Smart Sprayer Selects Weeds for
Weeds in soybean fields are taking a beating from a smart sprayer that
combines computer chips, high-power light, and infrared emitters with sensitive
silicon photo detectors to determine the precise location of individual weeds.
A combination of sprayer heads applies herbicide in short bursts directly
onto foliage, without spraying the surrounding area.
The sprayer, originally developed for use in orchards and vineyards, has
shown promise for killing weeds between the rows in some crops while reducing
herbicide use, says ARS agricultural engineer James E. Hanks. He is in the
Application and Production Technology Research Unit at Stoneville. Mississippi.
Herbicides for weed control in soybeans and cotton represent a major
production cost for producers.
"The grower who applies herbicides with this type of controlled
precision is definitely going to save on production costs," he says.
"Herbicides won't be wasted on areas of bare soil."
Hanks isn't just making an educated guess. He adapted the smart sprayer for
use in controlling weeds in soybeans on a farm in Leland. Mississippi. He cut
holes in the tops of spray hoods so nozzle-equipped sensors could be added to
them. When the sensors detect green plant material under the hood, a spray
nozzle is activated, releasing herbicide onto weeds growing between crop rows.
ARS recently signed a cooperative research and development agreement with
Patchen California, Inc., of Los Gates, California, to develop a system to use
the smart sprayer for row crops.
On Dean Cumbaa's Leland-area soybean farm, Hanks used an in-row hooded spray
system. Half was equipped with sensor-controlled spray hoods and the other half
with conventional continuous spray hoods. In the half where he used the
intermittent sprayer to apply herbicides, weeds were killed with only one-half
herbicide used by the continuous sprayer. Weed control was the same for both
methods, reports Hanks.
Results of the study done in the spring of 1995 showed that applying
chemicals with intermittent sprayers reduced chemical use on soybeans by 50 to
"Even using much less herbicide, we achieved excellent weed
control," says Hanks.
That's because the sprayer heads put the herbicide down only where weeds are
detected. It has found weeds as small as three-fourths of an inch in diameter.
In 1996, Hanks will test the technology on cotton and re-evaluate its use in
soybeans. By Linda Cooke, ARS.
Hanks is in the USDA-ARS Application Production Technology Research Unit,
Stoneville, MS 38776; phone: (662) 686-5382.
"Smart Sprayer Selects Weeds for Elimination" was published
in the April
1996 issue of Agricultural Research magazine.