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ARS Home » Pacific West Area » Maricopa, Arizona » U.S. Arid Land Agricultural Research Center » Water Management and Conservation Research » Research » Publications at this Location » Publication #405801
Research Project: Increasing the Utility of Turf in Urban Environments of the Southwest U.S.

Location: Water Management and Conservation Research

Title: Evaluation of spent coffee grounds as a nutrient source for turfgrass

Author
item FLORES, GARRETT - Scythe Robotics Inc
item WHERLEY, BENJAMIN - Texas A&M University
item MCINNES, KEVIN - Texas A&M University
item FEAGLEY, SAM - Texas A&M University
item Hejl, Reagan

Submitted to: Journal of Plant Nutrition
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/10/2024
Publication Date: 7/16/2024
Citation: Flores, G., Wherley, B., McInnes, K., Feagley, S., Hejl, R.W. 2024. Evaluation of spent coffee grounds as a nutrient source for turfgrass. Journal of Plant Nutrition. https://doi.org/10.1080/01904167.2024.2380488.
DOI: https://doi.org/10.1080/01904167.2024.2380488

Interpretive Summary: Spent coffee grounds are a by-product in the production process of cold-brewed coffee. Spent coffee grounds may contain favorable agronomic properties and due to increased popularity of cold-brewed coffee, a greater abundance of the by-product is available. While information is available examining the effects of spent coffee grounds on plants, little information is available pertaining to turfgrass systems. A two-year field study was conducted to evaluate the agronomic feasibility of using spent coffee grounds as a nutrient source for turfgrass. In the study, the performance of a turf-type bermudagrass was characterized while receiving multiple nutrient sources including fresh and composted spent coffee grounds, as synthetic, natural organic, and bridge fertilizers, some of which contained spent coffee grounds. Soils were analyzed at the conclusion of the study to determine whether spent coffee grounds provided long-term effects of on soil pH and/or nutrient concentrations. The application of spent coffee grounds in the study did not produce similar responses as a typical fertilizer. However, when combined with poultry litter, the spent coffee cround-containing organic fertilizer GeoJava produced improved turf quality relative to other organic and synthetic commercial fertilizers in our study. Also, the repeated application of spent coffee grounds did not result in long-term changes to soil pH. Although early on, spent coffee ground treatments caused some phytotoxicity, these effects were not observed when it was applied in combination with the manure used in GeoJava.

Technical Abstract: The growing popularity of cold-brewed coffee has resulted in large amounts of localized spent coffee grounds (SCG) generated from production plants. Spent coffee grounds offer many favorable agronomic properties, but also contain caffeine, tannins and phenolic compounds that may be deleterious to plant growth. There is a growing body of research examining the effects of SCG on plants, but little of which pertains to use in turfgrass systems. The objective of this two-year field study was to evaluate the feasibility of using SCG as an agronomic source of nutrients for turfgrass. Field studies were conducted over two years to characterize performance of ‘Riley’s Super Sport’ (CelebrationVR) bermudagrass (Cynodon dactylon) receiving multiple nutrient source treatments including fresh and composted SCG, as well as synthetic, natural organic, and bridge fertilizers, some which included SCG. Soils were analyzed at the conclusion of the study to determine whether SGC provided long-term effects of on soil pH and/or nutrient concentrations. Our results demonstrated that although SCG possesses between 2.3-2.9% N and a favorable C:N ratio, direct SCG applications over two seasons did not produce responses typical of a fertilizer when applied as a topdressing. However, when combined with poultry litter, the SCG-containing organic fertilizer GeoJava produced improved turf quality relative to other organic and synthetic commercial fertilizers in our study, including Milorganite, ammonium sulfate, and URI-PEL S.R. Further, despite the acidic nature of SCG, their repeated application over multiple years did not result in any long-term changes to soil pH. Although early on, SCG treatments caused mild and transient phytotoxicity, these effects were not observed when it was applied in combination with the manure used in GeoJava.