Nitrous Oxide Emissions from a Golf Course Fairway and Rough after Application of Different Nitrogen Fertilizers

Few studies have quantified nitrous oxide (NO) emissions from intensively managed turfgrass systems on golf courses. Fertilizer treatments consisting of urea with inhibitors of nitrification and urease (INU), polymer-coated urea (PCU), and uncoated balanced methylene urea (BMU) chain, which use different mechanisms to control the release of N substrate, were applied to a golf course fairway and rough three times during the 2011 growing season at a rate of 50 kg N ha per application. The vented chamber method was used to measure turf-soil-atmospheric NO exchange. Cumulative emissions from fairway INU, PCU, and BMU treatments totaled 6.5, 1.9, and 7.6 kg NO-N ha yr, representing a 4.02, 1.25, and 4.75% loss of total N applied, respectively. Summer INU and BMU fertilization to the fairway produced the greatest NO fluxes. Rapid fluxes during the summer were likely related to low physiological activity in cool-season turfgrass and to warm, wet soil conditions that increased denitrification rates. However, PCU applied to the fairway was more resistant to NO losses than other fertilizer treatments. Fertilizer treatments applied to the rough had cumulative emissions of 2.4, 1.50, and 1.49 kg NO-N ha yr from INU, PCU, and BMU treatments, corresponding to a 1.21, 0.62, and 0.61% loss of total N applied, respectively. The lower NO emission on roughs was likely associated with greater carbon pools, lower soil moisture, and lower temperatures. This study supports the effectiveness of PCU to reduce NO emission from cool-season turfgrass fairways when soil conditions favored denitrification during warm periods. Applying INU and BMU when soil was cool and dry was effective in moderating NO losses.