Integration of Iron Into N Fertility Regimes for Regulation of Fertilizer and Water Requirements of Penn A-Series Creeping Bentgrasses (Agrostis stolonifera L.).

Field experiments were conducted from May to Oct. 2008 to investigate the effects of combined N and iron treatments on fertilizer and water requirements of ‘Penn A-1/A-4’ creeping bentgrass (Agrostis stolonifera L.), managed as putting greens. Either sand- or soil-based putting greens were treated with combinations of three NH₄NO₃ rates (15, 30, or 45 kg N ha^-1 mo^-1) and three FeSO₄ ·7H₂O rates (2.5, 5, or 7.5 kg Fe ha^-1 mo^-1). Irrigation was largely suspended after June 20 and practiced only to prevent severe dehydration. Soil moisture and temperature were monitored daily. Turfgrass color, canopy density, clipping yield (CY), leaf water content (LWC), tissue nutrient levels, ball roll distance (BRD), root length density, and root mass were measured to evaluate growth and visual quality. Clipping yield and LWC was reduced by drought stress, regardless of soil types. Leaf water content generally increased with increasing N rate, regardless of soil moisture levels. Ball roll distance was found negatively correlated with N rate. Nitrogen rate was the most decisive factor for CY, LWC, and BRD, while iron rate for greener color, regardless of soil types or moisture levels. Our data suggest integration of iron into N fertility regimes may promote visual quality and drought resistance of Penn A-series creeping bentgrasses.