TITLE:
Soybean Seed Protein, Oil, Fatty Acids, and Isoflavones Altered by Potassium Fertilizer Rates in the Midsouth
AUTHORS:
Nacer Bellaloui, Xinhua Yin, Alemu Mengistu, Angela M. McClure, Don D. Tyler, Krishna N. Reddy
KEYWORDS:
Fatty Acids; Isoflavones; Oil; Oleic Acid; Potassium Fertilizer; Protein; Seed Composition
JOURNAL NAME:
American Journal of Plant Sciences,
Vol.4 No.5,
May
29,
2013
ABSTRACT: Previous research has shown that the effect of potassium
fertilizer on soybean ([Glycine max (L.) Merr.] seed composition (protein, oil, fatty acids,
and isoflavones) is still largely unknown. Therefore, the objective of this
research was to investigate the effects of potassium application on seed
protein, oil, fatty acids, and isoflavones under Midsouth environmental conditions. A three-year
experiment was conducted in two locations (Milan, TN and Jackson, TN). Potassium (K) rates were applied in the
form of K2O at a rate of 0 (Control, C), 45 (T1), 90 (T2), 134 (T3),
and 179 (T4) kg·ha-1 in a randomized complete
block design. The results showed that increasing the K application rate did not
result in consistent effects on yield. However, increasing K application rate
did increase protein, oleic acid, and individual and total isoflavone
concentrations at both locations in 2008 and 2009. In Jackson in 2010, the increase of K rate did
not change oleic acid, but resulted in an increase in glycitein and genistein
isoflavone concentrations. In 2010, increasing K application rate increased
protein concentrations, decreased individual and total isoflavones, and did not
change oleic acid concentration at Milan.
At the highest rate of K, 179 kg·ha-1, yield and some seed composition
constituents were negatively impacted. Generally, K concentration in leaves at
V5, R1, R3, and seed at harvest maturity stage (R8) increased with the increase of K rate applications. The research
demonstrated that K application can alter seed composition, but this alteration depended on location, environmental stress factors, mainly heat and drought, K level in soil, and K
application rate. Higher
rates of K application may negatively impact seed composition constituents.