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.