March 12, 2021
Boron (B) is an important micronutrient. It is used by the corn plant for sugar translocation and carbohydrate metabolism. It also plays a factor in pollen development and seed set.
The primary source of B is soil organic matter. It becomes available as the organic matter decomposes. Deficiencies are typically rare in corn. When it does occur, it is most commonly found on coarse textured soils with low organic matter. Because B availability falls as soil pH levels get above 7, deficiency symptoms may appear in high pH soils or fields that were recently limed (Figure 1).
Deficiency symptoms include misshapen or abnormal growth of the young leaves (Figure 2). Symptoms tend to be evident in the youngest leaves because boron is not very mobile within the corn plant. Affected plants may produce ears that are barren or have poor kernel development.
Soil test and plant tissue tests can be helpful in diagnosing B deficiency. If supplemental B is needed, it is important to determine the proper rate and application method to meet the B needs of your field. Boron can be broadcast with dry fertilizer, applied as a foliar spray, or included in some starter fertilizer applications. Since B can injure germinating seeds, it should not be placed in close contact with the seed.
Consult with your local extension service or agronomist for more information.
Figure 1. Boron deficiency in corn showing symptoms of abnormal growth on the youngest leaves. Picture courtesy of IPNI, J.E. Espinosa.
Figure 2. Nutrient availability based on soil pH. Illinois Agronomy Handbook. Permission for use granted by Dr. Emerson Nafziger, University of Illinois.
Sources
Mallarino, A., Enderson, J., and Haq, M. 2014. Corn and soybean yield response to micronutrients fertilization. Iowa State University. Integrated Crop Management Conference. - https://lib.dr.iastate.edu/.
Lentz, E. and Culman, S. 2014. Micronutrients in starter fertilizer for corn. The Ohio State University Agronomic Crops Network. Ohio State University Extension. https://agcrops.osu.edu.
Mengel, D. 1990. Role of micronutrients in efficient crop production. Agronomy Guide. AY-239. Purdue University Cooperative Extension Service. https://www.extension.purdue.edu.
Nutifafa,A., and Yin, F. 2020. Does boron fertilizer increase corn and soybean yields? UTcrops News Blog. University of Tennessee Institute of Agriculture. The University of Tennessee. https://news.utcrops.com/.
Sutradhar, A.K., Kaiser, D.E., and Rosen, C.J. 2016. Boron for Minnesota soils. University of Minnesota Extension. https://extension.umn.edu/.