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3.MBASUREMENT OF SPECTRAL CHARACTERISTICS ON PADY FIELD
To monitor a fertilization management for a large paddy field
and to forecast the rice yield is one of the most desired application
of the remotesensing technique, as the rice is the main dish in
daily life in Japan. And the remote sensing can be easily applied
to a rice field as the rice field is located on a flat field and
each field is separated clearly from other fields.
It is the basic requirement to make clear the relation between
a growing process and a spectral characteristics of the rice.
So the following three terms were studied for a spectral radiance
measurement in the rice field,
(1). The analysis of the relation between the spectral characteristics
and the difference of the fertilizing status on the fields fertilized
with the different way.
(2). The effect of the viewing angle for the spectralradiance
characteristics of the rice field.
(3). The analysis of the relation between the spectral radiance
characteristics and the growing condition which is indicated with
the Leaf Area Index, the biomass, the horizontal projection area
and so on.
And then, the most suitable wave length and range of the remote
senser for the rice field were studied through the wave length range
dependency and the change of the season.
3-1. TEST FIELD
The test field is located at Inbagun in Chiba-pre., and is one
of the typical rice field in the rural area of Tokyo.
Three different fertilizing codrate which were 2 by 2m were
prepared for this study, and the test field is shown in Table-3-1.
The field spectral radiance measurement were done every week from
June 25 ( young rice ) to September 3 ( hearvest ) in 1977.
The growing status of rice were recorded with the height of
the rice stump, the number of the stems per the stump, the number
of the ears per the stump, and the pictures were taken from three
different directions for the horizontal projection area and for the
virtical leaf prjection area.
And the sample rice stump was taken from the test field to
measure the spectral radiance of each leaf and each ear in the
laboratory. The Leaf Area Index and the biomass were also measured
with the sampled stump.