EFFECT OF N-FORM ON GROWTH AND NUTRIENT CONTENT OF CREEPING BENTGRASS

The primary nitrogen forms utilized by plants are ammonium and nitrate. Although the importance of nutrients other than nitrogen for proper turfgrass growth is well established, the amounts of these nutrients in the plant tissue in relation to the use of different N-forms has not been clearly documented. This study was conducted under greenhouse conditions to determine the effect of N-form and cutting regime on growth, macronutrient, and micronutrient content of creeping bentgrass (Agrostis palustris Huds. 'Penncross'). Treatments consisted of 100% NO3- (calcium nitrate), 100% NH4+ (ammonium sulfate), and a 50:50 ratio of NH4+:NO3-. Half the turfgrass plants were maintained at a height of 1 cm (cut), while the other half of the plants were not cut until the end of the study (uncut). The uncut 50:50 treatment yielded the highest shoot, verdure, and total plant dry matter, while the uncut NO3- treatment produced the highest root dry matter. The uncut NH4+ treatment yielded the least shoot, root, and total plant dry matter. Plants of the uncut NO3- treatment had greater accumulation of macronutrients in the shoot and root tissue compared to plants of the NH4+ treatment. The uncut NO3- and 50:50 treatments had higher total accumulation of micronutrients compared to the uncut NH4+-treated plants. The cut NO3-treatment resulted in the highest macronutrient and micronutrient contents in the root tissue in comparison to other cut treatments. The cut treatments had the highest percentage accumulation of nutrients in the verdure tissue, while the uncut treatments had the highest percentage accumulation of nutrients in the shoot tissue.