Nitrogen uptake and leaching potential of polymer coated nitrogen fertilizers in a turfgrass environment

Establishing and maintaining quality turfgrass requires nitrogen (N) fertilization. However, potential leaching losses of N present environmental and economic concerns. Nitrogen losses deprive turfgrass of an essential nutrient and serve as a potential pollutant to surface and ground waters. Studies were conducted to investigate the effect of polymer-coated (NH{dollar}rm sb4)sb2SOsb4{dollar} (AS), urea, and KNO{dollar}sb3{dollar}, with varied coating thicknesses and sizes, on uptake and leaching of applied N to bermudagrass (Cynodon dactylon) grown on sandy soil and the factors effecting the N release.; A laboratory study was conducted to investigate the effect of temperature, coating thickness, and N substrate on the release of N from the encapsulated fertilizers into deionized H{dollar}sb2{dollar}O. An increase in temperature from 25{dollar}spcirc{dollar}C to 35{dollar}spcirc{dollar}C increased N released from 30% to 56% for coated AS with 4.7% coating (CAS-4.7), and from 70% to 78% for coated urea with 4.8% coating (CUrea-4.8). Data suggest a differential increase in solubility of the N substrates. Increases in coating thickness reduced N release differently, depending on N substrate and granule size.; In a field study, using open-ended lysimeters equipped with multi-depth samplers, the N uptake and leaching of uncoated and polymer-coated {dollar}sp{lcub}15{rcub}{dollar}N AS and urea applied to bermudagrass growing on sandy soil were determined. Nitrogen uptake recovery using an {dollar}sp{lcub}15{rcub}{dollar}N tracer method and a difference method increased as a result of coating, except for CAS-9.8. Coated Urea-10 produced the highest N uptake, followed by CUrea-4.8 and CAS-4.7 Nitrate-N concentrations in the intermediate vadose zone (IVZ) at the 30 cm depth, and the saturated zone at 90 and 120 cm, were affected by applied N, coating and coating thickness.; In another lysimeter study, the N sources were applied to lysimeters packed with a sand-based golf green profile. Nitrogen uptake and N leached to the 46 cm depth were determined. Nitrogen uptake ranged from 26% (KNO{dollar}sb3{dollar}) to 69% (CAS-7.5). Nitrogen leached from the CAS and CUrea treatments ranged from 0.3% (CAS-15) to 7.7% (CAS-7.5) of applied N.; This study documents the effectiveness of the polymercoated N sources in minimizing N leaching and increasing N uptake in a turfgrass environment.