321
Symposium on Remote Sensing for Resources Development and Environmental Management / Enschede / August 1986
On the estimation of the condition of agricultural objects
from spectral signatures in the VIS, NIR, MIR and TIR wavebands
R.Sôllner, K.-H.Marek & H.Weichelt
Central Institute for Physics of the Earth, Academy of Sciences of the GDR, Potsdam
H.Barsch
Pedagocial University, Potsdam, GDR
ABSTRACT: During the Interkosmos-Experiment KURSK-85 the biometric indices of different
crops in the Kirov collective farm v/ere used as a measure for their productivity which
the interpretation of spectral signatures can refer to. A productivity criterion,
derived from the spectral signatures in the VIS, NIR, MIR and TIR wavebands was used for
the differentiation of the crops. The groups of vitality obtained in this way are in
good correspondence with the ground reference data.
1 SURVEY APPROACH
The information value of remote sensing
data of agricultural objects exceeds by
far the ascertainment of the size and the
spatial distribution of the sowing areas
and furthermore permits the recognition
of differentiation levels in the state of
crops, their spreading and their proportions
of the entire area. Partly this is already
possible with the interpretation of the
spectral signatures of the agricultural
targets in the red band of the visible
light (VIS) and in the near infrared
spectral band (NIR). In this connection
much more extensive and complex information
is derivable if additionally the spectral
signatures of the medium (MIR) and thermal
infrared (TIR) as well as the microwave
band (MW) are registered (cf. among
others BAR SC H, MAREK, S'ÜLLNER , WEICHELT
1984 ; BAUER, VANDERGILDT, ROBINSON 1980;
MIGUET, BARET, GUYOT 1983; VASILEV,
KACINSKI 1984). The interpretation of
these signatures demands an efficient
physical model for the diagnosis of the
connection between Geophysical plant
features and the spectral signatures. For
the deveploment and the qualification of
these model conceptions the terrestrial
measurements of these features have to be
related to the remote sensing data.
In the Interkosmos Programme experimental
surveys for the designation of the yield
formation of crops with remote sensing
data are therefore carried out on different
survey levels (VASILEV, VEDESIN 1933).
Accordingly the application of aerospace
as well as terrestrial sensors for spectral
signature measurements in VIS, NIR, MIR,
TIR and MW-band was coupled with pedological
and biometrical soil testing during the
Interkosmos Experiment KURSK-85. The
contribution of the GDR to that experiment
was concentrated on the participation in
terrestrial soil and biogeographical
surveys and in spectral signature
measurements in the lower survey levels,
especially trajectories.
2 METHODOLOGY AND RESULTS OF TERRESTRIAL
SURVEY
In the forest steppe, north and south of a
communication road, which 25 km south of
Kursk branches off the main motorway Moscow-
Kursk-Charkov in easterly direction and
crosses the loess-territory of the
collective farm Kirov, soil
(chernozem) and vegetation samples from
12 fields were taken at a length of about
5 km. This was done at altogether 27 test
spots because differences in the stock
density and the plant development within
the and plots had to be taken into
consideration. The designation of
components of the yield formation through
soil and vegetation features was partly
immediately carried out on the terrain
(soil colour, stock density, stock height,
phenology, drilling clearance, humid mass
of soil and plant), partly it was done in
the laboratory of the Kursk research
station of the Geographical Institute of
the USSR Academy of Science (dry residue
of soil and plant, crop.index spectro-
metrically after HOLM and LEFORT, leaf
area index - LAI) C
The results show fig. 1, 2.
The consideration or the spatial
differentiation of the soil features made
clear that the highest indices of the
soil humidity, the KUK and the content
of organic substances, the best humus
quality and the darkest colours of the
upper soil are to be found in the centre
of the loess plates. Sites at the margin
of the plates, marked here by the working
plots 56, 57 and 58 as well as (at the
roots of erosion hollows) the working
plots 36 and 42, show significant
degradation symptoms of the soil in the
loess black earth through lower indices.
But here, too, the pedological parameter
still show a high soil fertility. The
boundary conditions for the yield forma
tion here result from the climate, espe
cially from the shorter duration of the
vegetation period in comparison to Central
Europe (185 daily means above 5°C, 130
days above 10°C) and the high summer
evapot ranspiration.
