Golf Course Superintendents manage creeping bentgrass greens using management strategies that will provide smooth, uniform, fast, healthy greens. This strategy often involves keeping bentgrass “lean” or spoon fed to minimize unwanted top-growth and succulence. Foliar or liquid feeding has become a standard spoon-feeding approach. Research, however on the benefits of liquid/foliar feeding on turf performance, health, disease, and soil nutrient dynamics is limited. Initial research at OSU has shown a positive relationship between foliar feeding and turf performance/disease incidence.
The purpose of this research project was several fold:
1) to evaluate and compare bentgrass performance under a base foliar versus a base granular seasonal program.
2) to evaluate bentgrass performance under a combination foliar and granular program.
3) to evaluate the performance of Grigg Brothers foliar and granular products against a foliar and granular standard.
Materials and Methods The study was conducted on an established ‘Penncross’ creeping bentgrass green with a USGA spec rootzone at The OTF Turfgrass Research and Education Center at The Ohio State University, Columbus, Ohio. The experimental design was a randomized complete block with three replications.
The fertilizer treatments are provided in Table 1.
Grigg fertilizers consist of two foliar fertilizers:
(1) Green Ultra (13-2-3 + Iron) containing 11% urea and 1.4% chelated iron plus other micros and (2) PK Plus (3-21-18 + micros) containing 2.1% urea and 0.4% chelated iron plus other micros; and Grigg granular fertilizers (1) 16-4-8 Turf Rally containing 11% urea and 3% iron plus other micros and (2) 7-7-7 Seven Iron containing 4.1% ammoniacal N and 7% with other micros. Bulldog (28-8-18) is a water soluble powder consisting of a 4.8% nitrate N and 22.2%
urea N with 0.2% chelated iron and other micros. UHS 18-8-18 is the granular standard.
The study was initiated June 8, 2005. The liquid materials were applied using a CO2 pressurized sprayer equipped with two flat fan nozzles calibrated to deliver two gallons per thousand square feet. The granular materials were applied using the shaker jar method. Mowing was performed three times per week using a Toro 1000 walk behind greens mower with a bench setting of 0.171 inches and clippings were removed. Plots were monitored for disease incidence, insect activity and weed encroachment. The site was irrigated as needed to prevent wilt and pesticide applications were made when disease and insect pressure exceeded acceptable threshold levels.
Turfgrass color/quality ratings were taken approximately every two weeks using a scale of 1 to 9 with 1 representing poorest, 6 representing just acceptable, and 9 representing best.
Results and Discussion
Creeping bentgrass color/quality as affected by fertility treatment is provided in Table 2. All fertilizer treatments/programs resulted in significantly higher bentgrass quality than the unfertilized bentgrass. Unfertilized bentgrass quality was well below unacceptable (i.e. < 6.0) on all rating dates.
The foliar treatment/programs (Grigg base and Bulldog) provided unacceptable bentgrass quality for the first several weeks following program initiation. Bentgrass quality increased progressively for the remainder of the season for both foliar source programs. Bentgrass quality responses were similar between the two latter foliar programs throughout the season.
The granular treatment/programs (Grigg Base and UHS) provided better initial green-up than the foliar treatments. Bentgrass quality increased progressively with both granular treatments throughout the season. Bentgrass quality responses were similar between the latter granular sources throughout the season, except for the more rapid initial green-up from the Grigg base
granular treatment.
Bentgrass quality was generally similar between the granular (Grigg Base and UHS) programs and foliar (Grigg Base and Bulldog) programs on most rating dates.
The Grigg Combo treatment provided the best overall bentgrass quality throughout the season. Initial and mid-season quality responses (i.e. June through August) were superior to all other treatment programs. Fall responses with Grigg combo were excellent but not significantly different from the other treatments.
