Evaluation of Cytokinian-Plant Extract, Iron, and Nitrogen Products On Creeping Bentgrass Putting Green Quality.

Summer quality of creeping bentgrass (Agrostis stolonifera L) research greens in Lemont, IL and College Park, MD was monitored in response to six liquid fertilizer and plant extract products in 2008.  Treatments included Knife 12-0-0, Lesco’s 12-0-0 Plus Micronutrients, Ultraplex 5-0-3, IronRoots 0-2-4, PanaSea Plus 0-2-2, and Roots Concentrate 0-0-0.  All treatments were applied at label rates. Treatments were applied every 14 days from Jun to Sep.  Standards for comparison were an untreated control and urea at 7.4 kg N ha^-1.  Products that did not contain N were applied with and without N from urea.  Turf was an ‘L-93 plus Penn G-2’ blend in IL and ‘Providence’ in MD and treatments were arranged in a randomized complete block with four replications.  Color and quality were assessed visually.  Normalized difference vegetation index (NDVI) also was used to assess color/chlorophyll levels.  Treatments containing N from urea generally provided best visual quality and higher NDVI color measurements over the entire season at both locations.  Urea also limited scalping injury in MD.  Products containing chelated Fe darkened the foliar color and enhanced quality, but the observed effect was transient and lasted 7 to 14 days.  Plant extract products without Fe (i.e., Roots Concentrate and PanaSea Plus) improved quality at times, but the level attained was often not acceptable for golf greens during summer.  Overall, the visual quality benefits accorded by all products tested were generally negligible when without N from urea because they were unable to attain consistent acceptable levels (≥ 7.0; 0-10 scale) necessary for golf greens.  Applied alone, urea was the most economical treatment in the study.  Future field research should investigate products containing plant extract and/or Fe for effects on rooting and drought avoidance.