Agriculture Reference
In-Depth Information
in vegetative growth of wheat plants, because of late nitrogen application in the
growth stage flower. This conclusion was obtained using the results of scanning with
pendulum-meters at two different times. In field C, nearly the same mean pendulum
angles for each sensing date were generated by the strips. The plant mass relations
were reflected by the measurements in the strips with a high level of correspondence
for the two fields. The reason why the measured pendulum angles did not reflect the
growth progress directly is because there are different pendulum parameters for each
sensing date.
The mean fertilizer rate for field A within the uniform strips was 53 (197) kg ha
-1
,
whereas within the four site-specific fertilized strips it was 48 (178) kg ha
-1
. The first
value of fertilizer rate is the amount of nitrogen and the value in brackets is CAN,
which had 27% nitrogen. The site specifically fertilized strips saved a total of 5 (19)
kg ha
-1
fertilizer—in other words, about 10% fertilizer reduction was achieved by
using the distribution of fertilizer rate. The mean fertilizer rates within the site spe-
cific fertilized strips were 60 (221) kg ha
-1
and 57 (212) kg ha
-1
for field B and field
C, respectively. The site specifically fertilized stripes saved a total of about 8 kg ha
-1
(about 12%) nitrogen fertilizer in both fields.
The results of yield measurements by both methods (weigh-bridge and yield
monitor) show that more grain was harvested at the center of the site-specifically
fertilized stripes (4.2/4.4% in field A). Both the weigh-bridge and the yield monitor
in the combine harvester measured yield difference. However, this did not mean that
this difference was the result of variable rate application, because numerous factors
influence the yield. The yield advantage for variable rate fertilization was 1.9/2.6%
in field C. However, a poor sensor calibration of the combine harvester in field C
caused a difference in the absolute yields measured by the two methods. In contrast
to fields A and C, the site-specifically fertilized strips yielded 0.5/2.2% less grain in
field B. This is because the uniform fertilized wheat strips obtained a better plant
growth indicated by the higher mean pendulum angle of 1.6. Because the objective
was to reduce fertilizing rate, site-specific nitrogen fertilization may cause lower
grain quality, which would be a serious problem in agricultural production. In this
study, there was no clear tendency of crude protein, protein quality, and falling num-
ber depending on the different fertilizing rates from 7 to 68 kg N ha
-1
in the three
fields, whereas the thousand kernel mass was obviously reduced in the parts of the
field with sparse vegetation.
9.4.3 A
PPLICATION
OF
U
NMANNED
H
ELICOPTER
FOR
R
EMOTE
S
ENSING
OF
M
AIZE
P
RODUCTION
Maize as a feed crop has high nutritive value and land productivity. Recently agri-
cultural machines have been widely applied to reduce the labor during the process
of cultivation and harvesting. The information about the quality and yield of maize
is very important over a very wide area in a production site for silage production
and quality control, the determination of the fertilizer level, optimization of harvest
time, avoidance of quality problems, and improvement of agricultural productivity.
Remote sensing systems equipped with hyperspectral imaging sensors have shown
their potential to acquire detailed information about the spatial variability in crop
