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Remote sensing for resources development and environmental management
Damen, M. C. J.

two different
The first one,
99 m
plant species
" which alrea-
be attained
, sugar beets,
touchstone for
at field with
have one of
r wheat, bar-
the rotation
2 S 2
2 F 2
1 N 2
11 m
nter wheat
e three inde
parameters are
) and nitrogen
and fungizid
) and nitrogen
These parame-
ifferences in
on in order to
al changes in
her so that we
tivation (cf.
r the collec-
It is divided
into 7 small pieces (cf. fig.3). The pieces at both
sides are reserved for reflection measurements (R),
the adjacent ones serve for taking out plants for the
laboratory analysis (TP) and the central piece will
be harvested at the end of the growing season to
determine the produced yield (H).
21 m *•
Figure 3 : Functional structure of a plot
3.2 Organizational concept
All measurements will be accomplished as simultaneous
as possible. During the reflection measurements some
plants will be taken out and transported to the
laboratory for analysis of the agronomic parameters.
The meteorologic data will be taken in parallel with
spectral information, while the geometric shape of
the plant targets is fixed by means of stereo pic
tures just before the measurement cycle starts. The
situation in the atmosphere is completely recorded on
videotape by means of a CCD video camera for each
cycle too.
In each plot spectral data will be collected for
three different targets with dimensions of 2.8*0.5 m^
approximately. With help of some positioning aides
for the radiometer it is tried to reproduce the
position of the targets for all measurements during
the growing season. This concept assures comparable
reflection data for each campaign, as the changes for
one target during the growing season may give an idea
about the development of selected plants.
3.3 Measuring program
The collected data may be divided into four classes :
- 1. Agronomic parameters
These parameters are necessary to describe the
development stage of plants, their health and bio
logic situation
- 2. Structure parameters
This means especially the geometric structure of
the measured targets including the surface topo
graphy of the whole target and the geometric shape
of single plants
- 3. Meteorologic data
The meteorologic data describes the microclimatic
situation in the cultivated fields and their envi
ronment. This gives an impression in which amount
energy like radiation, humidity or temperature is
available for the plants. Additionally, it is im
portant to know something about influences like
wind, which may affect the reflection measurement.
- 4. Radiometric data
The field measurement of the radiation reflected
from plant targets provides the most important
information for the remote sensing application and,
after correction of the raw data, should correlate
with the produced yield.
It is envisaged to adapt the measuring campaign to
the course of the plant growth. In general the mea
surements should be taken once in two weeks, while
for times with rapid changes in the plants the fre
quence will be higher. For the whole growing season
at least 10 cycles should be collected, assuming that
enough days with dry weather conditions are availab
3.4 Measuring technique
According to the above grouping, the measurements
will be taken as follows :
- 1. Agronomic data
All collected agronomic information is listed in
table 1. We have to distinguish between simple evalu
ated data like weights, length values or numbers,
subjective intrinsic values like stage of growth or
influence of disease, and data which needs special
equipment, as for some physiologic and morphologic
The pigment content, for example is determined with
help of spectroscopy, the internal structure of
leaves will be derived from small thin slices of cell
material, while potassium, sodium, nitrogen, and
sugar content are measured chemically.
All these values will be evaluated for different
parts of the plants. Wheat plants, for example, are
divided into six different fractions. Each fraction
contains a leaf and a part of the stem, whereas the
first fraction contains the ear. The division is
1. Physiology
- dry matter
- pigment content
- cell-wall constituents
- crude protein content
2. Morphology
- stage of growth
- stand height
- plant geometry
- number of leaves
- leaf area index
- leaf area density
- ground cover
- weight of beet leaves
- internal structure of leaves
- plant diseases
3. Beet body
- weight
- dry matter
- potassium, sodium, nitrogen,sugar content
Table 1 : Agronomic parameters