Effect of different nutrient levels on the resistance of soybean to Macrophomina phaseolina infection in field experiments

Abstract

Field experiments were carried out with soybean [Glycine max (L.) Merrill] on a Haplic Chernozem soil. Eleven treatment combinations were applied with increasing rates of fertilizers in three replicates. At full maturity the dry weight production, total biomass production, root weight, yield, shoot NPK concentration and severity of Macrophomina phaseolina infection were determined. The highest degree of Macrophomina infection was found in the lowest NPK treatment, while the lowest rate of disease was observed for the highest NPK combination. By increasing the NK supply, the degree of infection decreased. At the same fertilizer rates, significantly lower infection was observed at higher phosphorus levels. The dry weight production, total biomass production of the shoots, pod weight and nitrogen concentration of the shoots were negatively correlated with the rate and severity of infection, which was positively correlated with the concentration of phosphorus. No correlation was found between root weight and infection or between potassium concentration and infection. © 2008 Akadémiai Kiadó.