Topdressing To ProtectBentgrass Greens In Winter

An Iowa State study findsthat fall topdressing treatments

and nitrogen applicationsvisibly improve spring recovery

on two types of greens.

Nick ChristiansIowa State University

Kern DiesburgIowa State University

Jeff NusKansas State University

This is a view of two study areas covered in the following article shortly after treat-ment was applied. The modified soil is in the foreground, and the Nicollet soil isin the back. Darker plots have been treated with the 1:1:1 topdressing; light plotswith the 7:1:2 topdressing; and the green plots are controls that received notopdressing.

The green is the most expensive,highly maintained and delicate turfgrassarea on the golf course. In the centraland northern United States and throughmuch of Canada, winter is a particularlydifficult time to maintain golf coursegreens. These areas are susceptible toa variety of forms of winter damage,including cool temperature diseases,direct low temperature kill, desiccation,traffic and frost heaving. Extended

66

periods of ice cover also can damagegreens.

In the central plains of the UnitedStates and Canada, desiccation isresponsible for much of the winterdamage on greens. These regions oftenhave extended periods in the wintermonths with no snow cover and littlemoisture from rain. They also areknown for winter and spring winds thatdry the turf, causing extensive damage

from desiccation where winter irrigationis not possible.

Many techniques and materials havebeen used to protect golf course greensfrom winter desiccation, including theuse of protective blankets, polyethylenefilms, wood and synthetic fibers,branches and other debris, fences tohold snow cover and a soil topdressinglayer. Each technique has been used

Continued on p. 68

Golf Course Management I September 1987

with success, but each has its problems,including in some instances high

A high degree of managerialskill and knowledge isrequired for use of any

of these methods.

material costs - and, with polyethylenefilms and other synthetic materials, anincrease in cool temperature diseases.A high degree of managerial skill andknowledge is required for the use of anyof these methods.

The use of other cultural practiceswith winter protection techniques hasnot been fully investigated. For exam-ple, the use of dormant fertilizer appli-cations may be useful with some of thetechniques, although this practicewould not be recommended with poly-ethylene films and other methods thatresult in temperature increases and latewinter growth.

Iowa State ExperimentIn a four-year study at Iowa State

University, combinations of nitrogenfertilizer and two types of soil topdress-ing were applied to Penncross creepingbentgrass greens that had been estab-lished on both a native Iowa soil and asoil modified with peat and sand. Theobjective was to observe the effects offall topdressing and late-fall nitrogen

TOPDRESSING from p. 66

applications on the spring recovery ofthese two types of greens.

Two adjacent experimental greensthat had been established with Penn-cross in September 1979 were used inthe study. One area was formed of aNicollet soil with a pH of 6.5. Thesecond green was composed of a"modified" soil that had been con-structed of one part sand, one partNicollet soil and one part peat. The pHwas 7.9. Physical tests performed onthis soil before the initiation of treat-ments showed that this soil contained4.6 percent gravel, 62.3 percent sand,21.3 percent silt and 11.8 percent clay.The bentgrass was maintained at a1/4-inch mowing height. The area wasfertilized during the season with liquidurea solutions at a rate of 0.2 lb.Nl1,000 square feet whenever thebentgrass showed signs of nitrogen defi-ciency. Insecticides and fungicides wereused as needed during the season.

Three main treatments were includedin the study. The first was a controlwhere no topdressing was applied; thesecond consisted of a 7: 1: 2(sand:soil:peat mixed on a volumebasis) topdressing applied at 0.77 cu.yd./1,000 square feet (0.23 inchdepth) to the surface of the green; andthe third included a 1: 1: 1(sand:soil:peat) applied at the same ratein the same way.

Each topdressing plot measured 10feet by 10 feet. The topdressing plotswere further divided into three nitrogentreatments that included.a control, 0.5,and lib. Nl1,000 square feet appliedin the form of gran ular urea.

Fertilizer treatments were appliedafter top growth had ceased, betweenNov. 10 and Nov. 18 in 1980, 1981,1982 and 1983. Topdressing treat-ments were applied immediately afterthe fertilizer was applied. The areasreceived no supplementary irrigationduring the winter and early spring. Eachof the treatments was repeated threetimes on each of the two greens.

Data collection began each year inthe spring with the first sign of greencolor in any of the plot areas and con-tinued until all plots showed completerecovery from winter dormancy. Thedata collected was designated springrecovery, which was based on color,density and uniformity (the lack ofwinter damage), and rated on a scaleof 1 to 9, with 1 equaling no sign ofrecovery and 9 equaling total recovery.

Varying Weather ConditionsWeather conditions during the four

winters of the study varied greatly. The1980-81 winter was mild, with very little

The 1981-82 season wasthe opposite extreme,

with very cold temperaturesand heavy snow cover.

snowfall or snow cover and monthlymean maximum temperatures thatranged above freezing. The 1981-82season was the opposite extreme, withvery cold temperatures and heavy snowcover. The 1982-83 winter began mild

Continued on p. 70

68

The effects of topdressing treatments and fertilizer treat-ments on spring recovery of Penncross creeping bentgrass.

Monthly mean temperatures, snowfall and snow cover on thestudy area for 1980-84(0 degree centigrade; equals freezlrlg,and 2.54 em equals 1 inch).;

Golf Course Management / September 1987

Spring recovery of Penncross creeping bentgrass greens with and withouttopdressing in Apri/1981. Plots showing no recovery are untreated controls.

The effects of topdressingwere greatest following

the mild winters of1980-81 and 1982-83.

C!ndended with heavy snow, whereasthe 1983-84 season began with verycold temperatures and heavy snow butended with rather mild temperaturesand a period in February with no snowcover.

Topdressing treatments improvedspring recovery in each of the testingyears. However, the first date of visiblegreen-up and the amount of time fromfirst green-up to the time when no

Bibliography1. BEARD, J.B. (1964a) Effectsof ice, snow and water

covers on Kentucky bluegrass,annual bluegrassandcreeping bentgrass. Crop Sci. 4:638.

2. BEARD, J.B. (1964b) Causal agents in winter inju-ry of turfgrassand their relative importance. Agron.Abstr. p. 99.

3. BEARD, J.B. (1966) Direct low temperature injuryof nineteen turfgrasses.Mich. Agric. Exp. Stn. Bull.48(3):377.

4. BEARD, J.B. (1969) Covers for the protection ofturfgrassesagainst winter desiccation and low tem-perature injury. Agron. Abstr. p. 52.

5. BEARD, J.B. (1973) Turfgrass: science and culture.Prentice-Hall, Englewood Cliffs, NJ.

6. BEARD, J.B. (1982) Turf Management for GolfCourses. Burgess, Minneapolis, MN. pp. 452-458.

7. LEDEBOER, F.B. and SKOGLEY, C.R. (1967)Plastic screens for winter protection. Golf Superin-tendent. 35(8) :22-23.

8. WATSON, J.R., KROLL, H., and WICKLUND, L.(1960) Protecting golf greensagainstwinter kill. GolfCourse Rep. 28: 10-16.

9. WATSON, JR., and WICKLUND, L. (1962) Plas-tic covers protect greens from winter damage. GolfCourse Rep. 30:30-38.

10. WATSON, J.R. (1964) Methods of minimizingwinter damage. Agron. Abstr. p. 103.

11. WATSON, J.R. (1968) Blankets to protect gol1greens against winter injury. Agron Abstr. p. 61.

12. WATSON, J.R. (1968) Prevention and control ofdesiccation on golf greens. In: Proc. of the First Int.Turfgrass Res. Con/., Sports Turf Res. Inst., Bin-gley, England, pp. 301-305.

Although topdressing and fertilizationtreatments did not increase cool-temperature disease infestations on thisarea and likely would not on most openareas in the Midwest, caution should beused with these treatments without theuse of fungicides in more protectedareas or in areas where there has beena history of cool-temperature diseases.

The extent to which topdressingtreatments can improve spring recoverywill likely be surprising. If the methodis being used for the first time, a smalluntreated area should be retained sothat the real effects can be observed.

The visible effects of topdressing wereapparent each year, but particularly inyears following mild winters. The visi-ble effects of fertilization were moresubtle .. The application of topdressing to

bentgrass greens at a rate of 0.77 cu.yd./l,OOO square feet after growth hasceased in the fall may have a beneficialeffect on spring recovery, particularlyduring mild winters with little snowfall,regardless of whether the topdressinghas a high sand content. Spring recov-ery can be further enhanced by the ap-plication of nitrogen fertilizer at rates upto 1 lb. N/l,OOO square feet to thegreen's surface before topdressing ap-plication.

The effects of topdressing weregreatest following the open, mildwinters of 1980-81 and 1982-83. Theleast benefit from these treatments wasobserved after the extended snow coverand cold temperatures of 1981-82.

Neither topdressing material was con-sistently better than the other on eithersoil type, although there was a slight ad-vantage to the 1: 1: 1 topdressing in thesprings of 1983 and 1984 on the modi-fied soil and the springs of 1981 and1984 on the Nicollet soil. The ratingsfor the 7: 1:2 topdressing exceededthose of the 1: 1: 1 only in the spring of1982 on the Nicollet soil. It had beenexpected that the darker-colored 1: 1: 1topdressing would be consistently su-perior to the 7: 1:2, but this was not thecase.Effects Of Fertilization

There was an increase in springrecovery with increasing fertilizer rateson both soils in each year, with the ex-ception of spring 1982. At no time didthe application of urea have a detrimen-tal effect on the bentgrass. Even whenlate-season snow covered plots that hadbegun to recover in 1982, 1983 and1984, no signs of cool-temperature dis-eases were observed on any of thetreated areas, even though no winterfungicide applications were made afterthe 1981 season.

the greater moisture- and nutrient-holding capacity of the Nicollet soil. Theearliest date of spring green-up and theduration of treatment differences didnot vary between the two soils,however.

from p. 68TOPDRESSING

differences could be observed amongtreatments varied with the year. Inspring 1981, treatment differences wereobserved for 31 days, followed by 22days in spring 1982, 51 days in spring1983 and 15 days in spring 1984. Thevery short duration in 1982 can beattributed to the extended snow coverinto April. The extended period of 1983was due to the lack of snow cover andwarm temperatures in February fol-lowed by heavy snows in March andApril.

The spring recovery ratings for thecreeping bentgrass on the Nicollet soilwere generally higher than for equiva-lent treatments on the modified soil.These higher ratings are likely due to

70 Calf Course Management I September 1987