Root responses of bermudagrass to mowing height and frequency

Abstract

Bermudagrass (Cynodon sp.) is used extensively throughout the South on golf courses, sports fields, home and commercial lawns, and utility areas. Turf managers are routinely advised to raise mowing heights to improve the root system of the turf. 'This advice is based largely on studies conducted on cool-season turfgrasses such as Kentucky bluegrass (Poa pratensis L.), tall fescue (Festuca elatior var. arundinacea [Schreb.] Wimm.), and bentgrasses (Agrostis spp.), and on grazing studies of forage grasses. There is a need to document the effects of mowing height and frequency on the root system and carbohydrate storage of warm-season turfgrasses such as bermudagrass. Turfgrass plugs of 10 cm diameter were transplanted into polyvinyl chloride tubes of similar diameter and 120 cm tall, and composed of four 30 cm sections stacked end to end. The upper three sections were filled with washed sand and the bottom was filled with pea gravel to provide drainage. This design permitted the three upper sections of root zone to be studied separately. Common bermudagrass (Cynodon dactylon [L.] Pers.) was used in a mowing height by frequency study, with mowing height treatments of 2.5 and 5.1 cm, and mowing frequencies of 2, 7, and 14 days. Tifgreen bermudagrass (C. dactylon x c. transvaalensis Burtt Davy) and common bermudagrass were used in a mowing height study, with mowing height treatments of 0.6, 1.3, 2.5, and 5.1 cm, all mowed at 2 day intervals. Mowing frequency had little effect on common bermudagrass, except that a greater shoot mass was produced by a 2 day than a 14 day mowing interval. Tifgreen bermudagrass produced more root volume, mass, and length density, as well as dry shoot mass than common bermudagrass. Mowing height had major impacts on root and shoot growth and carbohydrate storage. Generally, the turfs were adversely affected as mowing height decreased. Mowing height had to be raised above 1.3 cm to increase overall rooting and above 2.5 cm to increase rooting at depths below 30 cm.