Do atrazine and its triazine cousins have any value to Cornbelt farmers? After all, the EPA is continually in a process of re-registering its use, even though approval might have just been certified. A recent estimate of the value of triazine products puts their value at $3 billion per year to agriculture, spread across the Cornbelt, and extending into sorghum and sugar cane regions of the US.
Your predecessors on your farm first began using atrazine in 1959, and it was the most widely used herbicide until recently overtaken by glyphosate. Numerous studies have been made of atrazine and its chemistry, the most recent study by agricultural economist Paul Mitchell of the University of Wisconsin. Mitchell’s study takes into account current corn production data, left out of prior reports, along with the economic impact of genetically modified corn and the increased dependence of the biofuel industry on corn. Mitchell adds that the recent issues surrounding glyphosate resistance in a dozen weed species increase the potential importance of atrazine as an alternative means of weed control.
Using all of these dynamics, Mitchell sets up a series of scenarios with and without the availability of atrazine to farmers and calculates the financial difference. For example he says if glyphosate is applied to 75% of corn acres, that would likely increase to as much as 100% if atrazine were not available.
Mitchell says one indicator of the value of atrazine is its widespread use, resulting from its low cost and effectiveness against many broadleaf weeds and grasses. He said USDA data indicated atrazine was used on 62% to 75% of corn acres between 1990 and 2005, declining only because of the introduction of glyphosate for corn. He says even when glyphosate was being applied to 75% of corn acreage in 2009, atrazine was being used on 57% of corn acres. Prior to glyphosate for corn, when 68% of acres were being treated with atrazine in 1991, the second most popular herbicide metolachlor was being used on only 20% of acreage.
If atrazine were unavailable for use, Mitchell says alternatives would be used and he based his value calculations on weed infestations, potential yield losses, herbicide efficacies, and crop potential in the various USDA production regions of the US. Based on yield data from other researchers, Mitchell computed a 20% yield loss without atrazine. Evaluating earlier reports, he said costs of additional herbicides were included, but not the time and machine cost of additional applications of herbicides. And he says because each field and farm are different, the cost is difficult to determine.