Impacts of nitrogen fertilization on hybrid bermudagrass during deficit irrigation

Authors: Hejl, Reagan; Conley, Matthew; Stiles, Julia; Serba, Desalegn; Williams, Clinton

Submitted to: Grasses
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/30/2025
Publication Date: 6/13/2025
Citation: Hejl, R.W., Conley, M.M., Stiles, J.F., Serba, D.D., Williams, C.F. 2025. Impacts of nitrogen fertilization on hybrid bermudagrass during deficit irrigation. Grasses. 4(2). Article 25. https://doi.org/10.3390/grasses4020025.
DOI: https://doi.org/10.3390/grasses4020025

Interpretive Summary: Nitrogen fertilization is an important aspect of turfgrass management; however, more information is needed on how nitrogen applications impact important factors such as water use and performance of hybrid bermudagrass during different irrigation scenarios. Two 7-week studies were carried out in greenhouses to evaluate responses of ‘TifTuf’ hybrid bermudagrass to three fertilizer rates and three irrigation levels. Irrigation treatments included a well-watered treatment and two irrigation deficit treatments (0.65 or 0.30 × ETa) while fertilizer was either withheld or applied monthly at two rates (4.8 g N m-2 or 2.4 g N m-2). While fertilizer application increased water use by 11-12%, it also improved overall turfgrass visual quality, water use efficiency, and clipping production compared to the unfertilized turfgrass. In comparison of the two fertilizer treatments, there were generally greater benefits observed at the higher application rate. While both fertilizer treatment levels improved visual quality at the moderate irrigation deficit level, the higher application rate produced improved visual quality at the more severe irrigation deficit level. Fertilizer application did not an impact on root development, but root development was hindered at the lowest irrigation deficit level. The results from this study indicate nitrogen fertilization enhances important aspects for maintaining a healthy turfgrass systems; however, important considerations must be made to navigate water conservation and ecosystem service preservation.

Technical Abstract: Limited information is available detailing the impact of nitrogen management on performance and actual plant evapotranspiration (ETa) of hybrid bermudagrass in both well-watered and deficit irrigation scenarios. In this study, two 7-week experiments were carried out in greenhouses to evaluate responses of ‘TifTuf’ hybrid bermudagrass (Cynodon dactylon × C. traansvalensis Burt Davy) to three fertilizer rates and three irrigation levels. Irrigation treatments included a well-watered treatment (1.0 × ETa) and two deficit treatments (0.65 or 0.30 × ETa) while fertilizer was either withheld or applied monthly at two rates (4.8 g N m-2 or 2.4 g N m-2). During the study period, 11-12% greater ETa was observed for turfgrass receiving fertilizer applications compared to unfertilized turfgrass with no significant differences in ETa between the two fertilizer rates. For well-watered treatments, turfgrass receiving the higher monthly fertilizer rate exhibited significantly increased turfgrass visual quality across the study period compared to both the unfertilized control and turfgrass receiving the monthly low rate. Fertilizer application at either rate improved visual quality at the mild deficit irrigation level (0.65 × ETa), and the high application rate produced increased visual quality values at the moderate deficit level (0.30 × ETa). Soil sampling revealed elevated nitrate-N for the high-rate fertilizer treatment while shoot sampling showed increased nitrogen assimilation with increased fertility. Fertilizer application also resulted in increased clipping production and water use efficiency (WUE). While fertilizer did not impact root dry weight, hindered root development at the moderate (0.30 × ETa) deficit irrigation level was observed. The results from this study indicate N fertilization enhances visual quality, shoot production, water use efficiency, and tolerance to deficit irrigation; however, trade-offs such as increased water use and potential nutrient loss due to elevated nitrate-N levels which should be consciously controlled for water conservation purposes and ecosystem service preservation.