Sulfur availability minimizes nitrate leaching losses in vulnerable agricultural soils

Abstract

Despite the critical need for nitrogen (N) in cropping systems, excessive N fertilizer application has severe environmental consequences. The synergistic interaction between sulfur (S) and N in plant nutrition could be exploited to increase N utilization, thereby maximizing N recovery and reducing losses. In a three-year study at six locations across three countries (USA, Ghana, and Mali), we evaluated the effect of S availability on N leaching losses from N fertilizer application using corn as the study crop. The study consisted of three S sources (micronized elemental sulfur [MES], untreated elemental sulfur [ES], and ammonium sulfate [AS]); five S application rates [(i) site-specific recommended S rate (SR), (ii) ¼ of the recommended S rate (25%_SR) (iii) ½ of the recommended S rate (50%_SR), (iv) ¾ of the recommended S rate (75%_SR); and (v) 1¼ of the recommended S rate (125%_SR)]; and a single N application rate (site-specific recommended N rate). Regardless of the S source, N recovery progressively increased with increasing S application rate. For the AS and MES sources, leachate nitrate concentration from the treatments with S application ≥ SR was statistically similar to that of the background concentrations, and the highest concentrations occurred with the treatment with no S application. Thus, for environmental stewardship, a critical look into S application in cropping systems is a necessity due to its synergistic interaction with N. In addition to improving productivity and enhancing efficient recovery of applied N fertilizers, S availability will minimize nitrate leaching commonly associated with application of N fertilizers.

Keywords:

• Ammonium sulfate
• apparent nitrogen recovery efficiency
• corn yield
• micronized elemental sulfur
• nitrogen use efficiency
• sulfur application rate

Acknowledgements

We thank Alhaji Rahman Issahaku, and Albert B. Angzenaa, formerly of the International Fertilizer Development Center (IFDC), for their technical support. We thank Judith Fagbegnon-Kodjo of IFDC for administrative and logistic support. We are grateful to Emmanuel K.M. Vorleto of Savanna Agricultural Research Institute and Sammy Afful of the Ghana Atomic Energy Commission’s analytical lab for soil and plant tissue analyses. We also wish to express our deepest appreciation to Joaquin Sanabria for overseeing the statistical analysis, review and constructive criticism.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

Funding for this work was provided in part by the USDA- Agricultural Research Service National Program 216 (Sustainable Agricultural Systems Research), and the United States Agency for International Development’s Feed the Future Soil Fertility Technology Adoption, Policy Reform, and Knowledge Management project.