THE INFLUENCE OF WEAR AND NITROGEN ON CREEPING BENTGRASS GROWTH

Abstract

The effects of nitrogen and wear stress on the growth of Penncross creeping bent-grass (Agrostis palustris Huds.) maintained as a putting green was evaluated from June 1978 to November 1979. The 8-yr-old sward was grown on a Fox sandy loam, mowed five times weekly and irrigated as required. Nitrogen was applied as ammonium nitrate at 1.5, 3.0 and 6 kg N∙100 m−2. Wear treatments, applied for specific periods of time, were zero, three and six passes per day. Turf injury was due to direct wear stress rather than soil compaction as the soil bulk density was unaltered by wear treatment. As wear treatments increased, thatch thickness, clipping yields and healing potential decreased. Electrical resistance measurements of leaf tissue decreased as wear stress increased. This technique provided a rapid and reliable estimate of leaf injury from wear stress. Nitrogen at 3 kg∙100 m−2 increased healing potential, turf greenness and root production over the zero N treatment. However, 6 kg N∙100∙m−2 was excessive. Despite the significant increase in green color, there was no significant increase in healing potential and root growth over the 3-kg rate and the annual bluegrass content of the turf was increased.Key words: Annual bluegrass, thatch, healing potential