PROCEEDINGS OF 7TH NNNURL IIORTHUJEST TURF COIIELRRIICE 1953 S P O N S O R E D BY PACIFIC NORTHWEST TURF ASSOCIATION ft no THE STATE COLLEGE OF WASHinGTOn TABLE OF CONTENTS DIRECTORS AND OFFICERS I PROGRAM II THATCH ON GOLF GREENS Tom Mascaro 5 H. S . Telford 7 Jack Meiners 9 Donald Peterson 11 . . . C h a r l i e Wilson 15 PHYSICAL PROPERTIES OF SOILS WITH SPECIAL REFERENCE TO WATER... MANAGEMENT .Walter Gardner 20 ESTHETIC FACTORS OF PLANTING DESIGN W. S. Summers 27 MERION BLUEGRASS Arden Jacklin 30 Paul Brown 32 Lester Orton 35 William R. Burnett 37 K. J . Patterson 39 INSECT CONTROL ON TURF RESULTS OF THE FUNGICIDE TRIALS - 1952-53 PROGRESS REPORT OF THE PEARLWORT CONTROL PROJECT WATER MANAGEMENT TURF FERTILIZER CONTROL OF VEGETATION ON OREGON HIGHWAYS KRILIUM EXPERIMENTS TURF FIELD TRIP - 1 9 5 3 . . . Compiled Courtesy of WEST POINT PRODUCTS CORPORATION West Point, Pennsylvania NORTHWEST TURF ASSOCIATION - OCTOBER 1952 BOARD OF DIRECTORS Edward Fluter George Hammar John Harrison Ivan W. Lee Jay Merrick James O* Brien Glen Proctor Carol Wieting 923 N. E. 155th, Portland, Oregon 2101 Cemetery Road, Caldwell, Idaho Hayden Lake C. C . , Hayden Lake, Idaho 705 Fourth Avenue, Seattle, Washington 7201 Hannah Pierce Rd., Tacoma, Washington 1915 Capilano Rd., North Vancouver, Canada 11411 Military Rd., Seattle, Washington 13504 21st N. E . , Seattle, Washington OFFICERS - 1952-1953 Ed Fluter Jim O'Brien A. G. Law Henry Land President Vice President Secretary Treasurer — 9212 Winona Avenue, S. S. Tacoma 9, Washington Ivan W. Lee Turf Associations's four year representative on the Agronomy Advisory Board. PROGRAM TUESDAY September 22, 1953. Morning 9:00 - 10:00 — Registration. Room 213, Compton Union Building HENRY LAND and A. G. L A W Chairman: JAMES O'BRIEN, Vice President, Pacific Northwest Turf Association 10:00 - 10:15— Welcome, M. T. BUCHANAN, Director, Agricultural Experiment Stations, WSC, Pullman, Washington 10:15 - 11:00 — Turf Management. O. J. NOER, Sewerage Commission, City of Milwaukee, Milwaukee, Wisconsin. 11:00 - 11:30 — Thatch on Golf Greens, T O M MASCARO, West Point Products Corporation, West Point, Pennsylvania 11:30 - 11:45 — Insect Control. H. S. TELFORD, Chairman, Department of Entomology, WSC, Pullman, Washington Afternoon 1:30 - 3:00 — Business Meeting. ED FLUTER, President, Pacific Northwest Turf Association, 923 N. E. 155th, Portland, Oregon. 3:15 - 4:00 — Reports of Research. JACK MEINERS, Pathologist, WSC, Pullman, Washington; and DON PETERSON, Agronomist, Western Washington Experiment Station, Puyallup, Washington 4:00 - 4:30 — Questions Annual Banquet — Compton Union Building WEDNESDAY September 23, 1953 - Morning 8:30 — Sectional Meetings, Compton Union Building Speakers for the two Sections will be shifted at 10:15. Greens Management Room 216 Chairman: KEN MORRISON, Extension Agronomist, WSC, Pullman, Washington Water Management, CHARLIE WILSON, Western Director, USGA, P. O. Box 241, Davis, California Water Movement in Soils. W A L T E R GARDNER, Soil Scientist, WSC, Pullman, Washington Landscape Design. W. S. SUMMERS, Horticulturist, WSC, Pullman, Washington Merion Blue Grass. ARDEN JACKLIN, Jacklin Seed Company, Dishman, Washington Parks Cemeteries, Highways Management Room 207 Chairman: B. R. BERTRAMSON, Chairman, Department of Agronomy, WSC, Pullman, Washington Weed Control. HENRY W O L F E , Extension Weed Specialist, WSC, Pullman, Washington HI Turf Fertilizer. PAUL BROWN, The Charles H. Lilly Co., Seattle, Washington Roadside Turf. LESTER ORTON, State Highways Commission Salem, Oregon * Krilium Experiments, WILLIAM R. BURNETT, Montsanto Chemical Company, 4224 N. E . , 29th Street, Portland 11, Oregon Afternoon 1:30 - 2:30— Field Trip to Grass Research Plots. KENNETH PATTERSON, Agronomist, WSC, Pullman, Washington 3:30 — Leave for Hayden Lake -o- THATCH ON GOLF GREENS T O M MASCARO West Point Products Corporation Control of grain, thatch and mat is an important part of turfgrass management. All these undesirable conditions arise from the same factor --an excessive amount of growth that is not removed by ordinary mowing practices. The golfer complains about the grain on the greens, that interferes with the accuracy of hisv putting. The superintendent is bothered by thatch and mat because they complicate every phase of mainteiance. When does grass growth become a problem? We aerify, fertilize and water to stimulate healthy, dense grass growth. We choose aggressive grasses that grow fast and heal quickly. Ordinary mowing removes the tips of the grass blades and controls the height of growth. But ordinary mowing does not remove the accumulation of surface stems and old leaves at the base of the plants. It is this accumulated growth that causes the headaches. The accumulation between the new grass growth and the surface of the soil interferes with proper mowing. When the mower is set to cut at 3/16 or 1/4 inch, it cuts at this height above the thatch layer -- not above the soil. You no longer have the close-cut greens the golfers desire. The longer grass lies over, the ball skids across the blades and controlled, accurate putting is impossible. When the golfers begin to complain, the superintendent has to do something to correct the situation. The most direct way of getting rid of the trash would be to plow it under and begin all over again. Dr. William Daniel of the Midwest Regional Turf Foundation often points out that the Indiana farmer is fortunate in that he can bury his mistakes every year when he plows. But the superintendent cannot plow up the greens; he must live with his mistakes. Thatch does not develop overnight. It builds up a little at a time. You may not notice what is happening until the thatch has become heavy enough to be a major headache. It is better practice to observe the condition of the greens and control the thatch before it becomes serious. A sharp knife with a long blade is the only equipment needed to check on thatch build-up. Cut a plug from the green and you will see at once how great is the distance between the growing grass tip and the soil. If a heavy thatch layer exists, it is likely that very little water is reaching the soil. The thatch is as good as a roof to shed water. Aerification will make openings to allow the water to pass through the thatch and into the soil. This is a quick way to allow water to get to the dry spots. But prevention is better than cure. A program should be instituted to get rid of existing thatch and prevent future accumulations. Thatchnot only sheds water and fertilizer. It is a breeding place for the organisms that cause plant disease. An accumulation of trash makes unsanitary living conditions for grass as well as people. Moreover, it has been shown that disease occurs chiefly on the older leaves of the grass. Healthy new growth is less susceptible. If old growth is allowed to accumulate at the base of the plants, disease attacks are more likely to occur. The problems caused by thatch do not end here. Thatch keeps out the moisture and air needed for decomposition. As leaves and stems die they cannot be decayed into soil humus. Instead they forma partially decomposed organic layer, which many superintendents call "under-neath mat". This felt-like layer is even more impermeable to water. Although thatch and mat are composed of the same materials, correcting these two conditions must be done by different methods. A surface thatch can be removed mechanically with hand or power tools. The underneath mat cannot be removed by surface working tools. Aerification to break it up and mix the material with soil is the only way to correct this condition. Let's consider first the tools for removing surface thatch. Over the years many tools have been made for this purpose. Superintendents have used hand rakes with flexible or rigid teeth. Surface spiking tools have been used in the attempt to remove thatch. Many superintendents have devised their own tools to be pulled across the greens to remove thatch material. Ellis Van Gorder,Stanford University Golf Course, devised a tractor-pulled surface thatch remover composed of two rows of stable brooms with a row of flexible wire teeth between them. Ted Weisser, Scranton Country Club, Pennsylvania, has a home-made tool composed of two rows of closely spaced flexible steel teeth, that can be pulled over thatched areas with a small power unit. Toro Manufacturing Company had a tool many years ago that could be installed in one of their mowers. It consists of a series of kidney-shaped knives that rotate and cut slices into the turf. As the importance of thatch control becomes recognized, many tools will be devised to help control it. We at West Point have been aware of the problem for several years. Professor Musser, Pennsylvania State University, suggested many times that an efficient power tool should be developed to help control surface thatch. Many superintendents recognized the need for better tools to control surface thatch, ¿thatch control has not been satisfactory in the past, it was because there were no adequate tools to control it. At West Point we believed the ideal thatch control tool should combine efficient operation with satisfactory results. Hand tools are too slow and costly for more than once or twice a year use. Also, rakes and brushes roughen the putting surface. So we came up with the Verti-cut, a vertical mower that does its work with sharp blades rotating at high speed. We put power on the Verti-cut so it would be practical to use it at frequent intervals. And the sharp blades are designed to "shave" off the thatch, without any tearing or pulling to roughen the surface. The Verti-Cut is as perfect as we can make it for the removal of surface thatch. But it is not intended to remove the underneath mat. Underneath mat can be overcome only through bacterial decomposition. Conditions must be made favorable for bacterial activity. The bacteria exist in the soil. Aerification mixes soil with the organic layer and it admits the oxygen and moisture needed by the bacteria. Frequently lime is needed to assist decomposition. The organisms that break down thatch use nitrogen, and will compete with the grass for available nitrogen. You may notice a yellowing effect on the turf when decomposition is active. An application of nitrogen will supplement the supply in the soil and provide food for the grass as well as the bacteria. It should be remembered that thatch and mat build up slowly. And it will take time to overcome them, too. Donftbecome impatient and try some drastic operation to get rid of the material all at one time. A long range program should be put into effect to bring about gradual control, with a minimum of inconvenience to the players. -o- INSECT CONTROL ON TURF H. S. TELFORD Dept. of Entomology, State College of Washington, and Carl A. Johansen Chlordane is one of the most versatile insecticides for turf insect control. Not only can it be used as a soil treatment, but it is also effective for certain species of insects occurring on the oliage or on the crown. Turf managers should seriously consider pre-planting treatment of soil with DDT or Chlordane for such insects as wireworms, white grubs, and related soil-inhabiting insects. A relatively new insecticide which will gain more widespread use is a systemic material called Systox. While it may not have widespread use on turf insects per se, turf managers will find it particularly useful to control aphids, mites, and perhaps other sucking insects on ornamental plantings. The chief value of this material is its ability to be translocated in the sap of the plant, protecting foliage for considerable periods of time. The plant remains toxic because rains, sprinklers, wind, etc., do notremove this protective residue. It is not recommended on gardens or food crops as the problem of the toxicity of residues has not been fully evaluated. Hazards from exposures must also be guarded against and precaution should be taken similar to parathion and other related toxic phosphate insecticides. Insecticides 1. Wettable powders - composed of toxicant, diluent powder and wetting agent. Must be kept agitated to keep it in suspension. 2. Dust - composed of toxicant and diluent. Applied dry. 3. Emulsifiable concentrate - composed of toxicant, solvents and emulsifier. Forms a milky emulsion that doesn't need agitation. Various toxicants are used in insecticides. Different poisions act in different ways, and some are more effective than others against specific pests. The inorganic toxicants include lead arsenate, sulfur and selenium. Their toxic action occurs in the stomach or intestine. They are moderately toxic to warm blooded animals. Plants often are susceptible, too. They are used mainly for chewing insects. Botanicals, or plant materials, include nicotine and rotenone. They usually are very low in toxicity to warmblooded animals and to plants. They are, therefore, excellent for household and livestock sprays. The chlorinated hydrocarbons include DDT, DDD, Chlordane, Toxophene,Ovotran, and Aramite. These chemicals act mainly through contact action. They have long residual action and can give some trouble to livestock. They are very effective against many insects, with the exception of Ovotran and Aramite which are specific for mites only. The organic phosphates include Parathion, TEPP, Systox, Pestox, Malathion and Dithione. As a group they are toxic to warm blooded animals. But they break down quickly so there is little danger except when applying. They have excellent contact and fumigant action. As a group they are most effective against aphids and mites. Parathion is effective against the widest range of pests. Malathion is excellent against mites and aphids. It is similar to Parathion, but less toxic to warm blooded animals. -o- RESULTS OF THE TURF FUNGICIDE TRIALS - 1952 - 1953 WASHINGTON AGRICULTURAL EXPERIMENT STATIONS PULLMAN, WASHINGTON Jack P. Meiners Fungicide screening trials on snow mold control were conducted at Washington in 1952 in cooperation with the National Cooperative Turf Fungicide Trials. These trials were initiated at this station in 1951, when 15 fungicides included in the screening test, were evaluated for snow mold control. The unusually heavy infestation of the disease, which occurred in 1951 subjected these fungicides to a severe test and those which gave little or no control were not included in the 1952 trials. One fungicide (Phenyl Mercury Acetate Solubilized No. 10) has been added. As in the previous year, the trials were conducted on golf greens at two locations: one at the Indian Canyon Municipal Golf Course in Spokane, and the other at the Washington State College Golf Course in Pullman. In both locations the turf consists of Seaside Bent and was fertilized for the final time in August, f52. In Spokane, the chemicals were applied in mid-November to greens which were frozen. Five by ten foot plots in duplicate on each of two greens were used, but snow mold developed on only one green. Each of the eight fungicides was applied at two dosages. In Pullman, eleven fungicides were applied in late November to frozen greens, using 8 x 80 foot plots, with one plot of each fungicide on each of three greens. In both locations, application of the fungicide was made either in dry for musing sand as a carrier (10 qts. /1000 sq. ft.) or as a spray using water as a diluent (5 gals. /1000 sq. ft.). In general, heavier dosages of materials were used in 1952, because the lighter dosages used in 1951 failed to give complete control. In spite of very little snow cover, abundant snow mold developed on the untreated plots in both Pullman and Spokane in the winter of 1952-53 so that a good test of the fungicide was obtained. In Pullman, and on some of the greens in Spokane, the disease was associated primarily with Fusarium nivale; whereas, on the green on which the plots were located in Spokane, Typhula itoana was the dominant organism. Disease readings were taken early in March, 1953, and were recorded as per cent of the turf showing symptoms of snow mold. The results are summarized in the accompanying table. The results obtained in 1952 agree very closely with those obtained in 1951. In both years and both locations, the liquid phenyl mercuries (PMAS, Puraturf, Phenyl Mercury Acetate Solubilized No. 10, Tat-C-Lect) were outstanding in reducing the percentage of snow mold. Cadminate, used at much heavier dosages this year, also gave excellent control at Spokane, although some injury to the turf was evident at the heavier dosage (4 oz.) This same material ranked just Effect of Fungicides on Per Cent Snow Mold at Pullman and Spokane, Washington in 1952-53 Dosage per 1000 sq. f t . Treatment Method of Application Per Cent Snow Mold 1 Pullman Untreated Phenyl Mercury Acetate ¿48.0 Solubilized No. 10 Tat-C-Lect 10$ PMAS 10% Pur a turf 6$ Cadminate Calo-clor Special Semesan Puraturf GG Calocure Spergon Tersan 75 2 2 2 3 2 3 5 1 3 6 oz. oz. oz. oz. oz. oz. oz. oz. oz. oz. 6 oz. wet wet wet wet wet dry wet wet dry wet wet 1.7 1.7 1.6 2.0 3.8 ¿1.8 9.6 10.6 17.5 35.5 38.0 Spokane^ Untreated 26.7 2 oz. ¿4 oz. wet wet 0.0 0.0 Phenyl Mercury Acetate Solub. No. 10 Phenyl Mercury Acetate Solub. No. 10 . 1 pt. . 2 pt. wet wet 1.5 PMAS 10$ PMAS 10$ .1 pt. . 2 pt. wet wet 3.5 Tersan 75 Tersan 75 3 oz. 6 oz. wet wet ¿4.0 Calo-clor Calo-clor 2 oz. 3 oz. dry dry 3 oz. Cadminate Cadminate 0.0 0.0 1.5 5.7 ¿4.0 6.2 Calocure Calocure h oz. dry dry Spergon Spergon 3 oz. 6 oz. wet wet 2.2 Special Semesan Special Semesan 3 oz. 6 oz. dry dry 17.5 9.7 ^Pullman - average of three replications Spokane - average of two replications 2 Dominant organism Fugarium nivale 3 -^Dominant organism Typhula itoana^ U-7 6.7 behind the phenyl mercuries at Pullman, Calo-clor also reduced snow mold percentages considerably at both locations, but ranked well behind the phenyl mercuries in giving efficient and consistent control of the disease. As in 1951, Tersan was effective in Spokane, but ineffective in Pullman. The remaining fungicides tested did not provide adequate control of the disease. In an additional trial conducted at Pullman, to determine the minimum effective dosage of PMAS required to control snow mold, it was found that one ounce in five gallons of water per 1000 square feet did not provide as good control as did two ounces, but that three ounces provided no additional control. Where one-half gallon of water per 1000 square feet was substituted for five gallons of water as a diluent no difference was noted in degree of control obtained. -o- PROGRESS REPORT OF THE PEARLWORT CONTROL PROJECT AT THE WESTERN WASHINGTON EXPERIMENT STATION Donald R. Peterson Among the many troublesome weeds that are prevalent on golf courses throughout the Pacific Northwest none are more widespread or persistent than pearlwort (Sagina procumbens.) For years golf course superintendents have attempted to combat this perennial pest by removing the infested portions of their greens by means of cup-cutters or other similar devices and resodding these areas with pearlwort-free turf, an operation that is both costly and time-consuming and frequently ineffective. Certainly no aspect of greens management is more deserving of the attentions and facilities of agronomic research than the problem of pearlwort control. With this object in mind, a study, sponsored jointly by the Pacific Northwest Turf Association and the State College of Washington, was initiated to discover ways and means whereby an effective control of this weed might be obtained. In the fall of 1951 a seedbed, built up of equal parts of a well-decomposed peat, sawdust, sand and the parent soil (an impervious clay) to a depth of 12 inches, was constructed. These materials, together with sufficient lime to bring the soil reaction to approximately 5.6, were mixed thoroughly. The green, 4000 square feet in area, was then seeded to a mixture of Colonial bentgrass and creeping red fescue. In the following spring, four species of plots, each series including eleven 5* x 10T plots, were laid out. Thirty plugs of sod were removed from each plot and these were replaced by plugs of pearlwort which were obtained from golf courses in the area. The turf management, including watering, fertilizing, and mowing, tcwhichthis experimental area has been subjected during the course of this study has been similar to the management practices generally employed on golf greens in the western Washington area. Ten treatments, comprising the most promising of a number of materials tested in a preliminary study conducted in the greenhouse and the recommendations made by weed and turf specialists from the various cooperating agencies, have been studied in replicated plots during the past two years. In addition, check or no treatment plots were also included within the scope of this experiment. The treatments, form, rate, and time of supplication, and the results obtained are presented in tabular form on the following page. Bear in mind that in developing a control for pearlwort, the objective was to find a material or combination of materials that would not immediately kill or burn out the weed, causing severe discoloration and disfigurement to the turf, but would weaken it to such an extent that the desirable grasses might gradually "crowdff it out of the turf. The only treatment that satisfied these requirements was a combination of sodium arsenite (1/2 oz. per 1000 sq. ft.) mixed thoroughly with an organic fertilizer (5-4-0); the mixture was then applied at biweekly intervals at the rate of 16 pounds per 1000 square feet. This treatment not only reduced the infestation of pearlwort, but also largely eliminated annual bluegrass (Poa annua) from the turf. Sodium arsenite, applied in the same manner at the rate of 1/4 oz. per 1000 square feet, was not nearly so effective in reducing the infestation of pearlwort. Spray applications of 2,4-D checked the growth of pearlwort and broad-leaved weeds alike, however, this effect was accompanied by a severe burning of the bentgrass, particularly at the heavier rate of application. Chlordane, applied as a spray at two rates, was neither effective as a control for pearlwort nor for other broad-leaved weeds that encroached into the plot area. Chlordane, mixed dry with an organic fertilizer and applied in that manner, was somewhat more effective. Supplemental applications of commercial nitrogen fer tilizer improved the general appearance of the turf, but at the same time stimulated markedly the growth of pearlwort. CO o i CL H * p O 33 H-1 O hi CL g £ << £? O g o CL CO hi 0 0 *T3 m co8 N o co p o "g- £ 0 P. I 0 i—1 CO 0 I—1 CO I—1' CO Ö Ö CO V« CO V. 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H *4~> tí O • - tí & O .H |to o a) gl CO i 0 ^?A ¿Si s¿1 gs S S 0 5 3 4h tí O O ^ 4-i 2. £r>tí »Ä Tí >&a 0 S© O tí o tí-» 0) o co •rH 3 0 tí >> r-H tí 0 0 § í>> tí o O £ 0 T* Sodium arsenite Nitrogan: § O Sì H 0) -s a a 0 tí 0 S? - a a) £ «S o O ^ a) -3] Od & * I Lí m ft ft ft o 2 tí©«M 33 cd ¡H S O ft o a >» >> O 0) O tí rH rH 0 O rû >«-» O -rHq ^ 10 TJ 'tí O > «w O o 0 ^tí^ . > O'H r0> H ctf-H Jj 4-> IH <í • ^ S*Bg Tí 0 O 0 0 a g o "3 co S tí «H S Hg •V tí % öa •sfi w tí co tí CD - m -O tí 0 ty> tí tí o c3 33 0 3 tí o tí «H ° a s 5 a a (ü -tí 0 > 0) «s tí co 0) § > «M ft co ft ft o K Ü --tH í -is tí ^ w § >> ©a TS tJ> tí VwJ O JL| s S o s In view of the effectiveness of sodium arsenite when used in combination with a supplemental fertilizer, treatments,. employing five different rates of this material, were applied at bi-weekly intervals on a pitching green located at the Ranier Golf and Country Club in Seattle. These treatments, initiated in late summer of this year, should give a more comprehensive picture of the effectiveness of this material under actual golf-use conditions. Another herbicide, namely a sodium salt of 2,4-D, has also shown exceptional promise as a control of pearlwort. In a series of treatments conducted in 1952 at the Tacoma Golf and Country Club this material, when applied in a dry mix with an organic fertilizer, checked completely the growth of pearlwort. However, the dry or powder preparations of 2,4-D that were so very effective in these early tests are no longer available on the market. Recently, a small quantity of a similar 2,4-D material was obtained for experimental purposes. A series of test plots which will include the application of this material at several rates will be set out in 1954. The information that has been obtained thus far strongly recommends the use of sodium arsenite (1/2 oz. /1000 sq. ft.) applied in a dry mix with a supplemental fertilizer. The importance of the supplemental fertilizer cannot be over-emphasized. The desirable grasses in a golf green must be strengthened and invigorated to resist any new infestation of pearlwort and to crowd out existing clumps of this weed that have been weakened by the application of the herbicide. Sodium arsenite, when applied in dry form at regular two-week intervals, has weakened the pearlwort thereby contributing to its gradual disappearance without burning or otherwise disfiguring the green. -o- WATER MANAGEMENT CHARLES G. WILSON Western Director, USGA Green Section, Western Office, Davis, California My subject for today is Water Management, and certainly the Green Section feels that the use, or misuse, of water is the primary cause of most of our turf headaches. It influences the disease and weed symptoms that we see; it is tremendously important as far as plant food requirements and turf species are concerned; and in the case of surface feeding insects, our watering practices often nullify the results obtained from using good insecticides. And of course during critical hot spells it is usually water that is primarily responsible for the condition known as scald or melting out. In order to properly understand how to water it is necessary to understand some of the fundamentals facts of water management. To begin with, sprinklers do not apply moisture at the rate that the soil under our turf has the ability to absorb it. Most of the sprinklers in common use today apply water entirely too rapidly. Other fundamental facts relate to the nonuniformity of wetting of various soils because of ground contours that allow run-off; the management that we employ in building false water tables by applying alternate layers of sand, soil and peat astopdressing; ancbf course nature?s built-in headaches, which we call hard pan. Soils do not wet uniformly and this is known by everyone because of the condition known as localized drying or dry spots that appear on our turf areas. One reason for dry spots is an improper sprinkler distribution pattern. Although sprinkler design may look good on paper, wind movement can disrupt the distribution of the best designed sprinkler system. Compaction by foot, by caddy cart, and heavy machinery used in construction is responsible in many instances for localized drying and poor water infilitration. Root competition (both trees and shrubs) also is a cause of rapid drying out because of the competitive factor for moisture. With most of our turfgrasses we find that the build up of thatch or partially decomposed organic matter from stems, stolons, and clippings tend to shed water on the high spots, resulting in un~ uniform wetting. Another fundamental fact is that it is impossible to partially wet a soil. How often have you heard the statement that we could put on the water for one half hour tonight with the thought in mind that the entire soil profile would be uniformly wet. Of course this cannot happen because the surface or any type soil must reach its field capacitybefore percolation or gravitation will wet the lower depths. Another thing about wetting soils is that you can't tell if moisture is adequate or not by the feel of the turf underfoot. As an example, we have allowed a plot of grass to remove all the available moisture to a depth of two feet, and then watered a portion of the area to apply 2-inches of moisture, and another portion to apply 2-feetof water. Immediately after the sprinklers are turned off the feel underfoot is exactly the same. You need a soil sampling probe to ascertain how much water is needed. In California a few golf and lawn supply dealers are handling these 18 to 20 inch soil sampling probes. We feel that the intelligent irrigator needs such a tool. What exactly do we mean by under and over watering? The fundamental rule is this: when more water is applied than is necessary to wet the soil in the effective zone of rooting, you are definitely overwatering, regardless of soil type. How often have you heard the erroneous statement that you can!t overwater a sandy soil? The thought in mind probably being that since a sandy soil is well drained you never notice any puddling on the surface. This does not mean however that you can't over water a well drained sandy porous soil. The fact is that by allowing sprinklers to run on such a soil for long periods of time you not only waste water, but in addition you leach out valuable plant food nutrients, thus increasing your fertilizer as well as your water bill. Actually it is often the heavy soils that are notoriously underwatered rather than overwatered. I know this statement may sound strange to some of you. However, it is fairly obvious in that a heavy soil (clay) takes a great deal more water in the form of surface inches of rainfall or irrigation to wet the soil to a given depth when compared to a sandy soil. Most turf areas are both under and over watered, and this can happen within a relatively small area, such as on a putting green. We find that a proper setting for a green that is open and high on a windy hill is usually entirely too much for a pocketed green. This is influenced of course by air movement which in turn influences your evaporation rate. Competition from tree roots, temperature, and humidity also are factors that make it impossible to use the same sprinkler setting on each green. Sprinkler settings that adequately water the high spots on any given putting green or turf area invariably apply too much water to the low areas. Actually, we like to see localized dry spots on collars and backs because it indicates that at least excess water is not being applied in the low spots. Soils should dry from the top down, not from the bottom up. When sub-soil capable of encouraging grass roots is overly wet you are overwatering. When it is dry you are underwatering. What are the rooting capabilities of some of our major turf grasses ? For this information you are referred to Dr. R. M. Hagan's article on "Know How to Water", which appeared in the February 1953 issue of our USGA JOURNAL AND TURF MANAGEMENT. You will note that the creeping red fescues have effective roots approximately 2-inches deeper than did the Chewings fescue. Highland bent was a little bit better than the fescues. Kentucky bluegrass almost doubled the amount of effective roots by penetrating to the 30-inch level. Merion bluegrass was even better than common Kentucky bluegrass. Our tall fescues, such as Kentucky 31 (Alta is another example) have root systems at a depth of better than 36 - inches. Bermuda, both the improved U-3 and the common strain, have effective root systems to a great deal more than 36-inches. In this study considerable moisture extraction took place below the depths you actually see on the chart. As an example roots were found below the 5-foot depth on Merion bluegrass, and considerably below 6-feet on bermudagrasses. Another chart in this article shows the elapsed days before distinct wilting took place. With the creeping fescues and bents, the grasses went 14 days without any loss of color. It took this long before wilting or tracking occurred. Kentucky bluegrass went 24 days between irrigations. Merion bluegrass 3G days, and the Kentucky 31 fescue approximately 36 days. You will note that bermuda is not listed. Ilis the most drought tolerant of all grasses tested, and the reason it hasn't been listed is that it was watered one time, by accident, in 1952. We do not know how long it would have gone before wilting took place. During 1953 it was never watered, and Davis was both hot and dry with a water use rate that closely approached 2-inches per week. Better than 130 days elapsed between rains. We were dissatisfied with the performance of red fescue because we know it to be one of our most drought tolerant grasses in the Northwest and also in part of the East. We think therefore, that this same experiment might well be repeated here in the Northwest, in the event that some other factor, for instance heat, may have influenced the depth of rooting of our red fescues. Possibly the most outstanding finding of all is the importance of uniformity of soil toa tremendous depth. In other words, no false water tables by adding sand and then peat and then goingback to soil again, because such layers will interfere with maximum depth of rooting. How then should we water ? Well, certainly we can say that insofar as our turf use will allow, itshouldbe infrequently and deeply. The schedule of course is going to depend upon soil texture, water use rate in your area, effective depth of rooting, and the delivery rate of your sprinkler. Delivery rate can be easily ascertained by using coffee cans as rain gauges. These can be spaced from the sprinkler setting to the outer perimeter and will tell you in short order how much water your sprinkler is delivering. It should be appreciated that we loose pressure and increase frictional losses as we get farther away from the pump. Therefore, the same type sprinkler may be delivering a different amount of water in two different areas. Soil texture is a known fact and y our county agent or agricultural experiment station can tell you whether or not you have a sand or a loam or clay. We also know that we can grow grass onanytype of soil as long as it is uniform. In fact many of our turf headaches result from improper mixing of soil materials during construction. We find that the use of a Rototiller often floats the fines to the top which results in layering, and use of disc often leaves pockets of one material or another where turns are made. For this reason the USGA Green Section advocates mixing soil materials off of the green site. The water use rate in your area, or the approximate rate at least, is probably available through your local experiment station or from your county agents office. Naturally it will differ with the season and from hour to hour during the day. It probably approaches 1-inch a week along the coast, and ease of the mountains possibly is 11/2 to 1 3/4 inches per week during the hot summer season. Water management is the most important influence on the effective depth of rooting. Deep roots are the best measure of turf quality that we have. Almost invariably good roots will mean good tops. How do we know what our depth of rooting is? Again I will repeat, you need some sort of a soil probe to find out. How J about a cup cutter change ? It works fine, except you never know on the high spots because cups are never set there. I can say that on tests I made on greens in the spring of this year, in both the Western and Eastern parts of Washington and Oregon we found many greens where roots were emerging from the bottom of our 18-inch soil probe. Another one of Dr. Hagan!s charts explains irrigation interval as influenced by soil texture and depth of root zone where the water use rate is 1-inchper week, oisimilarto the use rate in the Seattle, Portland area. This information tells us that with effective roots 24-inches deep the turf should go for at least 16 days between irrigations on aloam soil, 7 1/2 days on a sandy soil, and 27 days on a clay soil. Another chart tells us the amount of surface inches of water required to wet soils to given depths, assuming no surface run-off. From this chart we find that if you wish to wet a 12-inch depth of loam soil it is going to take approximately 11/2 inches of water to do it. With a sandy soil it will take about 3/4 inch and with a clay soil it will take about 2 1/2 inches of water to wet the soil to a 1-foot depth. This logically leads us to the next point concerning the sprinklers that are in use today. How long must they run on an average to deliver an inch of water? This varies with make and size, and as previously mentioned each superintendent should find out by using cans as rain gauges. If, as an example, it delivers 1/3inch per hour the sprinkler will have to run for 3 hours to apply 1-inch of water. On aloam soil it would have to run approximately 4 1/2 hours to wet the soil to a depth of one foot, assuming that the grass had removed all available moisture to this depth. Thus it is very very hard to water properly, because when we water infrequently our sprinklers have to set for long periods to put on enough water, and even so they apply moisture too rapidly. On many areas we can't allow sprinklers to run for long periods of time without getting excessive run-off. Therefore, we must resort to maximum settings before run-off occurs. The intelligent irrigator picks up during the day by hand, with soakers, with sub root irrigators, or in some instances the use of plastic perforated hose that will apply moisture slowly. Dry spots can be identified on bentgrass before wilting tskes place by the lack of dew or guttational water on the tips of the blades in early morning. We can use aeration tools to increase water infiltration and thus hold the moisture on the slopes without getting excessive run-off. We can resort to root pruning with a tree root pruner or edging our turf areas to prevent competition from tree and shrub roots robbing our turf grasses of moisture. Inclosing, I will again point out that you can't water properly on a fixed schedule. Most of us do water on a fixed schedule. If soil sampling probes show that moisture is adequate, v/e think it advisable for each turf manager to let the night water men sweep out the barn or tool shed on occasion, ancbetter turf will be the result. - o - PHYSICAL PROPERTIES OF SOILS WITH SPECIAL REFERENCE TO WATER MANAGEMENT WALTER H. GARDNER Pullman, Washington SOIL PHYSICAL CONDITION AND PLANT GROWTH The factors which are important to plant growth and which depend largely on soil physical conditions are: aeration water supply soil temperature mechanical impedence to roots and shoots These factors depend upon the nature of the mineral and organic constituents of the soil and upon the geometry or physical arrangement of the primary soil particles. The sizes and size distribution of primary soil particles are discussed using the terms "soil texture" and "soil textural c l a s s S o i l particles whose diameter is less than 0.002 mm. are classed as clay, those particles greater, than 0.002 mm. but less than 0. 05 mm. are classed as silt, particles greater than 2 mm. are classed as gravel. Depending upon the relative quantities of sand, silt or clay contained in the soil various textural class names are used to describe a soil. These are indicated in the textural triangle of Figure 1. The physical arrangement of primary particles into coherent groups and the arrangement of primary particles and coherent groups in the bulk soil is thought of as soil structure. The coherent groups are called aggregates and the stability of these coherent groups against various destructive forces is called aggregate stability. A common measure of aggregate stability calls for subjecting a soil sample to an arbitrary disruptive force (commonly moving water) and then measuring the size and size distribution of the aggregates which remain unbroken after the soil has been subjected to this disruptive force for a suitable interval of time. In discussing aggregate stability one must always specify the nature of the disruptive force against which the aggregates are stable. About 35 per cent of the soil volume of ordinary agricultural soils is occupied by soil particles with the remaining voids being occupied by air and water. The total volume of soil voids and the dimensions and shape of the void spaces depends upon both the textural class of the soil and the structure of the soil. Fig. 1. S O I L T E X T U R A L TRIANGLE Water retention and transmission in the soil depends largely upon the geometry and size of the void spaces. The quantity of air in a soil is inversely proportional to the water content. Aeration and water supply then, depend upon soil texture and soil structure. The temperature of the soil depends largely upon the net amount of solar radiation absorbed (the difference between that absorbed and that re-radiated), the heat capacity and heat conductivity of the soil-water system and upon conduction losses at the soil surface. Temperatures are also influenced by heat gains and losses from condensation and evaporation of water and through heat of wetting. Biological activity may also have a significant effect on soil temperature under certain conditions. Wetsoils in general have a higher heat capacity than dry soils because of the high specific heat of water compared to the grass heat capacity of the dry soil-plus-air system. Likewise a wet soil transmits heat more readily than a dry one. Because they have a high heat capacity and good conductivity soils that are poorly drained are generally slower to warm up in the spring than are the well drained, dryer soils. Favorable soil temperature is important to plant growth so that properties of soils which influence soil temperature also indirectly influence plant growth. Although plant roots are known to exert tremendous forces and can break rocks under some circumstances, for optimun growth the soil should not offer great mechanical resistance to the penetration of roots and the emergence of shoots. Soils having a small amount of void space and soils which form hard crusts are not ideal for best plant growth. The resistance to root penetration and the emergence of seedlings generally increases as soils dry out. Voids should represent 50to 60 per cent of the soil volume and a soil should be somewhat loose and pulverent for optimum plant growth. PRINCIPLES OF WATER RETENTION AND MOVEMENT IN THE SOIL In order to under stand problems of water management it is necessary to understand something about the forces involved in water movement and retention in the soil. Moisture present in the soils which are supporting plant-growth exists under negative pressure. For convenience negative pressure is called tension. To illustrate more clearly the meaning of tensions and pressures in the soil consider a rain drop and water in the space between two spheres placed close to each other but not quite touching (fig. 2). RAIN DROP WATER B E T W E E N SPHERES WATER INCAPILLARY « TUBE Pá" \ / P2