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ARS Home » Midwest Area » Ames, Iowa » National Laboratory for Agriculture and The Environment » Agroecosystems Management Research » Research » Publications at this Location » Publication #422272
Research Project: Managing Nutrient, Carbon, and Water Fluxes to Provide Sustainable and Resilient Cropping Systems for Midwestern Landscapes

Location: Agroecosystems Management Research

Title: Long-term field study on corn response to sulfur fertilization in Iowa, USA

Author
item CRESPO, CECILIA - Oak Ridge Institute For Science And Education (ORISE)
item Kovar, John
item HART, CHAD - Iowa State University
item ROTH, RICHARD - Iowa State University
item O'Brien, Peter
item Ruis, Sabrina

Submitted to: Field Crops Research
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/14/2025
Publication Date: 5/19/2025
Citation: Crespo, C., Kovar, J.L., Hart, C.E., Roth, R.T., O'Brien, P.L., Ruis, S.J. 2025. Long-term field study on corn response to sulfur fertilization in Iowa, USA. Field Crops Research. https://doi.org/10.1016/j.fcr.2025.109990.
DOI: https://doi.org/10.1016/j.fcr.2025.109990

Interpretive Summary: Sulfur (S) is an essential plant nutrient that must be available to corn roots in order to achieve optimum growth of the plant. Our understanding of the benefits of S fertilizer for corn production in Iowa is limited. With a field study, we evaluated the performance of three S fertilizers applied at a single rate of 34 kg S/ha (30 lbs S/ac) as S sources for corn grown during 12 consecutive years in highly productive central Iowa soils. We found that S fertilizer increased S nutrition of the corn plants, especially in the early part of the growing season, but increased corn grain yield in only two of 12 (17%) study years. Measures of soil and plant tissue S failed as predictors of grain response to S fertilizer. Economic return from S fertilizer application was positive at current price levels when we accounted for the value of N in the fertilizer materials. The results of this research will benefit both commercial growers and the fertilizer industry by providing nutrient management guidelines that maximize crop utilization and yields.

Technical Abstract: Declines in atmospheric sulfur (S) deposition and S removal through continuous cropping have increased response to S fertilization in many crops. Still, responses to S fertilization by corn (Zea mays L.) grown in the Midwestern US have been inconsistent. We aimed to: (i) compare S source impacts on corn grain yield; (ii) evaluate soil extractable S, and plant S concentration at different growth stages as S diagnostic methods of corn S status; and (iii) explore the cost-effectiveness of various S sources under historical and current market price conditions. For 12 consecutive years, field experiments were conducted to evaluate corn response to three S sources (ammonium sulfate, ammonium thiosulfate, and gypsum) applied at 34 kg S/ha. Extractable soil S was measured before planting, and S concentration at V5, in ear leaf at mid-silk stage, and in grain were determined. Grain yield was evaluated at physiological maturity. Sulfur fertilization increased S concentration in 50% of years at V5, 33% at mid-silk, and 30% in grain. However, S fertilization increased grain yield in only two of 12 (17%) study years. Extractable S, soil organic matter, and S concentration in corn tissues failed as predictors of grain response to S. Economic return from S fertilization via ammonium sulfate and ammonium thiosulfate was positive at current price levels, after accounting for the value of N in the fertilizer. Overall, results from this 12-yr study showed S application may improve S content of the corn plant, but rarely grain yield, despite economic improvements.