The
purpose of this study is to examine if thermal (flame or steam) treatments
of crops and field borders in the spring, summer and fall can reduce
annual, biennial and perennial weeds common along the Colorado Front
Range. A flame treatment will be compared to a steam treatment efficacy
for the control of weeds and insects in alfalfa. Also, steam treatment
weed control will be investigated for use in non-cropland applications
such as irrigation ditch banks, irrigation pipes, and walkways between
beds, edges of the beds, and roadsides. The main focus of this study
is to research the effectiveness and economics of using thermal weed
control methods in crop and non-cropland. This project will also include
producing educational materials and hosting a field demonstration.
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| "Atarus Stinger" steam weeder. |
Thermal
weed control techniques (flaming and steam) typically apply heat directly
to the weed, quickly raising the temperature of the moisture in the
plant’s cambium cells. The rapid expansion of this moisture causes
the cell structure to rupture, preventing nutrients and water from
entering the stalk and leaves, with dieback resulting in most plant
species.
In
1999 A. Bertram investigated heat transfer rates of steam/air mixtures
for thermal weed control. He found that a thermal generator would
have to reach at least 60 degrees C in order to kill plant species
he tested in the laboratory.
The
thermal weeder called "Atarus Stinger" was developed in
1998 by Origin Energy of Australia. Its primary use was to eliminate
weeds in vineyards. Their thermal weed control system incorporates
a patented Water Quenched Combustion technology using special burners
to generate steam. This technology combines the steam with the hot
gases and air to give the best possible medium for speed of application
and lowest fire potential. According to research from Australia, all
annual weeds can be controlled as effectively as using the herbicide
Roundup (glyphosate) when thermal weed control is properly timed.
These results were from research conducted on grapes, potatoes and
turf.
At
this time little research has been done on this type of steam thermal
weeder in the United States. No research of this type has ever been
performed here in Colorado. Organic growers in Colorado and throughout
the United States have a need for independent, unbiased research to
determine the efficacy of such a device.
Because
of the variety of crops and non-crop sites used for this project,
we will need to adapt the steam thermal unit to suit our needs. This
will include the development of a trailer to carry the unit and special
attachments on the nozzle ends to direct and contain the heat and
steam. These special attachments will be necessary on the nozzle ends
for the various applications, i.e., weed control of a fence line would
require a different configuration from weed control along the edges
of plastic mulch. The estimated cost for machinery like this can run
in excess of $15,000, therefore we depend on donations and grants
to defray the costs of this device.