Current could replace chemical herbicides in farming.
Pesticide use in agriculture is a key element in the Green Revolution that allowed the Earth’s population to increase dramatically post-WW2. Herbicides make up almost half of the total amount of agricultural chemicals used but increasing concerns about the health effects of residual chemicals in runoff and in the soil has led to legislation banning or reducing the use of many compounds. An Australian-German partnership has developed a unique system for killing agricultural weeds using electricity and a non-toxic conductive fluid that might allow truly organic farming with the high yields delivered by herbicides.
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Agricultural pesticides were one of the fundamental technologies behind the Green Revolution. Beginning in the 1950s and continuing through the 60s and beyond, the combination of high-yield crop varieties, chemical fertilizers, irrigation and pesticides saved millions from hunger and starvation.
Today, the world uses over two and a half million tons of pesticides, with herbicides making up the biggest portion, approximately 40 percent. U.S. use accounts for 22 percent of the world total, but on a per acre basis, China uses almost five times the amount as the United States, and Japan, even more.
Weeds are a serious problem in agriculture but increasing sensitivity to the environmental effects of agricultural chemicals, and tighter regulations on both chemical formulations and application, are driving research into alternative control techniques. On the demand side, the considerable market for organic produce, which generally commands higher prices, motivates farmers to find effective control strategies without chemicals.
NUCROP, a partnership between Victoria, Australia-based Nufarm and crop.zone from Aachen, Germany has developed a novel way to control agricultural weeds that the firm calls “Hybrid Electric Crop Protection.”
Unlike chemical herbicides, the system uses electrical current to shock plants, destroying their ability to take up water so that they desiccate and die. Equipment mounts to conventional agricultural tractors and consists of a front-mounted boom sprayer, and a rear PTO-mounted generator and applicator boom. The front sprayer deposits a nitrogen and phosphate-free mineral solution called Volt.fuel to enhance conductivity, while the rear boom trails surface contact applicator plates that expose the plants to a potential of between 2,000 to 5,000 volts. The volt fuel liquid bridges leaf hairs and irregularities on leaf surfaces and softens the plants surface wax layer to increase electrical conductivity and lower power consumption.
Initial tests on potato desiccation use a power take off mounted generator producing 112 kilowatts of electrical power, drawing 188 horsepower from the PTO shaft. The system operates with a boom 12 metres wide and can cover 15 acres per hour. Tractor operating speeds of six kilometres an hour, just under four miles an hour, have demonstrated good results and the company expects speeds of 8 to 9 kilometres an hour will be possible for potato desiccation.
Depending on the type of applicator, electric current may pass through the soil and kill roots, as well. Depth depends on the type of applicator, soil moisture content, plant species and amount of energy transferred, with Nucrop reporting the destruction of thistle tap roots to a depth of 15 centimetres so far.
The effect of electric current desiccation on soil life is still under study, and the company reports that testing so far has shown no effect on earthworms. Expansion to other crops will include wider boom widths and specific applicators for row crop operations. The company has an early adopter program operating in Germany, the Netherlands and France, and has begun testing in North America.
Could the secret to widespread, high-yield organic farming be electricity? We’ll know soon.
