NOVEMBER 1968 USGA GREEN SECTION RECORD A Publication on Turf Management by the United States Golf Association USCA GREEN SECTION RECORD A Publication on Turf Management by the United States Golf Association © 1968 by United States Golf Association. Permission to reproduce articles or material in the USGA GREEN SECTION RECORD is granted to publishers of newspapers and periodicals (unless specifically noted otherwise), provided credit is given the USGA and copyright protection is afforded. To reprint material in other media, written permission must be obtained from the USGA. In any case, neither arti­ cles nor other material may be copied or used for any advertising, promotion or commercial purposes. VOL. 6, No. 4 NOVEMBER 1968 Reorganization Moves Green Section Ahead .................................................... 1 Sources of Water by James B. Moncrief ................................................................. 4 The Fate of Herbicides by A. Robert Mazur............................................................ 8 Low Temperatures and Poa Annua by Dr. James B. Beard ............................... 10 Bermudagrasses in the Transition Zone by Dr. Elwyn E. Deal ....................... 12 Turf Twisters............................................................................................ Back Cover Published six times a year in January, March, May, July, September and November by the UNITED STATES GOLF ASSOCIATION, 40 EAST 38th ST., NEW YORK, N. Y. 10016. Subscription: $2 a year. Single copies: 35^. Subscriptions and address changes should be sent to the above address. Articles, photographs, and correspondence relevant to published material should be addressed to: United States Golf Association Green Section, P.O. Box 567, Garden Grove, Calif. 92642. Second class postage paid at New York, N. Y. Office of Publication: 40 East 38th Street, New York, N. Y. 10016 Editor: William H. Bengeyfield Managing Editor; Robert Sommers THE GREEN SECTION OF THE UNITED STATES GOLF ASSOCIATION Green Section Committee Chairman: Henry H. Russell, P.O. Box 697, Miami, Fla. 33157 Green Section Agronomists and Offices EASTERN REGION Eastern Office: P.O. Box 1237 Highland Park, N.J. 08904 Alexander M. Radko, Director, Eastern Region and National Research Director A. Robert Mazur, Eastern Agronomist James W. Timmerman, Eastern Agronomist SOUTHERN REGION Southern Office: P.O. Box 4213, Campus Station, Athens, Ga. 30601 James B. Moncrief, Director, Southern Region Holman M. Griffin, Southern Agronomist MID-CONTINENT REGION Mid-Continent Office: Room 905, 211 East Chicago Avenue, Chicago, III. 60611 James L. Holmes, Director, Mid-Continent Region F. Lee Record, Mid-Continent Agronomist WESTERN REGION Western Office: P.O. Box 567 Garden Grove, Calif. 92642 William H. Bengeyfield, Director, Western Region and Publications Editor G. Duane Orullian, Western Agronomist COVER PHOTO: Since 1951, the Green Section Visiting Service Program has been concerned with direct visits to USGA mem­ ber clubs. One of the first clubs to subscribe to this service was Recreation Park Golf Club, Long Beach, Calif., and here B. K. Jones and Ivan Rousey, staff members at the course, participate in a visit by their Green Section repre­ sentative. Reorganization Moves Green Section Ahead Evolution is as important to an organization as it is to an organism. Change and prog­ ress are synonymous with growth. Next year the Green Section will once again evolve and will have a new look. After completing a survey of its Member Clubs, the Green Section Committee and the USGA Executive Committee decided to set new dimensions for the Green Section. Henry H. Russell, USGA Green Section Committee Chairman put it this way: “Reorganization is an absolute necessity if the Green Section is to keep pace with the growth of golf in this country and the increase in USGA membership. Re­ organization will improve the Green Section’s efficiency, will provide better service to subscribers to our Visiting Serv­ ice, and because of the increased staff, will enable the Green Section to add new subscribers. There will be an in­ crease in its total volume of work.” To serve subscribers better, some Regional Offices have been relocated and new staff members added. The intention was to place each office close to the numerical center of each region’s Visiting Service subscribers. In addition, the work load for staff members has been better distributed, and subscribers will receive even better service in the years ahead. Mid-Continent Region The Green Section Mid-Continent office will now be located at 211 East Chicago Avenue, Chicago, III. James L. Holmes is Mid-Continent Director. He will team with F. Lee Record, Mid­ Continent Agronomist, and together they will visit subscribers in North Dakota, South Dakota, Nebraska, Kansas, Ohio, West Vir­ ginia, Kentucky, Indiana, Illinois, Wisconsin, Michigan, Minnesota, Iowa and Missouri. Southern Region A new regional office for the Green Section has been established in Athens, Ga. The new Southern Director is James B. Moncrief, who has been with the Green Section for over 13 years. The address is Box 4213, Campus Sta­ tion, Athens, Ga. 30601. His associate is Holman M. Griffin, Southern Agronomist. They will cover Visiting Service subscribers in Arkansas, East Texas, Louisiana, Mississippi, Florida, Alabama, Georgia, South Carolina, North Carolina, Tennessee, Virginia, and Maryland. Eastern Region Alexander M. Radko continues as the East­ ern Regional Director, and now assumes the additional duties of National Research Direc­ tor. He will be assisted by Robert Mazur and James W. Timmerman, Eastern Agronomists. They may be reached at Box 1 237, Highland Park, N.J. 08904. Their territory covers Maine, Vermont, New Hampshire, Rhode Island, Massachusetts, Connecticut, New York, New Jersey, Pennsylvania and Delaware. Western Region The largest territory of the Green Section (if you include the Pacific Ocean) lies in the Western Region. William H. Bengeyfield is the Regional Director and has recently become the Green Section Publications Editor. His co­ worker is Duane Orullian, Western Agrono­ mist. Together they will serve member clubs from the Rocky Mountain states west to Hawaii. Their office is Box 567, Garden Grove, Calif. 92642. New Emphasis on Research With the reorganization of the Green Sec­ tion, it is the USGA’s intention immediately to increase its support of turfgrass research activ­ ities. Al Radko will head this important pro­ gram. It is recognized that substantial support for specific projects is needed, and we intend to fill that need. Indeed, research has always been at the foundation of Green Section work. That base will now be strengthened, improved and revitalized. Maintaining the status-quo, is not good enough for today. It is time to move on to new information, to develop new con­ cepts for the future. This is our goal. Service—The Green Section’s Only Mission A total of 917 courses subscribed to the Visiting Service Program in 1967, and 1,339 direct visits and written reports were made by Green Section agronomists to the subscribers. The organization has now been geared for expansion; both in research and consultation activities. For an annual fee of $225 (for an 1 8-hole course), any USGA Member Club can avail itself of these significant services. The hand of the golf course superintendent and Green Committee Chairman is strengthened by direct visits of agronomists who know golf course requirements. Unbiased recommendations, in­ terpreted research information, and an ex­ change of turf management techniques is the end product of each visit and report. The program has proven itself over the years. The number of supporting clubs con­ tinues to increase, and indeed, has necessi- JAMES L. HOLMES HOLMAN M. GRIFFIN WILLIAM H. BENGEYFIELD JAMES W. TIMMERMAN G. DUANE ORULLIAN A. ROBERT MAZUR fated the present expansion. If your club does not now receive the Visiting Service, it may well be worth considering. No one has a monopoly on knowledge. Evolution, like time, never ceases. Brief Biographies of Newest Green Section Staff Members A. Robert Mazur Born in Middletown, Conn., and moved shortly thereafter to North Kingstown, R.L Graduated from the University of Rhode Island in June, 1963, with a B.S. in agricul­ tural chemistry. Received a commission in the United States Army and served two years as a supply officer at Ft. Ord, Calif. Returned to graduate school in January, 1966, at the University of Rhode Island. Con­ ducted research on turfgrass primarily in the area of weed control. Received M.S. from the University of Rhode Island in June 1968. 1961-1962 Health Physics Technician at National Reactor Testing Station near Arco, Idaho, by Phillips Petroleum Company. 1962-1964 Assistant Territory Manager for the Niagara Chemical Division of FMC Corp, in Yakima, Washington. 1965 Employed by Yakima Farmer’s Sup­ ply Company in Yakima, Washington as a Field Entomologist. 1965-1968 Employed by American Oil Co. as Farm Advisor in Yakima, Washington for 1 ]/2 years; then as Pesticide Formulating Plant Manager at Twin Falls, Idaho and last year as Farm Advisor at Blackfoot Farm Cen­ ter in Idaho. Holds a 10-year membership in the Ento­ mological Society of America as well as a life membership in the Sigma Alpha Epsilon fraternity. James W. Timmerman Born October 8, 1 938, in Monona, la. Reared on poultry and crops farm in Howell, Mich. B.S., 1964, Michigan State University, Soil Began work for the USGA Green Section in Science, (Turf). March, 1 968. M.S., 1968, Michigan State University, Soil Has written several publications on weed Science, (Turf). control in turfgrass. 1964-1968, Graduate Assistant, Michigan Member of American Society of Agronomy, State University, research in turf. Alpha Zeta, Phi Sigma, and Sigma Xi. G. Duane Orullian Born and raised in Idaho Falls, Idaho. Father has been the professional at Pinecrest Golf Club for 33 years. Attended Utah State University and grad­ uated with a B.S. in Entomology in 1959. Later returned for post graduate work, which he hopes to complete in the near future. 1964-1966, Assistant Superintendent, West­ wood Country Club, Buffalo, N.Y.; supervision of golf course; March-October 1964, Detroit Golf Club, section man, maintenance of golf course; March 1 963-September 1963, Walnut Hills Country Club, E. Lansing, Mich., section man, maintenance of golf course; USGA Green Section, April 1, 1968. Member of American Society of Agronomy, Soil Science of America. Veteran (army); married. NOVEMBER, 1968 3 by JAMES B. MONCRIEF, Southern Director, USGA Green Section Rainfall is the original source of water. Rec­ ords show that in Georgia we normally get enough rainfall in one year to cover the entire state to a depth of four feet. This is over one million gallons per acre. In some of the south­ western states it takes several years to receive this much water. About 80 percent of the annual precipita­ tion in Georgia returns to the atmosphere through evaporation from plant and soil sur­ faces and transpiration by plants. Most hy­ drologists often call this the total evapotrans­ piration. The remaining 20 per cent runs off the surface as immediate streamflow, or enters the soil and moves to the ground­ water where it is available for pumping, or later returns as base flow in the streams. Where a dense sod covers the land, less rain (2-3 per cent) leaves as surface water whereas on cultivated soil a high percentage of the water leaves as surface runoff. The type of soil will have much influence on loss of water by surface runoff. Ponds, lakes, or reservoirs are important sources of water for industry, municipalities, and recreation. Groundwater has been used for thousands of years, and streams, springs, and wells no doubt were the first ground water sources used. Archeology of pre-historic people indicates that irrigation, or the appli­ cation of water to lands by artificial methods, is a very old practice. Evidence points to Egypt as its place of origin. Ancient Egyptian paintings and sculptures show that water was bailed up for watering crops at least 4,000 years ago. Modern irrigation was begun in the United States in 1847 by pioneers of Salt Lake Val­ ley, Utah. Since that time, the practice has spread first into the richer and warmer valleys, and then generally throughout the arid part of the West. Golf courses are now being irri­ gated throughout the continental United States. Skinner Irrigation Co. was one of the first to design a sprinkler irrigation system in 1896. There are seven principal methods of ap­ plying water to land: 1. Flooding—running water over a smooth field surface. 2. Furrow—applying water in furrows. 3. Check method—pooling water succes­ 4 USGA GREEN SECTION RECORD sively into checks or rather large pools or squares into which the fields may be divided. 4. Basin—similar to the check method ex­ cept that the basins are smaller. This type is used primarily in orchards. 5. Border method—flood irrigation be­ tween controlling borders or ridges. 6. Sub-irrigation water below the surface accomplished by means of open drain­ age ditches and underground basins. 7. Sprinkler irrigation—application of water under pressure in pipes so that it comes through whirling sprinkler heads as a spray. Most old, established courses of today are thinking of installing irrigation systems of some sort if they have not already done so. There are a few areas where precipitation is suf­ ficient enough and irrigation is rarely needed. Such an area is Highlands, N.C., with a 36- year average of 82.63 inches annual rainfall, and Skamania County near Cougar, Wash., for an 1 1-year average of 1 1 7 inches annual rainfall. At the other end of the rainfall aver­ age is Agua Caliente, Ariz., with an 11-year average of 2.98 inches of rain per year. Hydrology I n the middle ages, people believed that center of the earth. Late in the 17th Century, Edmund Halley, the famous English astrono­ mer, calculated the amount of water flowing in rivers that empty into the Mediterranean Sea and found that their flow is about equal to the water falling in rain and snow on the area drained by the rivers. At about the same time, two Frenchmen arrived at the same con­ clusion. Water is constantly being exchanged be­ tween the earth and the atmosphere. This ex­ change is accomplished by the heat of the sun and the pull of gravity. Water evaporates from wet ground, from the leaves of growing plants, and from lakes and reservoirs and is carried in the air as water vapor. When water vapor condenses, it changes from a gas to a liquid and falls as rain. The rain feeds the rivers and lakes, and the water is carried to the ocean by rivers. The water goes from earth to atmos­ phere to earth again and again. This process is called the hydrologic cycle. Hydrology is the study or knowledge of water. Hydro means having to do with water, and loge is a Greek word meaning “knowledge of.” Water in the Ground H ave you ever wondered where the water comes from which flows merrily along with not a cloud in the sky? Where has it been all the water in rivers flowed magically from the time? One of the principal methods of applying water to turf. Windmills are used to pump fresh water from top of saltwater. In brief, it has been in the ground! It is interesting to know how it got into the ground, how it moves from where it entered the ground to the place where it gets into the streams or rivers, and how long this takes. You might compare the soil surface to a sieve. Water enters the soil and works its way down into cracks, crevices, and holes into larger cavities. On coarse sand or gravel there is fast movement into the earth. How­ ever, when rain falls on clay or fine-grained soils, the passage downward is slow and water may run off the surface. The water going into the soil is called infiltration. Two forces are involved in the movement of water within the soil: capillarity and gravity. Capillarity can work both upward and down­ ward where small particles are close enough together, very similar to cloth used as a lan­ tern wick. When the soil strata are coarse, the water is pulled by gravity and flows down­ ward more or less freely through the spaces. Similarly, water may flow downward through holes made by aerification, worms, or where roots decay. The water continues to move through various layers of soil, rocks, in caverns, gravel strata and from underground streams or lakes. One of the deepest oil wells ever drilled is about 25,000 feet. This is almost 5 miles. Although this is deep, it is insignificant com­ pared to 4,000 miles to the center of the earth. This well has penetrated deeper than the ordinary cracks found in the near surface rocks. The soil or rock which contains or transmits water and is a source of underground water is known as an aquifer. An aquifer is an underground zone layer which is a relatively good source of water. Water can move from aquifer to aquifer, and the amount of water obtained can vary tremendously. One of the largest underground fresh water sources in the United States is in the north portion of Florida. As water passes through different strata, it can collect minerals that affect its taste, color, or odor, and this can vary a great deal within a short distance. How long does it take water to move in the soil? Anywhere from a few feet per year to a few feet per day. It may take hundreds of years for water to travel 20 miles, while in some areas the same distance may have taken months or a few years. In some of the arid parts of western United States water is being pumped that fell as rain during the ice age, or at least 6 USGA GREEN SECTION RECORD 10,000 years ago. Water being pumped from a well could have been stored underground for months, years, or centuries. If the water is pumped out faster than inflow to the storage basin, there is a lowering of the water table, but when the inflow equals the outflow, there is no change in the amount of storage water. There are many places in the United States where the water levels are progressively going down because of overdrafts on the ground water supply. One such area is the Gila River Valley of Arizona; another is the high plains of northwest Texas. Chemicals in Water As water filters through various strata, chemistry can become complex. Rainwater usually contains less than 10 parts per 1 mil­ lion of dissolved matter, or 1 million pounds of water contains 10 pounds of dissolved material. The dissolved material in rivers is usually less than 500 ppm, but some may con­ tain 2,000 or more ppm. Most city water is less than 500 ppm, and any over this is con­ sidered undesirable. Brine water will contain as much as 1 0,000 ppm and is much too salty for use. Sea water contains about 35,000 ppm. The Great Salt Lake contains about 250,000 ppm. Water from some areas of the shallow coastal plain aquifers of the late Pleistocene age generally is low in dissolved solids. In some areas, this water source also has a dis­ agreeable odor caused by hydrogen sulfide. It may have a high iron content as well and is usually classified as hard water. Silver Springs, near Ocala, Fla., has a flow of 500 million gallons of water per 24 hours and removes about 600 tons of dissolved solids (mostly calcium bicarbonate) per day. Shallow water from dune sand along the coast in South Carolina is usually hard and contains dissolved solids. The water becomes softer because of base exchange in which calcium and magnesium ions are replaced by sodium ions resulting in sodium bicarbonate water having a pH of about 7.7 to 8.7. The base exchange has not been definetely identi­ fied, but a likely one is the glauconite, which occurs in formation of the Peedee and Black Creek of South Carolina. Another base ex­ change material in the coastal area is the clay mineral montmorillonite. This gives some of the chemical reactions that can take place while water is in the ground. In other areas, you may find other chemicals in your source of water. Unfortunately many golf courses are being built today without knowledge of the type of water available for irrigation purposes. Before considering any other factor in an improved irrigation system for your golf course, check on the availability, the purity and the amount of water you are going to require. Check your “water sources’’ first! Good streams and ponds can add to the beauty of a golf course and to the members’ enjoyment. The Fate of Herbicides by A. ROBERT MAZUR, Agronomist, USGA Green Section With the widespread and repeated use of chemicals for the control of weeds in turf­ grass, several questions often arise: (1) What happens to the herbicides we apply year after year? (2) How often can we apply these materials without apparent injury to the turfgrass? (3) What effect does the long term use of these materials have on established turf and the establishment of new seedings? (4) What can we do to modify any delete­ rious effects which may occur? In general, herbicides may disappear from the soil in three ways: by chemical means such as hydrolysis, oxidation, and photodecompo­ sition; by physical means, such as volitilization, leaching and absorption; and by biological degradation. Under field conditions, rate of application, type of soil, nature of the material, weather, and cultural practices all have a direct bearing on the life of herbicides in the soil. Microorganisms The single most important factor leading to the breakdown of herbicides is soil micro­ organisms. Biological degradation is hastened by those factors favoring the activity of the soil microorganisms. Environmental factors such as temperature, moisture, oxygen supply and organic matter content determine the rate at which biological decomposition takes place. The optimum temperature range for most soil organisms is between 75 and 90°F. The principal microorganisms in the soil are algae, fungi, actinomyces and bacteria. As the pH of the soil varies, the activity of certain groups of organisms is enhanced and others is retarded. Bacteria and actinomyces are favored by pH's above 7.0 while fungi are most active at pH’s below 5.5. The pH, how­ ever, seems to have little effect on the total microbial population. Those microorganisms most favored by conditions increase rapidly, and therefore the population is in a constant state of fluctuation. It has been shown that organic soils re­ quire higher application rates of herbicides for effective weed control than mineral soils. The larger microorganism population and the greater degree of internal surface area have been found to be responsible for this re­ duction in activity. Enzymatic capabilities of microorganisms are wide and varied; however, soil micro­ organisms are not infallible. Although resist­ ance to biological decomposition means a greater period of weed control, it also pre­ sents the potential hazard of residue accumu­ lation following repeated use. The resistance of organic materials to decomposition is ev­ idenced by the present accumulation of de­ tergents in drinking water sources. This should be a caution to us on the use of our turfgrass herbicides in excess. Chemical Breakdown The nature and properties of chemicals affect such characteristics as vapor pressure, water solubility, and melting point, which are all important factors in determining the length of time that the herbicide will be effective in the soil. Those materials which are volatile or readily leached are only effective for short periods of time. An effective preemergence herbicide must remain in the top one-half inch of the soil in sufficient concentration to inhibit the development of weed seedlings. This means that the chemicals should be some­ what immobile and stable so as to cover the entire period of weed seed germination. One of the common misconceptions is that preemergence herbicides suppress germina­ tion. Actually, preemergence herbicides do not stop germination, but are phytotoxic to the newly developed weed seedlings. One of the newer chemicals (siduron) is so specific that it can be used in the seedbed to eliminate weed seedlings; however, it is not deleterious to the germinating turfgrass. Proper Application Herbicide placement is one of the most influential factors governing effectiveness. In the case of the preemergence materials, we want to create a seal in the top half inch of the soil. This can best be accomplished with the granular formulations which have shown 8 USGA GREEN SECTION RECORD more favorable results than either the emul­ sifiable concentrate or the wettable powders. It is important to make the application in at least two directions to insure uniform distri­ bution. Once the material has been applied, this seal should not be broken with any operation such as thatching or aeration which could bring untreated soil and weed seeds from a lower depth into the germination zone. Aeration should be accomplished in the spring prior to application of the chemical, or else delayed until after the period of weed seed germination in the fall. In weed control, we have to discount the adage; “If a little bit is good, a whole lot is even better.’’ Many serious problems have developed when this adage has been applied to selective weed control with herbicides. Bensulide, DCPA and siduron all have shown effective crabgrass control. Studies also in­ dicate that there appears to be no accumu­ lation of these materials in soil receiving four annual applications. However, bensulide and siduron were shown to move downward in the soil profile after several weeks. Bensulide was found to persist in the soil several years from one application at the recommended rates. Always Some Injury? All of the preemergence crabgrass ma­ terials have been shown to cause some degree of injury to established turfgrass. In some cases injury was associated with only a par­ ticular grass or grass species, but in general they all suppressed the development of roots and stolons to some degree. Therefore, it is advisable to use herbicides only when neces­ sary, and then never more than two years in succession. Charcoal Cancelling After applying a herbicide a situation often develops in which it becomes necessary to overseed. This could normally delay your op­ eration anywhere from 12 to 16 weeks. It has been found that an application of 200 pounds of activated charcoal per acre during the seeding operation will nullify this residual effect of the herbicide. Charcoal is available in many forms. It can be applied as a granular material, or the dust can be mixed with water and sprayed on the seedbed. In order to realize its full value the charcoal should be thoroughly in­ corporated into the seedbed by raking in at least two directions. In conclusion, we must say that weeds are primarily a problem in those areas which lack good turfgrass coverage. As in the past, the most reliable weed control program is still one that concentrates on the maintenance of good turfgrass cover. Where do all the seedies go? To my course, every one! NOVEMBER, 1968 9 Low Temperatures and Poa Annua by DR. JAMES B. BEARD, Michigan State University Editor's note: In an earlier article, “Effect of Temperature Stress on Poa Annua,” Green Section Record, July, 1 968, Dr. James Beard pointed out the problems of high temperature stress on Poa annua. Here he covers the other side of the coin and brings us up to date on his oustanding studies of “Low Temperatures and Poa Annua.” As stated earlier, the actual temperature of a turfgrass plant or its individual parts is de­ termined by its surrounding environment; i.e., the soil temperature for underground parts and the air temperature for above ground parts. The “optimum temperature’’ is that at which a particular plant process occurs at the highest rate. Optimum temperatures will vary depending upon the a) age of the plant, b) stage of development, c) specific plant organ involved, d) physiological condition of the plant, e) duration of the temperature level and f) variation in other environmental factors. Low Temperature Stress As temperatures are decreased below the optimum, there will eventually be a point at which growth will cease. However, respiration and photosynthesis have been found to occur in roots and shoots of turfgrasses at temper­ atures near 32 degress F. If temperatures con­ tinue to decrease, a point is reached where direct low temperature kill will occur. Research at Michigan State University shows that an­ nual bluegrass is a turfgrass species which is relatively susceptible to low temperature kill compared to others, such as creeping bent­ grass and Kentucky bluegrass (Figure 1). The mechanism of direct low temperature kill involves mechanical disruption of the pro­ toplasm caused by ice crystals. In general, the killing temperature increases with the hydra­ tion level or water content of the tissue. The relative low temperature tolerance of annual bluegrass will vary during the winter season. Maximum winter hardiness is achieved in late December, followed by a slight decrease in hardiness in late January, with a continued decrease in hardiness to a minimum level at the time of spring thaw. Therefore, low tem­ perature kill is most likely to occur during the late winter, early spring freeze and thaw pe­ riod when the crown tissues are at a higher hydration level. It should be pointed out in relation to direct low temperature kill that the primary concern is the actual soil temperature rather than the air temperature. The critical tissues which must survive are the crown meristematic tissues. Leaf and root kill is of no concern since these tissues can be readily replaced by new growth from the crown. Thus, as long as temperatures in the crown area remain above the lethal level, no critical kill of the turf will occur. Direct low temperature kill appears to be most common in an intermediate belt across Wisconsin, Michigan, New York, northern Illi­ nois, and in certain areas of New England. This is an area that is subjected to extended periods of freezing and thawing and also has a higher potential for hydration of the crown tissues. The comparative low temperature tolerance of annual bluegrass and Toronto creeping bentgrass is shown in test plants sampled in mid-December. (Figure 1). TORONTO CREEPING BENTGRASS ANNUAL BLUEGRASS Of more immediate concern to the profes­ sional turfman are methods to eliminate direct low temperature kill problems. Actually, there are no guaranteed methods of avoiding low temperature kill, but practices are available which will minimize the chance of injury. De­ tailed studies at Michigan State University show that excessive late fall nitrogen fertili­ zation should be avoided because this will stimulate growth and increase the hydration level of the crown tissue. One should also be sure that adequate levels of potassium are present. It appears that a relationship of three to four units of nitrogen to one unit of potas­ sium will provide the proper nutritional bal­ ance to insure maximum low temperature sur­ vival. Other factors of concern are proper surface and internal soil drainage in order that free water can be drained from the vicinity of the crown tissue as rapidly as possible. If the an­ nual bluegrass plants are permitted to stand in water for an extended period of time, the hydration level of the tissue will increase. If this is then followed by a very sharp freeze to temperatures of below 20 degrees F., the potential for direct low temperature kill is quite high. Thatch should also be avoided as it will contribute to increased low temperature kill. One final consideration is avoiding traffic over the turfgrass area during wet, slushy periods. If a sharp freeze occurs, this con­ dition can result in severe turfgrass injury. Ice and Snow Covers Extended periods of ice and snow coverage sometime occur during winter period. The pos­ sibility exists that an extended period of high density ice coverage could impair gaseous diffusion to the point that the turf could be injured through either (a) suffocation caused by a lack of oxygen for respiration, or (b) toxic gases which have accumulated adjacent to the living tissues. Both field and controlled climate studies have been conducted at Michigan State Uni­ versity to clarify this type of injury. Based on these studies, one must conclude that injury caused by the ice cover itself is a rare occur­ rence. In general, most turfgrass species are rel­ atively tolerant to extended periods of ice coverage. Annual bluegrass is less tolerant than many others. For example, injury to an­ nual bluegrass may occur under ice sheets A demonstration of the comparative survival of Toronto creeping bentgrass, Kentucky blue­ grass and annual bluegrass when they were completely sealed in ice for 120 days at 25° F. (Figure 2). Note kill of the annual blue­ grass at right. which have been in place in excess of 60-70 days. In contrast, bentgrass has survived as long as 120 days under an ice cover (Fig­ ure 2). The question frequently arises, “Should I re­ move the ice and snow cover from my greens and tees?’’ Basically, this is a good practice, although the reason for which you may be re­ moving it may not be the correct one. By re­ moving a majority of the ice and snow from a green, you are essentially mechanically re­ moving the water from the green in a frozen state. Thus, during the thawing period, this water will not accumulate in the vicinity of the grass crown tissue, cause an increase in the water content of the tissue, and result in a greater chance of injury due to low tem­ perature kill. In general, one should not com­ pletely remove the ice and snow cover. It is best to leave between one-half and one- quarter inch of snow cover to avoid winter atmospheric desiccation problems which may occur if the turf is exposed to drying winds for extended periods of time. In summary, annual bluegrass is relatively susceptible to both high temperature and low temperature stress, compared to many of the other permanent, perennial cool season turf­ grasses being used. These are two reasons why annual bluegrass is objectionable in qual­ ity turfs. However, the prolific seed produc­ tion and the presence of large quantities of Poa annua seed in the soil insures rapid re­ establishment of a turfgrass stand following any temperature kill. Studies are continuing at Michigan State University in order better to understand high and low temperature stress mechanisms of turfgrass, with the ultimate hope of developing turfgrass species which have greater heat and cold tolerance. NOVEMBER, 1968 11 When Poa Annua and cool season grasses fail in intense heat, bermudagrass is at its best, as evidenced by the trial strips in this fairway in the Transition Zone. Bermuda grasses in the Transition Zone by DR. ELWYN E. DEAL, Turf Specialist, University of Maryland Problems? You bet we have them in the transi­ tion zone, probably better known as the “crab­ grass belt.’’ We have one asset which in some cases might be a liability. We can grow most of the cool-season and most of the warm-season grasses (advantage), but none of them are well adapted to the area (disadvantage). Per­ haps our greatest problem is that we spend too much time trying to grow all of them, when we should be concentrating on a select few. The purpose of this article is not to promote bermudagrasses for fairways and tees, but rather to point out some of the advantages and disadvantages of using them. First, the advantages. When managed properly, bermudas are vigorous, fast-growing, deep-rooted grasses. They provide a dense, uniform, non-clumping turf that recovers quickly from injuries such as traffic, divots, etc. Even when dormant they provide a good playing surface. Bermudas have their best growth during the hot summer months when most other fairway grasses are easily damaged. They can be cut close—down to % 'nc^—which delights the golfers. During their growing season they are extremely tough competitors with weeds, and usually keep them under good control. Bermudas respond well to good manage­ ment, especially fertilization, and provide a beautiful playing surface throughout the late spring, summer and early fall months. Bermu­ das in this zone usually have few insect and disease problems. They are also very heat- and drought-tolerant. During dry periods they remain lush and green long after most other grasses have turned brown. Two disadvantages weigh quite heavily against the bermudas: winter dormancy and winterkill. Along the northern limits for ber­ mudas, this grass may be dormant, or partially so, for six or seven months of the year. Many golfers object to playing on brown turf, al­ though most of those who have objected agree quite readily that the playing surface was perfectly satisfactory except for color. Secondly, probably the most severe draw­ back for bermudas is the problem of winter- kill. All varieties which are commercially avail­ 12 USGA GREEN SECTION RECORD able now lack sufficient winter hardiness to make them completely dependable. About once every five to ten years we have a very severe winter that takes out most of the ber- mudas. All of the winterkill problems cannot be attributed to lack of inherent winter hardi­ ness, however. I am suspicious that after three or four successful years we become lax in managing these grasses. We have known for many years now that a lush, tender grass is much more susceptible to winter injury than the same grass when it has had a chance to harden off before winter. Late fall fertilization with nitrogen, especially when there is an imbalance of nitrogen with phosphorus and potash, increases the likeli­ hood of winter injury. We get by with it for two or three years and keep on using more nitrogen late in the year. Then we have a bad winter and lose the bermuda. Our natural re­ action then is to blame it on the grasses. The bermudagrasses available today are not as winter-hardy as we would like to have them, but a lot can be done through good management to reduce the risk of winterkill. As indicated earlier, the fertilization program can easily be altered if necessary. Many golf course superintendents in the transition zone apparently fail to realize the drastically differ­ ent type of management programs that are needed for the bermudas and for the cool­ season grasses. Summer fertilization and thatch removal are two good examples. One other problem that threatens bermudas is the “spring deadspot’’ disease. The real im­ pact of this problem is difficult to evaluate in the transition zone because of the ups and downs in use of bermudas. Another indirect threat, too, is the elabo­ rate irrigation systems now available for golf courses. This, coupled with the development and use of sophisticated herbicides which con­ trol or prevent weed invasion, makes it easier to grow Kentucky bluegrasses on fairways. Several new bermuda and Kentucky blue­ grass selections are currently being evaluated which might help overcome some of the prob­ lems in the transition zone. Most of them need more study before we will know how much of a solution they will provide. If new Kentucky bluegrasses can be found which will tolerate close mowing (% to 1 inch) and summer heat, they will likely receive the nod over bermuda­ grasses for most fairways in this zone because of their longer “green’’ season. Progress is being made with the winterhardiness problem in bermudas, but the one of long winter dor­ mancy periods will likely be with us for a long time. Bermudagrass spreads quickly to cover from stolons and rhizomes. NOVEMBER, 1968 13 USGA GREEN SECTION RECORD 40 East 38th Street, New York, N. Y. 10016 TURF TWISTERS NITROGEN VERSUS HAIR Question: I was recently shown a list of the approximate nutrient content of waste materials and note that hair is from 8-16% nitrogen. Can this be used as fertilizer? (New Jersey) Answer: Hair is used in making nitrogenous tankage and wet base goods. However, it is too slowly available to be suitable as a fertilizer. Hair may also be used in a compost to good advantage. FERTIGATION VERSUS DRY FERTILIZER Question: What are some of the pros and cons of applying fertilizers through the irrigation system? (California) Answer: We have seen this practice on a number of golf courses over the years. Yet one of the main problems with this technique lies in the fact that it is only as effective as the irrigation system, and most golf course irrigation systems are incapable of uniform .coverage. Irrigation patterns are dis­ torted by the wind, water pressure differences, sprinkler head efficiency, fixed objects such as trees or shrubs, etc. Other problems that have been encountered in the past include terrain unevenness and runoff, different fertilizer requirements for different areas (tees, greens, fairways, roughs, etc.), and corrosion of metal parts in the irrigation system. Finally, there are some who believe that constant “force feeding’’ of turfgrasses does not always produce the best golfing turf. Fertigation has been successful in many areas of agriculture. On golf courses, it has yet to prove its long range advantages over dry fertilizer application. RYEGRASS VERSUS THE CIVIL WAR Question: By the end of this season, our practice tee looked as if the Civil War was fought over it. Is there any way to grow grass on a medium to small size practice tee? We have no room for expansion. (Nevada) Answer: Grass won’t grow on a busy street. However, there may be a way to alleviate the problem. Reasonable success has been achieved by over­ seeding tees every month of the growing season with annual ryegrass. About 20 pounds per 1000 square feet is suggested. It is inexpensive, quick to germinate and at least gives some grass cover until that next divot is taken.