Kansas State Researchers’ Breakthrough Boosts Soybean Disease Defense with Phosphorus

By Trish Svoboda

Researchers at Kansas State University are advancing efforts to combat a severe fungal disease that impacts soybean production. They have recently achieved a breakthrough by demonstrating the efficacy of elevated phosphorus levels in disease management.

K-State plant pathologist Rodrigo Onofre and agronomist Eric Adee have spent several years studying the impact of adding varying rates of phosphorus, nitrogen and potassium to fertilizer in order to combat Sudden Death Syndrome (SDS), a soil-borne, fungal pathogen that invades the roots and lower stem of the soybean plant.

SDS, initially detected in the U.S. in 1971 in Arkansas, has since spread to multiple states across the central region. It was first documented in Kansas in 1993, and according to a report by the United Soybean Board, SDS results in significant annual economic losses totaling millions of dollars in the state.

According to the K-State study, nitrogen and potassium did not provide a detectable defense against SDS. However, Onofre noted that a combination of nitrogen and phosphorus appeared to enhance the crop’s yield.

The study at K-State concentrated on applying fertilizer in fields rotated between corn and soybeans. Fertilizer application occurred before planting corn. Researchers added phosphorus to fertilizer at three different rates—zero, 30, and 60 pounds per acre. Onofre said that 60 pounds per acre was the rate that most reduced disease.

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