| Abstract
| - Soybean isoflavone concentrations vary widely, but the contribution of soil fertility and nutrientmanagement to this variability is unknown. Field experiments from 1998 to 2000 on soils with low tohigh exchangeable potassium (K) concentrations evaluated K application and placement effects onisoflavone concentrations and composition of soybean in various tillage and row-width systems.Soybean seed yield and concentrations of daidzein, genistein, glycitein, leaf K, and seed K weremeasured. Significant increases in daidzein, genistein, and total isoflavone were observed with directdeep-banded K or residual surface-applied K on low-K soils. Positive effects of K fertilization onisoflavones were less frequent on medium- to high-testing K soils. Both individual and total isoflavoneswere often positively correlated with seed yield, leaf K, and seed K on low-K soils. Appropriate Kmanagement could be an effective approach to increase isoflavone concentrations for soybeansproduced on low- to medium-K soils. Keywords: Potassium; soybean; Glycine max (L.) Merr.; isoflavone; daidzein; genistein; glycitein; yield;seed K; leaf K; correlation
|
