title: Potassium fertilization effects on isoflavone concentrations in soybean [Glycine max (L.) Merr.].
abstract: Soybean isoflavone concentrations vary widely, but the contribution of soil fertility and nutrient management to this variability is unknown. Field experiments from 1998 to 2000 on soils with low to high exchangeable potassium (K) concentrations evaluated K application and placement effects on isoflavone 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 were measured. Significant increases in daidzein, genistein, and total isoflavone were observed with direct deep-banded K or residual surface-applied K on low-K soils. Positive effects of K fertilization on isoflavones were less frequent on medium- to high-testing K soils. Both individual and total isoflavones were often positively correlated with seed yield, leaf K, and seed K on low-K soils. Appropriate K management could be an effective approach to increase isoflavone concentrations for soybeans produced on low- to medium-K soils.
authors.affiliation: Department of Agronomy, Purdue University, 1150 Lilly Hall, West Lafayette, Indiana 47907-1150, USA. tvyn@purdue.edu
authors.forename: Tony J
authors.initials: TJ
authors.lastname: Vyn
authors.forename: Xinhua
authors.initials: X
authors.lastname: Yin
authors.forename: Tom W
authors.initials: TW
authors.lastname: Bruulsema
authors.forename: Chung-Ja C
authors.initials: CJ
authors.lastname: Jackson
authors.forename: Istvan
authors.initials: I
authors.lastname: Rajcan
authors.forename: Sylvie M
authors.initials: SM
authors.lastname: Brouder
mesh_terms: D000383:Agriculture; D005308:Fertilizers; D019833:Genistein / Q000032:analysis; D007529:Isoflavones / Q000032:analysis*; D018515:Plant Leaves / Q000737:chemistry; D011188:Potassium / Q000032:analysis / Q000494:pharmacology*; D012639:Seeds / Q000737:chemistry; D012987:Soil / Q000032:analysis; D013025:Glycine max / Q000737:chemistry*
chemical_list: D005308:Fertilizers; D007529:Isoflavones; D012987:Soil; C004742:daidzein; C086566:glycitein; D019833:Genistein; D011188:Potassium