The Effects of Establishment Methods and Fertilization Practices on Nitrate Leaching from Turfgrass

Abstract

AbstractA lysimeter study was conducted at the Ohio State University Turfgrass Research Center, Columbus, to investigate NO3‐N leaching losses from fertilized turfgrass. Nitrogen fertilizer treatments were applied to ‘Baron’ Kentucky bluegrass (Poa pratensis L.) seeded and sodded turf established on a Miamian silt loam (fine, mixed, mesic Typic Hapludalf). Treatments included two N sources, urea and resin‐coated urea (RCU); and Two fertilization programs, one that emphasize spring and summer applications (SSF) and the second program that included a late season application (LSF). Both the SSF‐ and LSF‐fertilization programs received 218.2 kg N ha−1 yr−1. The NO3‐N leachate concentrations from seeded turfgrass exceeded those from sodded turf for the first 3 mon. As the turf matured, NO3‐N losses from sod exceeded NO3‐N from the seeded plots. Leachate concentrations were 1.1 and 3.5 mg NO3‐N L−1 for seed and sod turf, respectively, from April 1990 through March 1991. Less rooting in the sodded plots resulted in greater N loss. Annual NO3‐N losses were not affected by N source. During the winter of 1991, significantly (P = 0.05) higher percolate NO3‐N concentrations were recorded from urea‐treated plots (3.66 mg NO3‐N L−1) vs. RCU (2.10 mg NO3‐N L−1), however. Similarly, N programs did not result in annual differences in percolate concentration, but differed during the winter of 1991. Concentrations were 3.37 and 2.39 mg NO3‐N L−1 for LSF and SSF, respectively. The NO3‐N leaching losses from all treatments exceeded the maximum concentration limit (MCL) early in the study. These high concentrations were caused by soil disturbance during establishment. During the 2nd yr, NO3‐N leaching results were more representative of typical turfgrass situations with mean annual flow‐weighted NO3‐N concentrations well below the MCL. Different N sources and fertilizer programs did not result in greater NO3‐N percolate losses compared to unfertilized turfgrass plots.