and as results of these efforts are evaluated, appropriate candidate
techniques will be tested in the environment described herein.
IV. Conclusion
Agrophysical units (APU's) offer a method for partitioning the agri-
cultural universe into different geographical areas having definable
agronomic and physical parameters. These units were derived from
interpreting and synthesizing Landsat imagery, soil maps, and meteor-
ological/climatic data.
Investigations were conducted in the Great Plains of the United States
to determine the usefulness of agrophysical units within the Large
Area Crop Inventory Experiment (LACIE). The conclusions from this
study are: 1) LACIE sample population was reduced by 23 percent;
2) wheat yields are significantly less variable within agrophysical
units than they are within crop reporting districts. This suggests
that yield models be run over agrophysical units rather than crop
reporting district. 3) Data analyses can be conducted with less
time and improved accuracy by employing information contained within
an agrophysical unit; 4) improved methods can be obtained for monitor-
ing adverse climatic conditions that affect plant growth.
An automated agriculture data base was built using APU as the master
data set. Linked to the master is "N" number of secondary data sets.
These secondary sets are country/region specific and contain generic
elements such as multispectral data, yield model forms, and com-
modity statistics. These secondary data sets can be activated and
combined with the master data set when needed for a specific type
of analysis. This type of system offers versatility and efficiency
in conducting analyses using remotely sensed data.
This data base and its associated hardware system provide an efficient
storage, retrieval, and manipulation environment for massive data
sets and also the capability to rapidly respond to the user's chang-
ing information needs.
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