The crazy spring weather [in Nebraska] has made reestablishing turf difficult following this year’s winterkill. Spring started out cold and dry and then, as if someone flipped a switch, it’s been hot, humid, and very wet. It created a very difficult environment to establish new grass. As a result, there are still many thin and open areas on Nebraska greens, tees, and fairways.
On a recent golf course visit, a very competent superintendent asked what he should do to get those areas to thicken up. He already seeded three times, had been aerating, and lightly fertilizing. He was proactive and started down the road to recovery early in the spring. Was another round of seeding required? He had done a good job getting bentgrass established and there were strong stolons creeping toward open areas. After some discussion, we decided the appropriate action was to increase nitrogen fertilization rate because seeding in July can be problematic and there were young bentgrass plants spread throughout the thin areas. He said, “It’s time to feed the beast.”
It’s certainly been a frustrating spring and everyone’s level of winterkill recovery is slightly different. However, one of the most consistent themes over the past month has been too little nitrogen fertilization on thin areas. All the turf texts describe the perils of excessive mid-summer fertilization. However, nitrogen requirements for young thin turf are much higher than those of an old established stand. One of the main reasons we fertilize turf is to replace nutrients lost during clipping removal, and we’ve become familiar with the amount of nitrogen required to sustain turf quality during normal maintenance. This year is unique because we need to apply enough nutrients to regrow all the green tissue that was killed last winter in addition to resupply nutrients removed during mowing. The near record precipitation this month also affects nitrogen requirements because it increased the potential to leach nitrogen and promote denitrification in hot and saturated soils.
As we enter July, consider holding off seeding and fertilizer damaged areas with soluble forms of nitrogen fertilizer. Application of a medium to slow release product will also help boost soil fertility levels, especially on poor soils with low soil fertility. New research at the John Seaton Anderson Turf Research Center looks at the potential for organic fertilizers to help improve these poor and infertile soils. Routine application of organic fertilizers may be the way to increase turf productivity on these poor soils. Finally, aerate weak areas during cool periods to improve soil aeration and promote recovery, and avoid vertical mowing areas where stolons are creeping into thin spots.
The winterkilled turf at the JSA Turf Research Center is nearly gone. We were fortunate because we got seed in the ground at the ideal time in March, have had a strong fertility program, and the luxury of no golfer traffic. Come to our Turfgrass Field Day on July 23, 2014 to see our winterkill recovery trial, nitrogen fertilizer work, and a new research green we established with ‘V8’, ‘Penn A1’, and ‘Penncross’ creeping bentgrass and even ‘Champion’ ultradwarf Bermudagrass and fine fescue. Find more information about Summer Field Day here: Registration and Attendee Brochure.
Bill Kreuser, Assistant Professor and Turfgrass Extension Specialist, wkreuser2@unl.edu
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