Fate and Transport of Nitrogen Applied to Six Warm‐Season Turfgrasses

Abstract

A greenhouse study compared six warm season turfgrasses {common bermudagrass [Cynodon dactylon (L.) Pers.], ‘Tifway’ hybrid bermudagrass (C. dactylon × transvaalensis), centipedegrass (Eremochloa ophiuroides (Munro) Hack.), ‘Raleigh’ St. Augustinegrass [Stenotaphrum secundatum (Walter) Kuntze], ‘Meyer’ zoysiagrass (Zoysia japonica Steud.), and ‘Emerald’ zoysiagrass (Z. japonica × tenuifolia)] for NO3‐N leaching and N use efficiency. Sod was established in sand‐filled columns and managed under worst‐case conditions to promote nitrate leaching. Ammonium nitrate was applied at 50 kg N ha−1 on seven dates, with the final application labeled with 15N. Leachate samples were collected and analyzed for NO3‐N and NH4‐N and clippings were analyzed for total N. Leaching losses were high following the first N application, ranging from 48 to 100% of the NO3‐N and 4 to 16% of the NH4‐N applied. Nitrate loss from subsequent applications was reduced substantially, while NH4 leaching was essentially eliminated. There were significant differences among species for leachate NO3‐N concentration and cumulative N leached, with St. Augustinegrass being the most effective and Meyer zoysiagrass the least effective at minimizing NO3 leaching. Nitrogen recovery by the turf ranged from 63% for Meyer zoysiagrass to 84% for hybrid bermudagrass. Root length density (RLD) varied significantly among species at depths >30 cm, and was negatively correlated with NO3 leaching loss. These results document differences between the warm season turfgrasses for NO3 leaching potential, possibly related to root distribution, and emphasize that species selection is an important factor in minimizing environmental impacts from turfgrass management.