Urea cocrystals as a potential fertilizer for turfgrass: responses of a hybrid bermudagrass and nitrogen release behavior

Authors: Hejl, Reagan; Stiles, Julia; BALTRUSAITIS, JONAS - Lehigh University; Williams, Clinton; EISA, MOHAMED - Lehigh University; RAGAUSKAITE, DOVILE - Lehigh University; Serba, Desalegn

Submitted to: HortTechnology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/4/2024
Publication Date: 7/18/2024
Citation: Hejl, R.W., Stiles, J.F., Baltrusaitis, Jonas, Williams, C.F., Eisa, Mohamed, Ragauskaite, Dovile, Serba, D.D. 2024. Urea cocrystals as a potential fertilizer for turfgrass: responses of a hybrid bermudagrass and nitrogen release behavior. HortTechnology. 34(4):474-480. https://doi.org/10.21273/HORTTECH05423-24.
DOI: https://doi.org/10.21273/HORTTECH05423-24

Interpretive Summary: Decreasing environmental losses of nitrogen fertilizers is important for sustainable fertility programs in agriculture and turfgrass management. Urea cocrystals are a potential fertilizer source offering decreased losses; however, to date have not been tested in turfgrass systems. A greenhouse study was conducted to evaluate the response of a bermudagrass to two newly-developed cocrystal products compared to two traditional urea products supplied at two rates. A companion experiment was also conducted to evaluate nitrogen release and environmental loss potential through leaching of the cocrystal products compared to urea. In the turfgrass response study conducted in the greenhouse, improved turfgrass quality from application of the cocrystal products was most apparent in the summer study in which visual quality ratings were improved during the study period and were significantly higher for both cocrystal products in the later weeks of the study. For normalized difference vegetation index (NDVI), cocrystal UC2 (Ca(H2PO4)2·4urea) outperformed all other products in the summer study and both cocrystal products outperformed MUPCU (Methylene urea, urea, polymer-coated urea) in the winter study. Further, both cocrystal products showed favorable growth responses compared to the commercial products provided by positive clipping production and vertical extension rates. In the nitrogen release experiment, a rapid water release test revealed the N release peak of urea was significantly higher than both UC1 and UC2. Furthermore, significantly higher N was leached from urea (15% loss) compared to both UC1 and UC2 (˜8% loss). Results from both studies provide evidence supporting suitability of urea cocrystal application on bermudagrass and potential as a slow-release fertilizer source through sustained visual quality, turfgrass vigor, growth, decreased N release peak, and decreased leaching losses.

Technical Abstract: Urea cocrystals materials are a potential fertilizer source that has shown to decrease environmental nitrogen losses. Novel nitrogen (N) containing fertilizers were synthesized using the mechanochemical method to form stable urea cocrystals to be tested as a fertilizer source for turfgrass. The objectives of this study were to 1) evaluate the response of ‘Tifway’ bermudagrass (Cynodon dactylon × C. traansvalensis Burt Davy) to nitrogen (N) fertilization by urea cocrystals and traditional coated urea products supplied at two rates at the beginning of two, ten-week study periods conducted in a greenhouse and 2) investigate N release behavior of urea and two cocrystal products using a rapid water release test. In the turfgrass response study conducted in the greenhouse, improved turfgrass quality from application of the cocrystal products was most apparent in the summer study in which visual quality ratings were improved during the study period and were significantly higher for both cocrystal products in the later weeks of the study. For normalized difference vegetation index (NDVI), cocrystal UC2 (Ca(H2PO4)2·4urea) outperformed all other products in the summer study and both cocrystal products outperformed MUPCU (Methylene urea, urea, polymer-coated urea) in the winter study. Further, both cocrystal products showed favorable growth responses compared to the commercial products provided by positive clipping production and vertical extension rates. In the nitrogen release experiment, a rapid water release test revealed the N release peak of urea was significantly higher than both UC1 and UC2. Furthermore, significantly higher N was leached from urea (15% loss) compared to both UC1 and UC2 (˜8% loss). Results from both studies provide evidence supporting suitability of urea cocrystal application on bermudagrass and potential as a slow-release fertilizer source through sustained visual quality, turfgrass vigor, growth, decreased N release peak, and decreased leaching losses.