Sulfur availability minimizes nitrate leaching losses in vulnerable agricultural soils

Authors: Agyin-Birikorang, Sampson; BOUBAKRY, C - International Crops Research Institute For The Semi-Arid Tropics (ICRISAT); KADYAMPAKENI, DAVIE - University Of Florida; ADU-GYAMFI, RAPHAEL - University For Development Studies; Chambers, Rachel; TINDJINA, IGNATIUS - International Fertilizer Development Center (IFDC); FUSENI, ABDUL-RAHMAN - International Fertilizer Development Center (IFDC)

Submitted to: Journal of Plant Nutrition
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/7/2024
Publication Date: 5/16/2024
Citation: Agyin-Birikorang, S., Boubakry, C., Kadyampakeni, D.M., Adu-Gyamfi, R., Chambers, R.A., Tindjina, I., Fuseni, A.A. 2024. Sulfur availability minimizes nitrate leaching losses in vulnerable agricultural soils. Journal of Plant Nutrition. 47(15):2389-2405. https://doi.org/10.1080/01904167.2024.2354171.
DOI: https://doi.org/10.1080/01904167.2024.2354171

Interpretive Summary: Despite the critical need for nitrogen (N) in cropping systems, excessive N fertilizer application has severe environmental consequences including leaching losses to contaminate groundwater resources. 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 (Zea mays L.) 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), 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 (the site-specific recommended N rate). The agronomic effectiveness of the S sources followed the order: AS=MES>ES, and that of the S rate followed the order: 125%_SR=SR=75%_SR>50%_SR>25%_SR>control. Apparent N recovery efficiency (ANRE) progressively increased with the increasing rate of S application. For the AS and MES sources, the concentration of nitrate in the extracted water from the treatments with an S rate (=SR) was statistically similar to the background concentrations, and the highest nitrate concentrations occurred with the treatment with no S application. Thus, for production cost reduction, and environmental stewardship, a critical look into S application in cropping systems is a necessity. In addition to improving productivity and enhancing efficient recovery of applied N fertilizers, S availability will minimize nitrate leaching commonly associated with the application of N fertilizers in cropping systems.

Technical Abstract: Given the serious food security challenges to meet the current and future food demands, the best agricultural management strategies to improve crop productivity will always involve the application of additional essential nutrients to augment the native soil supply. Nitrogen (N), one of such essential plant nutrients is required in large quantities for crop production, and it is considered an important commodity for agricultural systems because it is involved in many crucial physiological processes. However, despite the critical need for nitrogen (N) in cropping systems, excessive N fertilizer application has severe environmental consequences including leaching losses to contaminate groundwater resources. 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. We hypothesized that S availability could enhance the absorption and utilization of N in plants, which will reduce residual N concentration of the soil following N fertilizer application and ultimately lead to minimal NO3- leaching 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 (Zea mays L.) as the study crop. The overall objective of this study was, therefore, to evaluate the effect of S availability on N leaching losses from applied N fertilizer sources in crop production systems. Specific objectives were to assess S availability on (i) corn yield, (ii) N recovery efficiency, and (iv) NO3- leaching from the soil following N fertilizer application. 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), 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 (the site-specific recommended N rate). The agronomic effectiveness of the S sources followed the order: AS = MES > ES, and that of the S rate followed the order: 125%_SR = SR = 75%_SR > 50%_SR > 25%_SR > control. Apparent N recovery efficiency progressively increased with the increasing rate of S application. For the AS and MES sources, the concentration of nitrate in the extracted water from the treatments with an S rate (= SR) was statistically similar to the background concentrations, and the highest nitrate concentrations occurred with the treatment with no S application. Thus, for production cost reduction, and environmental stewardship, a critical look into S application in cropping systems is a necessity. In addition to improving productivity and enhancing efficient recovery of applied N fertilizers, S availability will minimize nitrate leaching commonly associated with the application of N fertilizers in cropping systems.