FERTILITY
Figure 3
ber 7 in the northeast , shows two major problems . The first is that the fertilizer was not removed from an impervious surface and will be easily transported off site and lost ( and likely lead to surface water pollution ). The second problem is that the fertilizer applied is a methylene urea source . These require summer-like conditions to release the nutrient .
Cool- and warm-season turf adjustments
Cool-season turf With cool-season turfs such as Kentucky bluegrass , perennial ryegrass and tall fescue , good timing signals from Mother Nature are when the heat of the summer is over , yet while nutrients are still likely to be absorbed . As such , early fall and late fall are good timing targets . Early fall applications stimulate both foliar growth and root growth , but less foliar growth than an equal amount of applied product would encourage in spring . Photosynthate produced in late fall are not abundantly translocated to shoots , but
instead move to stolons , rhizomes and roots in large part , helping the plants gain winter hardiness and earlier spring green-up .
In general , late-season programs do not eliminate the need for spring / summer fertilization , but allow the sports field manager the opportunity to use lighter rates that result in uniform shoot and root growth . The rate is also a key element in success of fall fertilization . In early fall applications , rates of 0.5 to 0.75 pounds N / 1,000 sq . ft . encourage recovery and overall turfgrass health , while light rates in the 0.2 to 0.3 pound N / 1,000 sq . ft . range are best in late fall when uptake is lower . In early fall , adequate time , temperature and moisture exists to encourage breakdown and utilization of the nutrients slowly and steadily , as opposed to late fall , when the goal is to get the nutrients into the plants fast and reap the benefits quickly .
If applications of K are needed , fall may not be the best time to deploy the nutrient in cool-season grasses . Potassium fertilization may
QUICK GUIDE : TIMING
When to :
• Fertilize when turf is actively growing .
• Fertilize when turf is establishing – seed , sod , sprigs , plugs .
• Fertilize to assist with turf recovery after stress periods and heavy traffic .
When not to :
• Avoid fertilization when turf is surging due to microbial nutrient release .
• Avoid fertilization on the “ shoulders ” of the growing season – as the turf is going into dormancy and before the onset of growth .
• Avoid fertilization when turf root growth has stopped due to ultra-high temperatures – nutrient apps during this time may burn heat-compromised roots .
increase snow mold severity , so K should be provided earlier in the season , which has the added benefit of potentially reducing anthracnose severity .
Often , summer is the offseason for cool-season turfs . When that is the case , lighter applications ( 0.5 pound of N per 1,000 sq . ft . per summer ) of controlled-release sources are preferred to avoid overstimulating the turf and to reduce the risk of diseases . When managing summer-active athletic complexes ( baseball , softball , soccer , etc .), 1 pound N per 1,000 sq . ft . of a controlled-release source applied
14 SportsField Management | January 2022 sportsfieldmanagementonline . com