Article
Development of a Stereovision-Based Technique to
Measure the Spread Patterns of Granular
Fertilizer Spreaders
Simon R. Cool
1,2,
*, Jan G. Pieters
1
, Dejan Seatovic
3
, Koen C. Mertens
2
, David Nuyttens
2
,
Tim C. Van De Gucht
2
and Jürgen Vangeyte
2
1
Department of Biosystems Engineering, Ghent University, Coupure Links 653, 9000 Gent, Belgium;
Jan.Pieters@ugent.be
2
Fisheries and Food Research, Institute of Agricultural, Burg. Van Gansberghelaan 115, 9820 Merelbeke,
Belgium; Koen.Mertens@ilvo.vlaanderen.be (K.C.M.); David.Nuyttens@ilvo.vlaanderen.be (D.N.);
Tim.Vandegucht@ilvo.vlaanderen.be (T.C.V.D.G.); Jurgen.Vangeyte@ilvo.vlaanderen.be (J.V.)
3
Faculty of Information Management & Media, University of Applied Sciences, Moltkestrasse 30,
76133 Karlsruhe, Germany; Dejan.Seatovic@hs-karlsruhe.de
* Correspondence: simon.cool@ilvo.vlaanderen.be Tel.: +32-9-272-2821
Received: 10 May 2017; Accepted: 13 June 2017; Published: 15 June 2017
Abstract:
Centrifugal fertilizer spreaders are by far the most commonly used granular fertilizer
spreader type in Europe. Their spread pattern however is error-prone, potentially leading to an
undesired distribution of particles in the field and losses out of the field, which is often caused by
poor calibration of the spreader for the specific fertilizer used. Due to the large environmental impact
of fertilizer use, it is important to optimize the spreading process and minimize these errors. Spreader
calibrations can be performed by using collection trays to determine the (field) spread pattern, but
this is very time-consuming and expensive for the farmer and hence not common practice. Therefore,
we developed an innovative multi-camera system to predict the spread pattern in a fast and accurate
way, independent of the spreader configuration. Using high-speed stereovision, ejection parameters
of particles leaving the spreader vanes were determined relative to a coordinate system associated
with the spreader. The landing positions and subsequent spread patterns were determined using a
ballistic model incorporating the effect of tractor motion and wind. Experiments were conducted
with a commercial spreader and showed a high repeatability. The results were transformed to one
spatial dimension to enable comparison with transverse spread patterns determined in the field and
showed similar results.
Keywords: fertilizer; spread pattern; stereovision
1. Introduction
The applied quantity of N-fertilizer has a direct effect on agricultural productivity, environmental
pollution, food security, ecosystem health, human health and economic prosperity [
1
]. A recent
study [
2
] illustrates the large environmental impact of fertilizer in a wheat-to-bread supply chain.
The use of ammonium nitrate fertilizer alone accounted for 43.4% of the overall Global Warming
Potential (GWP) and 34.1% of the Eutrophication Potential (EP) in the production of a loaf of bread.
According to [
1
] the most immediate solutions to this fertilizer problem reside in increasing Nitrogen
Use Efficiency (NUE) while maintaining high yield, through improved crop plant physiology but
also through improved agronomic practices such as precision agriculture. Granular fertilizer is
mostly spread by centrifugal fertilizer spreaders [
3
,
4
] due to their robustness, simplicity, low cost
and large working widths [
5
,
6
]. The spreading process however is very sensitive to errors [
7
,
8
]. Poor
Sensors 2017, 17, 1396; doi:10.3390/s17061396 www.mdpi.com/journal/sensors
