Trace Gas Fluxes From Colorado Golf Courses.

Trace Gas Fluxes from Colorado Golf Courses The additions of nitrogen fertilizers have been recognized as a way to increase C sequestration. However, nitrogen fertilizer emits nitrous oxide (N2O) an important GHG that degrades ozone and is 300 times more powerful than CO2. The atmospheric N2O stock is increasing at nearly 5 billion tons of nitrogen per year and while estimates are not completely certain of the specific sources of emissions, it is estimated that nearly 80% of N2O pollution comes from anthropogenic sources. Turf in Colorado is a major industry that covers a total area of over 35,000 acres. Globally it is estimated that there are 32,000 golf courses in the world. Historically turfgrass emissions were considered negligible, but the rapid expansion of fertilized and irrigated urban area may have important social and environmental impacts. Therefore urban areas may be representing an unacknowledged, but substantial source of atmospheric N2O. The advancements in fertilizer technology suggest that slow release types may restrict N2O emissions by reducing environmental losses and increased nutrient availability. It has been reported that nitrification inhibitor and polymer coated fertilizers have significantly reduced N2O emissions. However, due to some contradictions in the literature, more research is needed. In 2011 trace gas emissions plots were established near Timnath, CO on the Harmony Golf Club fairway, rough, native areas and nursery greens. Trace gas samples were taken biweekly in the summer, twice per month in the fall and winter, and weekly during the spring. Fertilizer treatments of POLYON, BCMU, UMAXX and a control were established in triplicate on fairways and roughs, while native sites received no treatment and greens were managed by the superintendent. UMAXX has a nitrification urease inhibitor and POLYON and BCMU are heavy coated and light coated polyurethane types, respectively. Spring, summer and fall fertilizer applications of 50 kg/ha were applied to the fairway and rough, totaling 150 kg/ha for the year. Fairways had significantly higher N2O emission compared to roughs, native areas or nursery greens. On the fairway there were significant differences between fertilizer types. On the fairway BCMU had cumulative N2O fluxes of 7.8 kg ha -1 and was significantly higher compared to the control and POLYON. UMAXX had N2O fluxes 5.45 kg ha -1 and was significantly higher than the control but was not significantly different than POLYON which had 2.44 kg ha -1 cumulative N2O fluxes. The fairway control had 0.44 kg ha -1 and was not significantly than the POLYON treatment. On the rough UMAXX had significantly higher N2O fluxes than all other treatments totaling 2.78 kg ha -1; while the other fertilizer treatments on the rough were not significantly than each other and had cumulative averages of 1.47, 1.37 and 0.72 kg ha -1 for BCMU, POLYON and the control, respectively. The nursery greens and native site had cumulative N2O fluxes of 0.46 and 0.53 kg ha -1, respectively. Interestingly the fairway, rough, greens and native areas were all sources of CH4 emissions. There were no significant differences between the fairway and rough with annual cumulative emissions of 0.46 and 0.47 kg ha -1, respectively. The greens and the native areas had cumulative CH4 emissions of 0.51and 0.25 kg ha -1, respectively.