TITLE:
Effect of Foliar and Soil Application of Potassium Fertilizer on Soybean Seed Protein, Oil, Fatty Acids, and Minerals
AUTHORS:
Manju Pande, Mudlagiri B. Goli, Nacer Bellaloui
KEYWORDS:
Potassium; Soybean; Seed Minerals; Seed Composition; Foliar Application
JOURNAL NAME:
American Journal of Plant Sciences,
Vol.5 No.5,
March
7,
2014
ABSTRACT:
The objective of this research was to evaluate
the effectiveness of soil and foliar application of potassium (K) on leaf and
seed mineral concentration levels, and seed composition (protein, oil, fatty
acids, and minerals). Soybean cultivar (Pioneer 95470) of maturity group 5.7
was grown in a repeated greenhouse experiment in a randomized complete block
design. Treatment consisted of two concentrations of foliar K application (T1,
rate of 1.75% and T2, rate of 2.5%) and soil application (T3, rate of 190 mg/kg
and T4, rate of 380 mg/kg). Potassium was applied for each type at V3
(vegetative) and R3 (beginning of seed pod initiation) stages. The results
showed higher K and S concentrations in leaves in T1 and T2. The concentrations
of B and Zn decreased in all treatments, whereas Fe concentration increased in
T1 and T3. In seeds, most
mineral concentrations were stable, except for Fe which increased in both T1
and T3. Seed protein percentage increased 3.0% in T3 compared with the control
(no K application). Seed oil percentage showed a general decrease in all the
treatments, except for 3.2% increase in T4. Palmitic acid percentages showed
significant increase in all concentrations, the highest percentage increase of
16.9% was observed in T4. Stearic acid increased in T2 and T3. Linoleic acid
percentages increased in both foliar treatments, but linolenic acid percentage
increased in high soil treatment T4 alone, with an increase of 12.2% in
comparison to the control. Significant decrease (15.8%) in linoleic acid was
found in foliar application, T2. Oleic acid decreased uniformly in all
treatments, where the highest decrease (19.2%) was observed in soil
application, T4. Our research demonstrated that both foliar and soil
application of K were found to selectively alter seed composition. Further
research is needed to be conducted under field conditions before conclusions
can be made.