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

229
FIELD TRIAL 116 in 1983
it-plot de-
pf"). Whole-
March (Zl)
were 6 ran-
00 kg N per
it-plot de-
f"). Whole-
March (Zl)
were 5 ran-
Lt dressing
Total
0
20
40
60
80
a split-plot
stion", so-
treatments
des at all
kes stage
: stage 10.4
ig densities
itely random-
1 densities
;ds per m 2
'el will be
j combined
a split-plot
-minda", so-
treatments
ides at all
imbined with
Split-plot
4 nitrogen
3 within the
; 150 seeds
600 seeds
ogen level
*).
similar to
winter wheat
re: 100 seeds
100 seeds per
Level will be
g combined
GREEN REFL. (X)
FIELD TRIAL 116 in 1982
RED REFL. (X)
FIELD TRIAL 116 in 1982
INFRARED REFL. (X)
FIELD TRIAL 116 in 1982
DAYS AFTER SOWING
Figure 2: Seasonal change in (a) green, (b) red and
(c) infrared reflectance for two sowing dates (Zl
and Z2) and for two nitrogen levels (N1 and N4).
Field trial 116 in 1982.
a
GREEN REFL. (X)
FIELD TRIAL 116 in 1983
C INFRARED REFL. FIELD TRIAL 116 in 1983
DAYS AFTER SOWING
Figure 3: Seasonal change in (a) green, (b) red and
(c) infrared reflectance. Field trial 116 in 1983.
factors were
erial photo-
tral bands.
• two sowing
all three
is plotted
le patterns
lar. The re
ed with in-
the growing
April) only
ilar reflec-
sidered. At
the visible
end of the
,sed due to
; effect was
ister develop-
germination
i crop, re-
;hift in re-
.ve) nitrogen
: bands, but
:rared reflec
tance the shift in response due to sowing date also
was evident. In general, the effects in the infra
red spectral band were opposite to those in the
visible bands. There was a positive effect of ni
trogen on infrared reflectance in both crops
throughout the season.
In field trial 116 in 1983 treatment effects of
two nitrogen levels for two sowing dates are illus
trated in figure 3. The shift in response due to
sowing date again was evident. On most dates there
was a negative nitrogen effect in the visible bands
(mostly small in absolute value). Throughout the
season there was a positive nitrogen effect on in
frared reflectance in crops belonging to both sowing
dates. In the late-sown crop the nitrogen effect was
less pronounced than in the early-sown crop.
In addition to these effects, the influence of
soil moisture content at the beginning of the sea
son in 1983 is important. The influence of soil
moisture content on reflectance was the same for
all three spectral bands. Reflectances were rela
tively small at high soil moisture content of the
top soil (30 April: 54 and 9 days after sowing for
the early (Zl) and late (Z2) sown crop, respectively
(for the green reflectance no measurements were ob
tained on this date); and 30 May: 84 and 39 days
after sowing for the early and late sown crop, re
spectively) and large at low soil moisture content
DAILY PRECIPITATION DAILY PRECIPITATION 1983
Figure 4: Daily precipitation for the 1983 growing
season. 11-31 July: no rainfall data, because of
computer failure. Days of missions are indicated
by arrows.
(16 April and 6 May) (see figure 3 in relation to
figure 4).
Finally, the decrease in reflectance towards the
end of the growing season for the green and red
spectral bands in the early-sown crop should be men
tioned. This occurred for both the green and red re
flectances with the same treatments, which almost
rules out inaccuracies in measurement as the sole