Skip to main content
ARS Home » Southeast Area » Stoneville, Mississippi » Crop Genetics Research » Research » Publications at this Location » Publication #300772
Title: Effect of foliar and soil application of potassium fertilizer on soybean seed protein, oil, fatty acids, and minerals

Author
item PANDE, MANJU - Mississippi Valley State University
item GOLI, MUDLAGIRI - Mississippi Valley State University
item Bellaloui, Nacer

Submitted to: American Journal of Plant Sciences
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/19/2014
Publication Date: 3/1/2014
Citation: Pande, M., Goli, M.B., Bellaloui, N. 2014. Effect of foliar and soil application of potassium fertilizer on soybean seed protein, oil, fatty acids, and minerals. American Journal of Plant Sciences. 5:541-548.

Interpretive Summary: Potassium is an essential nutrient for crop growth, production, and seed quality. Although potassium fertilizer can be applied to soil, foliar application may rapidly correct potassium deficiency, especially under stress conditions of heat and drought. Whether soil or foliar potassium application is more effective for improving soybean seed composition (protein, oil, fatty acids, and mineral nutrition) is not yet known. In a study to evaluate the effectiveness of soil and foliar application of potassium on seed composition results obtained from greenhouse experiment showed that foliar application resulted in higher potassium, sulfur, and sodium concentrations in leaves compared with the soil application, and the concentrations of potassium and sodium increased with the rate of potassium application. Generally, both soil and foliar application resulted in higher seed protein, but the increase of protein sometimes resulted in lower oil. Seed palmitic acid (saturated fatty acid) and oleic acid (desirable fatty acid) were higher at higher rate of potassium when applied foliarly, but linolenic acid (unsaturated fatty acids) was higher at higher rate of potassium applied to soil. The research demonstrated that the type and the rate of potassium fertilization can alter seed composition, especially seed protein, oil, and palmitic acid. This information is beneficial for growers and agronomists to optimize potassium fertilization management for higher seed quality. Further research is needed to evaluate the effectiveness of the type and rate of potassium fertilizers under field conditions.

Technical 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 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 T1and 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 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 of (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.