Nitrate and Ammonium Nitrogen Effects on Growth of Creeping Bentgrass and Annual Bluegrass

Abstract

Five cultivars of creeping bentgrass ( Agrostis palustris Huds. ‘Emerald’, ‘Penncross’, ‘Penneagle’, ‘Prominent’, and ‘Seaside’) and annual bluegrass ( Poa annua L.), a weed, were grown in pot culture in silica sand and supplied with nutrient solutions in which 0%, 25%, 50%, 75%, or 100% of the N (210 mg·liter −1 ) was and the remainder was . Growth rate, as measured by new leaves and tillers, and final size, as measured by leaf width, leaf number, tiller number, and cover, were significantly different among species and cultivars and among N ratios. All species/cultivars produced their best growth with some mixture of and . Annual bluegrass grew better in high- conditions, while the bentgrass cultivars grew as well or better in high conditions. There were significant differences among the bentgrass cultivars in their sensitivity to N source, with ‘Penncross’ being the most sensitive and ‘Seaside’ the least.