EFFECTS OF MOWING HEIGHT AND NITROGEN ON A TURF TALL FESCUE IN COMPARISON TO PERENNIAL RYEGRASS ANDBROWNTOP BENT SOWN ALONE OR IN MIXTURES. 2. WINTER WEAR

摘要

An experiment was conducted to compare the winter wear performance of six grass mixturesunder two mowing heights (18, 50 mm) and at three nitrogen (N) rates (15, 30 and 45 g N nr2year~(-1)) at Palmerston North on a brown sandy loam. The turfgrasses were 'Grasslands Garland'tall fescue (Festuca arundinacea), 'Grasslands Trophy' perennial ryegrass (Lolium perenne)and 'Grasslands Egmont' browntop bent (Agrostis capillaris syn. A. tennis] sown alone or inbinary mixtures. Continued small weekly applications of wear (3 passes) over winter resulted in more accumulated turf damage than 10 passes applied every 4 weeks. Wear tolerance, as determined byrelative changes in ground cover of sown species, was (in decreasing order) tall fescue, ryegrass,and browntop, while the level of damage to the turf was greatest in browntop and ryegrass, andleast in tall fescue. However, due to establishment differences, overall live grass cover waslower for tall fescue. Of the mixtures, ryegrass/browntop had enhanced cover of sown grassesand less damage compared with each of these species sown alone. Other binary mixtures tendedto have characteristics that were intermediate of the two species when sown alone. Increasednitrogen reduced the effects of wear more than did a greater mowing height. Browntop was theleast responsive species to mowing height. Where nitrogen is a limiting factor on winter sportsturf such as rugby fields, these mixtures should be mown at 50 mm to increase their wear toler-ance to damage. A nitrogen rate of 30 g N m~(-2) year~(-1) was optimum for improving the performance of mixtures, with generally no significant improvement at the 45 g N rate. Ryegrass was the most responsive grass species to N, browntop intermediate, while tall fescue had little positive or negative responses. It is postulated that the shallow rooting Poa annua, present in tall fescue plots at 7times the amount that occurred in any of the other grass mixtures, responded to the increased Nrather than the tall fescue. While tall fescue demonstrated advantages in terms of wear tolerance, its slow establishment and high weed content will require extra management inputs to minimise these short comings and may limit its use in New Zealand to inclusion in mixtures with other grasses in appropriatesituations.