No-tillers should not be too quick to blame weather and the other usual culprits for struggling, diseased crops.
Don Huber, retired plant pathologist from Purdue University, says untreated micronutrient deficiencies may be to blame. Micronutrients are essential for small grains, soybeans, corn and other crops to tolerate stress, fight disease and produce to their potential.
Huber says the effects of micronutrient deficiencies are showing up more regularly, but it’s what’s he says is possibly causing those deficiencies that many no-tillers may find surprising — glyphosate.
“Glyphosate works by chelating — or tying up — micronutrients necessary for plant function. It even reduces micronutrient efficiency in glyphosate-tolerant crops,” he says. “Just having the gene present reduces efficiency up to 50% for zinc and manganese.
“Add the chemical to that and you get an additive effect on plant physiology, including decreased efficiency, stress and disease resistance.”
Most unexpected is that glyphosate is exuded by roots of weeds and glyphosate-resistant crops and lingers in the soil where it can impact crops in following years.
“Glyphosate is not bio-metabolized by the plant. It isn’t biologically degradable and it accumulates in the soil and in perennial plants,” Huber says. “It immobilizes rapidly because it’s a strong chelator, but it’s not removed from the system.”
Huber says glyphosate can create micronutrient deficiencies in three ways:
1. It reduces micronutrient utilization in glyphosate-tolerant crops due to a combination of the gene and the added effect of the chemical.
2. It lingers in the soil and in perennial…