Agriculture Reference
In-Depth Information
Table 12.3 Errors of yield sensing systems for combine harvesters at different tilts in the
2000/2001 test bench studies
Sensing system (in bold), Meter
(in italics), Manufacturer (in brackets)
Relative calibration
error in % (average)
Standard deviation of
the relative error in %
Light-barrier, system 2,
CERES 2, (RDS)
−3.38
8.07
Light-barrier, system 2,
QUANTIMETER, (CLAAS)
−0.91
3.74
Light-barrier, system 2,
PRO SERIES 2000, (RDS)
−0.90
11.73
Radiation, system 3, FLOWCONTROL,
(MASSEY FERG.)
−1.11
2.17
Force, system 4, FIELDSTAR,
(DRONNINGB./AGCO)
−0.02
2.38
Force, system 5, YM 2000
(AGLEADER), LH 565 (LH AGRO)
−0.24
4.31
Force, system 6, GREENSTAR,
(JOHN DEERE)
−1.36
3.37
Constant throughput of 20 t h −1 ; lateral tilt of 5, 10 and 13° to the left and to the right or longitudinal
tilt forward and back as well as combinations thereof; 5 repetitions/variant; n = 60/m; reference
mass/variant = 1 t; winter wheat. For system numbers see Fig. 12.2 (Demmel 2001 )
systems on combine harvesters and simultaneously counter-weighed using a weigh
wagon or certifi ed scale. A mean calibration error of −1.1 % was detected with an
average error standard deviation of 3.6 %.
Each individual trial delivered between 4 and 39 control weights. The calibration
errors for these varied between +15.2 and −27.1 %. This shows that the precision of
calibration is a key issue, although most of the mean errors remained between
±10 %. At two locations the standard deviation of the error was above 10 %. The
results show an accuracy level comparable to the results reported by Demmel 2001
and emphasise the need of a repeated and accurate calibration.
To make the results of an evaluation of yield measurement systems for combines
comparable, ASABE Standard S578 ( 2007 ) provides the basic requirements for a
uniform procedure to measure and report yield monitor accuracy. It describes a
series of repeatable tests that may be used to evaluate and compare grain fl ow
sensors in laboratory testing. In addition ASABE Standard S579 (2012) defi nes a
“Yield Monitor Field Test Engineering Procedure” and provides the basic require-
ments for fi eld evaluating the accuracy of yield monitors (ASABE 2007 , 2012).
12.4
Yield Measurement for Forage Crops
Typical crop rotations in many regions of the world, especially in Western Europe,
do not only consist of combinable crops. To get information on the variability of
yields of different kind of crops, yield measurement systems for other harvesting
equipment than combine harvesters is necessary.
 
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