SportsTurf provides current, practical and technical content on issues relevant to sports turf managers, including facilities managers. Most readers are athletic field managers from the professional level through parks and recreation, universities.
Issue link: http://read.dmtmag.com/i/448298
Field Science 12 SportsTurf | February 2015 www.sportsturfonline.com T he basic concept of weed con- trol in turfgrass ecosystems will really never change. The paramount principle against the establishment of weeds in any turfgrass system is the culture and main- tenance of a healthy, dense, competitive stand of turf. A preventative cultural approach is successful only on sports fields if proper fertilization, mowing, irrigation, pest control, core cultivation, overseeding, etc. practices are imple- mented in an integrated management program. Unfortunately, on sports fields an additional challenge to maintaining a dense stand of turfgrass is foot traffic (in many cases severe) that creates the additional stress of both direct physi- cal wear and tearing/shearing/divoting that weakens the turfgrass and opens up the surface to an increasing oppor- tunity for weed encroachment and for the germination of annual grassy weeds. Basically, annual grassy weed control in any turfgrass system is what I refer to as the "science of voidology" and "eco- logical niches." Weed seed present in the soil is lying dormant just waiting for an opportunity under the right environ- mental and cultural conditions to invade a weakened turf with open voids. Annual grassy weeds like crabgrass prefer these voidology and ecological niche condi- tions. Weed encroachment on sports fields is much more likely due to "voidol- ogy conditions" and more so than any other turfgrass management system. Sports turf managers therefore require the ultimate expertise in the art and science of turf management as the odds in many cases are against you. Although there are many potential problematic weeds that can invade athletic fields certainly the most common annual grassy weed across the country is crabgrass as it observes no boundaries. It is a C4 turfgrass in the same physiological class as the warm-season grasses and thus thrives under moist and warm/hot environmental conditions (ecological niche). Give crab- grass an opening/opportunity under the appropriate conditions and it germinates and infests turf quickly with tillering occurring within weeks of germination. The Preemergence/ herbicide dilemma ■ By Dr. John r. Street, Pamela J. Sherratt, anD Dr. DaviD S. GarDner Crabgrass infestation on a sports field. Table 1. Soil temperatures for annual grass germination.