Here Photo caption below Pathologist Don Huber says crops usually get enough phosphorus, potassium and other common minerals to grow, but often can't draw sufficient micronutrients from the soil to fend off diseases. Such nutrients include the metals manganese, copper, zinc, iron and boron. Symptoms aren't always apparent.
Micronutrients regulate a plant's physiology.
Not much micronutrient is needed to mobilize a plant's disease resistance, but it is critical. Soil composition is frequently overlooked in crop production, Huber says. Farmers and agronomists typically pay more attention to controlling insects and alien vegetation, or to weather forecasts. Huber suggests soil nutrition plays an equally important role in plant development. In studies at four Purdue agricultural research farms and at agronomy centers in Alberta, Canada, Huber and Canadian researchers found that micronutrient deficiencies have both a direct and indirect impact on crops.