Foliar and Root Urea-Nitrogen Fertility of Five Warm Season Turfgrasses Under Salinity Stress.

Salinity stress is a widespread turfgrass management problem in coastal areas and environments where water use restrictions are common.  However, little is known about salinity stress and how it affects foliar and root fertilization of turfgrasses.   A two-year study was conducted in the greenhouse facilities at Clemson University from July-October of 2009-2010.  The objective was to evaluate three ultradwarf bermudagrasses  (Cynodon dactylon (L.) Pers. X C. transvaalensis Burtt-Davy) ‘Champion’, ‘Mini-Verde’, ‘Tif-Eagle’, ‘Seadwarf’ seashore paspalum (Paspalum vaginatum Swartz.), and ‘Diamond’ zoysiagrass (Zoysia matrella (L.) Merr.) under salinity stress and two nitrogen fertility regimes.  Foliar and root applications of urea-N at 9.76 kg ha^-1 were applied weekly for 12 weeks.  Two irrigation levels (0 and 8,000 ppm NaCl) were applied every 48 hours to replenish ET losses.  Parameters measured included: turf quality, tissue nutrient content, proline accumulation, and electrolyte leakage.  Saline irrigation significantly reduced N, P, and K concentrations in leaf tissue at the conclusion of both years.  Under salinity stress, ‘Seadwarf” seashore paspalum exhibited significantly higher N, P, and Na concentrations in leaf tissue under foliar applications of urea.  Tissue K concentrations in ‘Champion’ were reduced in the greatest amount by saline irrigation at 6 and 12 weeks in both years of the study.  At  the conclusion of the study, all turfgrasses accumulated significantly higher levels of proline under salinity stress with ‘Champion’ displaying the greatest increase in proline accumulation from > 1 μg /g FW under fresh water irrigation to over 9 μg /g FW under salinity stress.