could capture and define the variability caused
by these factors.
Several approaches were considered for identifying and isolating some
of the LACIE variability. One approach was to work at a small polit-
ical division such as the county level, using county statistics and
soil reports to define the variability in wheat production factors.
This method would require detailed statistics not available for
application in most areas outside of the United States. This amount
of data would also create a data handling problem. Another approach
could be to define variability at a larger division, such as a state
or oblast, but factors affecting wheat production are geographically
oriented and generally are independent of political and/or administra-
tive boundaries.
The selected approach to decreasing variability in large area estima-
tion of agricultural crops is to treat an agricultural area as a single
unit and divide it into subunits that 1) capture definable agronomic
and physical parameters and associated variability that affect crop
production, and 2) are easily manageable within the LACIE operation.
Thus, the rationale for an agrophysical unit (APU). An APU is a
geographical area having definable/comparable agronomic and physical
parameters which reflect a range in agricultural use and management.
After gaining experience with APU's, it became apparent that they
were universally applicable as a baseline for varied analyses using
remotely sensed data. The physical structure of these units would
give versatility to a data base system. Thus evolved the concept
of an automated agricultural data base using APU's. The USDA Early
Warning and Crop Assessment Application Test unit is currently de-
veloping such a system.