## 2 Materials and Methods  
In June 2019, the rootzone of a 'Penn G2' creeping bentgrass putting green maintained within the PSU Valentine Turfgrass Res. Center (University Park, PA, USA) was sampled to a 15-cm depth for routine soil fertility analysis by the PSU Agric. Anal. Services Laboratory. Maintenance of the putting green system in growing months included semi-monthly application of paclobutrazol plant growth regulator (Trimmit 2 SC, Syngenta Crop Protection, Greensboro, NC, USA) at label rates, irrigation to prevent wilt, and moving 6 \(\pm\) 1 days each week at a 3.1-mm height of cut. Clippings were collected and not returned. Following moving on 8 July, two separate randomized complete block designs, each comprised of sixteen (16) plots in four (4) blocks, were installed. All 1.83 \(\times\) 0.76 m (1.39 m\({}^{2}\)) plots were separated by a 0.61-m boundary on their short-side border. Following moving on 9 July, liquid \(N\)-fertilized treatments (Table 1) were applied to all plots in four blocks (Table 1) to supply 9.76 kg N/ha (0.2 lbs N per 1000 ft\({}^{2}\)). A CO\({}_{2}\)-powered backpack sprayer applied all treatments in 815 L ha\({}^{-1}\) carrier volume, per a 25-mesh nozzle strainer and even-spray tip (TeeJet\({}^{\oplus}\) 1108 EVS, Spraying Systems Co., Glendale Heights, IL, USA) equipped spray wand. An unfertilized control plot was treated in each block using de-ionized H\({}_{2}\)O. Each application of described foliar treatment to an experimental unit was immediately followed by installation of its dedicated ammonia-measuring closed flux-chamber [3, 23]. Three flux trapping-efficiency chambers were modified only by installation of a 3.1 mm hole on the opposite end of the intake tube and case fan and subsequently covered by electrical tape. A 15 mL HDPE beaker, filled with 5 mL of 0.156 M (NH\({}_{4}\))\({}_{2}\)SO\({}_{4}\), was then carefully placed to reside directly beneath the drill hole. Each flux trapping-efficiency chamber was then installed over the plot and beaker and driven to a 25 mm soil-penetration depth using a rubber mallet. Scrubbing flask preparation and tube connections were conducted as described previously. A hypodermic needle containing 2 mL of 10 M KOH was then inserted through the tape seal and hole, and its contents emptied into the beaker. Thus, trapping efficiency flux chambers were prepared in triplicate immediately following activation of the vacuum pump. Complete volatilization of N in the 0.156 M (NH\({}_{4}\))\({}_{2}\)SO\({}_{4}\) aliquot generated the equivalent of 9.76 kg/ha NH\({}_{3}\)-N within the chamber head space. The following day (10 July), gas scrubbing flask contents were collected from the plots in the order foliar treatments were applied 24 h earlier. The vacuum hose connecting the scrubbing flask to the manifold was clamped before unsealing and decanting the 2% H\({}_{3}\)BO\({}_{3}\) solution into labelled, 175 mL, wide-mouth HDPE bottles. The bottles were tightly-capped and boxed for transfer and subsequent titration by standardized 0.02 N HCl in the laboratory. Measurement of NH\({}_{3}\) emission was limited to the 24 h post-application period as it constitutes the interval between typical moving events and/or time golf course managers withhold irrigation following foliar applications.