Does Nitrogen Source Influence Zoysiagrass Growth?

Despite zoysiagrass (Zoysia spp.) having modest responses to nitrogen (N) fertilization, especially during establishment (Richardson et al., 2001), no information about the preference for mineral form is available. Nitrogen source has been documented to influence growth in creeping bentgrass (Agrostis stolonifera) and annual bluegrass (Poa annua) (Glinski et al., 1990; Schlossberg and Schmidt, 2007). Fertilizing with the majority of N as nitrate improved growth and rooting of creeping bentgrass (Glinski et al., 1990), whereas annual bluegrass+bentgrass preferred applications with the majority of N as ammonium (Schlossberg and Schmidt, 2007). To date, no one has examined the affect of urea:nitrate ratio on zoysiagrass leaf growth, color, and rooting, but an anecdotal report found that urea and ammonium sulfate resulted in superior shoot growth compared to ammonium nitrate (Hwang et al., 1991), suggesting that zoysiagrass may favor ammonium and urea N sources. Fertilizing zoysiagrass with the appropriate urea:nitrate N source could lead to reduced N inputs. A greenhouse study was conducted with the objective to determine how nitrogen source affects the growth and rooting of zoysiagrass cultivars.