Physical and Cultural Weed Control Working Group of - European ...

9 th EWRS Workshop on Physical and Cultural Weed Control 87
Samsun, Turkey, 28 – 30 March 2011
Maintenance of railway embankments - how to use the Yara N-sensor
for prognosis of weed control measures
Fredrik Fogelberg 1 and Anders Larsolle 2
1) JTI - Institute of Agricultural and Environmental Engineering, POB 7033, SE-750 07 Uppsala,
Sweden
2) Swedish University of Agricultural Sciences, POB 7033, SE-750 07 Uppsala, Sweden.
Introduction
Railway embankments in Sweden need to be weeded regularly in order to keep the track in
good technical condition. Today, this weeding is carried out mainly by herbicides and is based on
local contractors’ possibility to find suitable time for this kind of work. There are no general
recommendations of acceptable level of weed infestation.
The Swedish Railway Maintenance Authority (SRMA) has experienced difficulties in making
prognosis for when and where the weed control should take place in order to optimise staff,
machines and suitable measures for the weeding operation.
One major problem is the time consumption to identify a need for weeding, i e. are there too
much weeds on the tracks which may impair train performance or is the level of weeds too small to
motivate herbicide use.
Material and methods
In the pilot project we have used the Yara N-sensor as a tool for weed infestation assessment. A
test rig was constructed for use on railway tracks (fig 1). This rig was equipped with the N-sensor
including software and a GPS. By moving the test rig on a railway line in central Sweden, we
obtained data on biomass, expressed as S/N-value, which could be connected to a visual assessment
of the weed coverage on the track.
We did not measure weed density expressed as weight or percent coverage, only as a visual
estimation of the amount of vegetation on the tracks being ‘non-existent’ (fig 2), ‘acceptable’,
‘increasing’ (fig 3) and ‘non-acceptable’ (fig 4).
Based on the measurements of the N-sensor a “weed map” of the railway line could be
constructed (fig 5).
Results and discussion
The N-sensor identifies presence of vegetation which in turn can be connected with a herbicide
treatment. However, although all vegetation on railway tracks should be removed, economical
restrictions, lack of equipment and unsuitable weather conditions prevents herbicide use or other
weed control measures.
By using the N-sensor as a tool to detect unwanted vegetation on tracks in combination with a
system for classifying weed coverage, an action plan for maintenance of the railway tracks on a
national level can be created.
A first step to introduce this system, is to identify levels of acceptable and non-acceptable
weeds (species) and/or weed coverage. These levels will be connecting presence of weeds with the
function of the railway, i.e. standard of the track in terms of e g maximum load of wagons and