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. <X> 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