Positive 
  
U.S. trade balance (billion dollars) 
  
  
  
  
  
  
  
2 
2 
"I 
2 
2 
[] Non-agricuiture | a 
Agriculture | 
J Net difference 
  
  
1 L | | 1 1 | | 1 
50 60- 70 71 72 73 74 75 76 77 
52 62 
  
Years 
I 
  
  
| Source: Economic Research Service and Council 
on International Economic Policy 
| 
  
Figure 2.— U.S. trade balance for non- 
agriculture, agriculture, and the 
difference. 
The problem of extreme variation in 
crop production over time is not new; 
feast-and-famine cycles have played a 
primary role in the development of 
civilization through the ages. In the 
late 1950's and early 1960's, with the 
dawn of space age technology, a number 
of scientists and planners began to 
consider using Earth-orbiting satellites 
as an improved vantage point to monitor 
important agricultural crops. In the 
late 1950's, the Agricultural Board of 
the National Research Council began to 
study the problem of obtaining more 
accurate and timely agricultural infor- 
mation (1). At the Board's recommen- 
dation, the Committee on Remote Sensing 
for Agricultural Purposes was established 
in 1961. This multidisciplinary group 
concentrated on techniques having a 
potential for acquiring and analyzing 
relatively large quantities of data over 
large geographic areas within days or at 
most, weeks. The multispectral concept 
was developed and initial feasibility 
experiments conducted by scientists at 
the University of Michigan and Purdue 
University (2). In 1964, MacDonald 
     
recommended that a focal point for con- 
tinuing research be established in the 
scientific community and that NASA and 
USDA support this focused multidiscipli- 
nary consortium. 
In late 1965, the Laboratory for 
Agricultural Remote Sensing (LARS) was 
founded at Purdue University and a 
focused program initiated by scientists 
at the University of Michigan, the Uni- 
versity of California at Berkeley, and 
other institutions. The program imple- 
mented by this consortium resulted in a 
number of significant advances in the 
understanding of the multispectral 
radiation characteristics of natural 
materials and in the associated remote 
sensing technology. These included 
e An improved airborne multispectral 
sensor that recorded calibrated 
measurements at ultraviolet, visible, 
and infrared wavebands on machine 
processible magnetic tapes, thus in- 
creasing research and development 
capability (1965, 1966). 
e The development of digital data pro- 
cessing systems incorporating statis- 
tical decision algorithms to analyze 
multispectral measurements (1966). 
e The development of field spectro- 
meters to support research with control 
field plots to make on-site measurements 
of the radiation patterns of agricul- 
tural materials under different condi- 
tions (1966-1972). 
e The first demonstration of the capa- 
bility to identify wheat and other crops 
semiautomatically with the airborne 
scanner (1966). 
e The development of specifications for 
a spaceborne multispectral scanner to be 
flown on Earth Resources Technology 
Satellite A. 
e An "ERTS A" multispectral scanner 
simulation experiment (S0-65) flown on 
Apollo 9 (1969) (3). 
e The application of aircraft-mounted 
sensors to the detection and monitoring 
of a major crop disease (The Cornblight 
Watch) (1971) (4). 
   
    
  
  
  
   
   
  
  
  
  
  
  
   
    
  
  
  
  
  
  
  
  
  
   
   
  
  
   
   
  
  
   
  
  
  
  
  
  
  
   
  
   
  
  
   
  
   
  
  
  
  
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