New Zealand Journal of Agricultural Research abstracts
A statistical analysis of international test methods used for
analysing
spreader performance
H. G. Lawrence
I. J. Yule
New Zealand Centre for Precision Agriculture
Institute of Technology and Engineering
Massey University
Private Bag 11222
Palmerston North 4442, New Zealand
J. R. Jones
Institute of Technology and Engineering
Massey University
Abstract There are a number of tray testing
methods used
throughout the world to assess the distribution accuracy of fertiliser
spreaders, all of which calculate differences in distribution pattern.
The main objective of this work was to perform a statistical analysis
of the differences between methods. The effect of variations in
calculated bout width due to change in distribution pattern was
investigated. Six international test methods were compared
simultaneously using a matrix of 1400 trays, each 0.5 × 0.5 m.
Each test method was able to be extracted from the tray matrix. Urea
fertiliser (46% N) was used for all tests at three application rates,
80, 100, and 150 kg ha - 1. A simulation model created in
@RISK was used to predict certifiable bout widths from each test method
using overall spread pattern characteristics and statistics. Results
indicated that there were major variations in calculated certifiable
bout width using the different methods. Tray layout within ±5 m
of the spread line had the biggest effect on calculated bout width.
Method designs that incorporated trays in the longitudinal direction
were more accurate in predicting the average variation than when a
single transverse test was used. In conclusion, if comparison is
required between two or more spreaders, the same test method and tray
layout should be used. Having a sufficient concentration of trays
within ±5 m of the centre of the distribution pattern will
describe the behaviour of a spreader with greater accuracy.
Keywords centrifugal fertiliser spreading;
fertiliser
spreader testing; spread pattern statistics; precision agriculture
A06020; Online publication date 25 October 2006 Received 6 April
2006; accepted 20 September 2006
New Zealand Journal of Agricultural Research, 2006, Vol. 49:
451–463
0028–8233/06/4904–0451 © The Royal Society of New Zealand
2006
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