Tifway Bermudagrass Response To Potassium Fertilization

Transcription

1 Tifway Bermudagrass Response To Potassium Fertilization J. B. Sartain* ABSTRACT cold-hardiness (Beard, 1982). Gilbert and Davis (1971) Potassium fertilization rates used for Tifway bermudagrass [Cynogrowth of Tifdwarf and Tifgreen bermudagrasses reported that a 4N:6K ratio provided excellent shoot don dactylon (L.) Pers. C. transvaalensis Burtt-Davy] vary greatly among turfgrass managers and there is no consensus as to the actual following cold treatment, although shoot growth at quantity required or as to the best Potassium (K) source to use. Effects the 4N:6K ratio was not statistically better than a 4N:3K of K source and rate on Tifway bermudagrass shoot and root growth, or 2N:1K ratio fertilizers. Peacock et al., (1997) requality and tissue K concentration were studied in a 3-yr field study ported no improvement in turf quality, color, rooting, in Central Florida. Turf was grown on an Arredondo fine sand (loamy, or cold tolerance of Tifgreen bermudagrass as a result siliceous, hyperthermic, Grossarenic Paleudult). Two K sources (KCl of increasing rates of K. Snyder and Cisar (2000) found and K 2 SO 4 ) were applied at 8 rates (0, 3.7, 7.4, 9.8, 14.7, 22, 29.4, and 36.8 g K m that increasing K beyond a N:K fertilization ratio of 2: d 1 ) in conjunction with N applied monthly at 4.9 g m had no effect on Tifgreen bermudagrass appearance, 2. Potassium chloride produced a more rapid shoot growth than did K 2 SO 4, but this effect may be linked to the N source. Bermudagrass growth, root weight, or resistance to bermudagrass deshoot growth rate and tissue K concentrations were increased by K cline [Gaeumannomyces graminis (Sacc.) Arx. & D. Oli- fertilization up to 7.4 g K m 2 90 d 1. There was no additional increases ver var. graminis]. Increasing K relative to N did not in either of the aforementioned parameters, regardless of the K level result in commensurate increases in tissue K. Carrow applied. Turfgrass quality and root weight were not influenced by K et al. (1987) found somewhat less dollar spot (Sclerotinia application. Greater root weight was observed during May, June, and homoeocarpa F.T. Bennett) in Tifway bermudagrass July than August, September, and October. Observed turfgrass growth treated with 4.9 gkm 2, when compared with 9.8 and responses to Mehlich-1 extractable K levels suggest that 30 mg K kg g K m 2. Johnson et al. (1987) observed no benefit soil may be adequate for optimum growth. For an N application rate of 4.9 g m in reducing dollar spot in Tifway from 0.5 to 30 g K m 2. 2 mo 1, K fertilization levels above 9.8 g K m 2 90 d 1 probably will not enhance Tifway bermudagrass shoot and root growth, Decreases in winter injury or increases in bermudagrass quality, or tissue K concentration. winter hardiness due to increased K levels have been reported (Juska and Murray, 1974). Beard and Rieke (1966) stated that turfgrass winter survival was maximal Nitrogen (N) requirements for growth of Tifway when K rates were about one-half the N rate. Total bermudagrass have been well established. To nonstructural carbohydrates (TNC) decreased in roots maintain good quality of Tifway bermudagrass, at least and rhizomes of Tifdwarf and Tifway hybrid bermu- 20 to 30 g N m 2 yr 1 were required in Georgia (Carrow dagrasses with increasing rates of K, but had no effect et al., 1987). Additionally, Callahan and Overton (1978) on shoot and stolon TNC concentrations (Miller and reported a significant increase in Common bermu- Dickens, 1996). dagrass density when N was increased from 10 to 20 g Numerous K sources are available and turfgrass re- m 2 y 1 in Tennessee, but the turfgrass did not respond sponse to different K sources have been evaluated. Horn as readily to potassium (K) as to N. Previous studies (1965) reported that K 2 SO 4 and K 2 CO 3 induced superior have shown that Tifway bermudagrass either does not Tifway bermudagrass quality relative to other K sources. respond positively to K (Barrios and Jones, 1980) or However, when the plots were fertilized with ammo- only responded to low rates of less than 4.9 (Carrow et nium sulfate, the quality differences attributed to the K al., 1987) or 12.5 g K m 2 (Horn, 1969). When clippings sources subsided. Snyder and Cisar (1990) found no were returned, Tifway bermudagrass growth rate did bermudagrass growth response to various K sources. not respond to K (Sartain, 1993). Potassium sulfate leaches less rapidly than potassium Typically, turfgrasses accumulate about twice as much chloride, so a greater utilization efficiency of potassium N as K so these elements are recommended to be ap- sulfate is anticipated (Chung et al., 1998). plied at a 2:1 (N:K) ratio (Turgeon, 1985). Augustin Wide ranges in tissue K concentrations have been (1992) reported that turfgrass managers use relatively reported and reflect differences in turfgrass species large amounts of K fertilizer, generally at levels equal (Mehall et al., 1983; Turner and Waddington, 1983), to or exceeding the rate of N. Use of high K rates may fertilization practices (Sartain and Dudeck, 1980; Sny- have been prompted by reports that K improved disease der and Cisar, 2000), and time of sampling (Mehall et resistance, and drought, heat and wear tolerance (Turof tissue K levels difficult for purposes of diagnosing al., 1983). These wide differences make interpretation ner and Hummel, 1992) and enhanced root growth and deficiencies. However, recent findings by Snyder and Cisar (2000) for Tifgreen bermudagrass suggest a rela- Soil and Water Science Dep., Univ. of Florida, P.O. Box , tionship between tissue K and growth response. When Gainesville, FL This research was supported by the Florida Agricultural Experiment Station, and approved for publication as Journal Series No. R Received 24 Apr *Corresponding Abbreviations: K, potassium; N, nitrogen; KCl, potassium chloride; author (jbs@gnv.ifas.ufl.edu). K 2 SO 4, potassium sulfate; (NH 4 ) 2 SO 4, ammonium sulfate; NH 4 NO 3, ammonium nitrate; TNC, total nonstructural carbohydrates; CEC, Published in Crop Sci. 42: (2002). cation exchange capacity. 507

2 508 CROP SCIENCE, VOL. 42, MARCH APRIL 2002 Table 1. Effect of potassium source on yearly mean Tifway ber- mudagrass shoot growth rate. the tissue K level was below 13 gkkg 1 dry matter, a growth response to K application was obtained. Once tissue K levels reached approximately 16 g K kg 1 dry matter, no increase in tissue K concentration or growth KCl K 2 SO 4 KCl K 2 SO 4 KCl K 2 SO 4 rate were observed in response to the application of gm 2 d additional K Arredondo fine sand is composed of 960g kg 1 sand Contrasts ** *** * and has a cation exchange capacity (CEC) of 7.7 cmol 3 Collections 12 Collections 4 Collections n 72 n 288 n 96 ( ) kg 1 (Carlisle et al., 1989), thus the potential for K CV 19.3% CV 19.5% CV 15.9% leaching is great. Sartain (1995) reported significant K Single degree of freedom contrasts were generated using SAS GLM Proc. leaching from this soil. Unfertilized Arredondo fine * Indicates significance at P sand typically contains very low Mehlich-1 extractable ** Indicates significance at P K levels (Sartain, 1993). *** Indicates significance at P Although the effects of K on turfgrasses has been studied for decades, there is no consensus among turf- ples were collected from each plot with a 1.25 (length) by 10 (width) by 15 (depth) cm flat root sampler for root growth grass managers as to the proper K fertilization program. estimates. In 1996 and 1997, root samples were collected in This research was undertaken to evaluate the influence June. Root samples were collected every 14 d over a 180 d of K fertilization rate and source on Tifway bermu- period, for a total of 13 times in Roots were washed dagrass shoot growth rate, root density, visual quality, free of soil, oven dried at 65 C for 24 h and weighed. At the and tissue K concentration. end of each growth year, soil samples were taken (0 to 10 cm deep) from each plot and analyzed for ph (1 soil:2 water), and Mehlich-1 (0.05 M HCl in M H 2 SO 4 ) extractable MATERIALS AND METHODS P, K, Ca, and Mg. Visual quality ratings, based on a 1 to 9 A 3-yr field study was initiated at the G.C. Horn Turfgrass scale, were taken twice monthly each year. A quality rating Field Research Laboratory, Gainesville, FL, during May 1996 of 9 represented superior quality turf, 5.5 the minimally on an established stand of Tifway bermudagrass growing on acceptable turf, and 1 dead or brown turf. a Arredondo fine sand (ph 6.6). Mehlich-1 extractable K prior An analysis of variance was preformed on individual clipto treatment application was 17 mg K kg 1. Treatments were ping collections and on yearly composites. Data were analyzed applied to 2 by 3 m plots arranged in a randomized complete as a split-plot design with Statistical Analysis System (SAS) block split-plot design with three replications. Two K sources software, procedure PROC ANOVA (SAS Institute, Inc., (KCl and K 2 SO 4 ) were applied at 8 rates (0, 3.7, 7.4, 9.8, 14.7, 1985). Separation of means was accomplished with the general 22, 29.4, and 36.8 g K m 2 90 d 1 ). Since only one 90 d cycle linear model procedure (PROC GLM) and single degree of was evaluated in 1996, K and N were applied one and three freedom contrasts at P Since this study involved the times per year, respectively. In 1997 and 1998, two 90 d growth use of K rates and one of the objectives was to determine the cycles were evaluated, thus K and N were applied two and rate at which no additional response to applied K was obsix times per year, respectively. Nitrogen was applied at 4.9 tained, single degree of freedom contrasts were generated gm 2 30 d 1 with either (NH 4 ) 2 SO 4 or NH 4 NO 3. To balance with the general linear model procedure. In each contrast, the the quantity of S applied, NH 4 NO 3 was used on the K 2 SO 4 plots response variable at a K rate was compared with the average and (NH 4 ) 2 SO 4 was used in the KCl plots. The Arredondo effect of response at K rates greater in value, which was refine sand is a phosphatic soil which tests high in Mehlich-1 ferred to as rest in the figures. The K rate being compared extractable P (204 mg kg 1 ): Therefore, no P was applied. with the remaining larger rates was assigned a positive value Nitrogen and K sources were applied by hand. Approximately and the higher K rates were assigned a proportional negative 1 cm of irrigation water were applied following each N and value such that the sum of the weighted contrast values was K fertilization, and irrigation was provided throughout the zero. study to maintain adequate soil moisture based on the monthly average evapotranspiration. During the 90 d study period of 1996, and the 180 d periods of 1997 and 1998, 42.8, 83.0, and RESULTS AND DISCUSSION 83.7 cm of rainfall occurred, respectively. In addition, 55.5, Shoot Growth Rate 96.0, and 99.8 cm of water were applied by overhead irrigation in 1996, 1997, and 1998, respectively. The area was mowed to Shoot growth rate varied with K source and year a height of 1.3-cm twice a week. The number of days elapsed (Table 1). Yearly differences in growth rate most likely since the last mowing was used to calculate the turfgrass were influenced by proximity of the clipping collection growth rate. Clippings were returned, except when collections date to the N application date. Shoot growth rates were were made for growth and tissue analysis. greater in 1998 than in 1996 because only 15 d elapsed During the first year of the study, one 90 d growth cycle following N application in 1998, whereas 30 d elapsed was investigated and clippings were collected three times at in In each of the 3 yr, KCl treated bermudagrass 30 d intervals for growth rate and K uptake estimates. Two, produced greater growth rates than turf fertilized with 90 d growth cycles were studied during the second and third K 2 SO 4. The K source effect may have been an artifact years. Clippings were collected twice monthly for a total of of the experimental design in that (NH 4 ) 2 SO 4 was ap- 12 times during the second yr and four times 45 d apart during the third year. Clippings were oven dried at 65 C for 48 h, plied to the KCl plots in order to balance the quantity weighed, ground in a stainless steel mill and ashed for 8 h in of S applied to all plots. In previous studies, (NH 4 ) 2 SO 4 a 450 C muffle furnace for K analysis. Total tissue K was produced a more rapidly growing Tifdwarf bermu- determined by atomic absorption spectrometry (Varian Spectr dagrass than NH 4 NO 3 (Horn, 1965; Volk, 1972). AA-20 Plus, Mulgrave, Victoria, Australia). Three soil sam- Quantity of applied K influenced Tifway bermu-

3 SARTAIN: TIFWAY BERMUDAGRASS RESPONSE TO POTASSIUM FERTILIZATION 509 Fig. 1. Effect of K application on growth rate of Tifway bermudagrass during 1997 and Single degree of freedom contrasts were generated with the SAS GLM Proc. *, *** at P 0.05 and P and nonsignficant (NS) at P Rest refers to the average of treatment means larger in magnitude than the one in the contrast. dagrass shoot growth rate in all 3 yr, but only data for not enhance shoot growth or K uptake. Apparently, 1997 and 1998 are presented (Fig. 1). Data for 1996 were Tifway bermudagrass does not exhibit luxury consumpomitted because they represent limited observations tion of K and high K:N ratios were not beneficial. Snyder and because turfgrass shoot growth rate was low due and Cisar (2000) reported maximum tissue K levels to the sampling sequence used. Single degree of freedom in Tifgreen bermudagrass in response to K application contrasts of shoot growth rate versus rate of K applied of 1.25 g m 2 30 d 1, with no additional tissue K increases revealed differences in growth rate up to approximately with increasing rates of K. 9.8gKm 2 90 d 1. Application of additional K beyond 9.8 g K m 2 90 d 1 did not increase shoot growth rate. Root Growth A total of 14.7 gnm 2 90 d 1 was applied, and this equates to an N:K application ratio of 1.5:1, which may A total of 1872 samples were taken during 1998 for be different from the N:K ratio being used by some root growth estimates. Potassium rate did not signifiturfgrass managers. Snyder and Cisar (2000) reported cantly influence root dry weight (Fig. 3). A June sam- a similar response to N:K fertilization ratio on Tifgreen pling in 1996 and 1997 revealed no K effect on root bermudagrass growing in a Hallandale fine sand (silifor application of elevated levels of K relative to N growth (data not shown). One reason typically given ceous, hyperthermic Lithic Psammaquent) in South Florida. is enhanced root growth. Beard (1973) suggested that turfgrass root growth was enhanced by K fertilization. Snyder and Cisar (2000) and Peacock et al. (1997) did Shoot Tissue K not show increased root growth of Tifgreen bermudagrass Tifway tissue K concentrations varied with K rate by increasing the K:N ratio. Trenholm et. al. and year (Fig. 2). Greater tissue K concentrations were (1998) reported a slight decrease in root growth of FloraDwarf observed during 1997 than 1998, possibly because the bermudagrass in response to K under long day greater growth rate in 1998 caused a dilution effect. In ( 13 h) conditions and increased Tifdwarf root growth both years, a maximum tissue K level was achieved (16 under short day ( 13 h) conditions. The findings pre- and 14 g kg 1 in 1997 and 1998, respectively) in response sented in this study suggest that there is limited influence to K applied at 9.8 g m 2 90 d 1. Greater applied K of applied K on Tifway bermudagrass root growth, even rates did not further increase tissue K. Maximum tissue when the turfgrass is growing in a sandy soil with limited K concentration was achieved in response to the application CEC and an inability to retain K against leaching losses. of 9.8 gkm 2 90 d 1 in both 1997 and Maxi- Time of year influenced root growth (Fig. 4). Maxi- mum shoot growth rate was achieved at 9.8 g K m 2 90 mum root weight was observed during May and was d 1, suggesting that the application of additional K does lowest during September. In general, the greatest root

4 510 CROP SCIENCE, VOL. 42, MARCH APRIL 2002 Fig. 2. Effect of K application on Tifway bermudagrass tissue K concentration during 1997 and Single degree of freedom contrasts were generated with SAS GLM Proc. *** and nonsignificant (NS) at P 0.01 and P 0.05, respectively. Rest refers to the average of treatment means larger in magnitude than the one in the contrast. weight was observed during the months of May, June, and July, and the lowest root weights occurred during August, September, and October. This reduction in root growth could have been related to a day length phenom- enon. Trenholm et al. (1998) reported a 13% reduction in Tifdwarf bermudagrass root growth when the day length was reduced to 13 h d 1. A reduction of approximately 16% in Tifway bermudagrass root growth was Fig. 3. Effect of K application on Tifway bermudagrass root dry weight during Single degree of freedom contrasts were generated with SAS GLM Proc. Nonsignifant (NS) at P Rest refers to the average of treatment means larger in magnitude than the one in the contrast.

5 SARTAIN: TIFWAY BERMUDAGRASS RESPONSE TO POTASSIUM FERTILIZATION 511 Fig. 4. Effects of sampling month on Tifway bermudagrass root dry weight in Single degree of freedom contrasts were generated with SAS GLM Proc. *** at P 0.01 and nonsignificant (NS) at P observed during the months of August, September, and K application. However, Carrow et al. (1987) reported October relative to that of longer day length periods in somewhat less dollar spot in Tifway fertilized with 4.9 May, June and July. g K m 2, but not at greater K rates. Johnson et al. (1987) found no benefit in reducing dollar spot on Tifway from Quality Ratings using 5.0 to 30 gkm 2. Incidence of disease in the current study was minimal; therefore, the influence of Quality ratings were not influenced by K in any year. increasing K rates on disease could not be effectively de- Turfgrass quality remained high through out the study termined. period. Mean quality ratings ranged from 6.7 to 6.9 with a coefficient of variability (CV) of 15.7%, 6.9 to 7.2 with Soil Analysis a CV of 11.9%, and 7.0 to 7.4 with a CV of 12.9% in 1996, 1997, and 1998, respectively. Somewhat lower Soil ph and Mehlich-1 extractable nutrient levels ratings were recorded early in the growing seasons, but prior to treatment application were within the optimum at no time was there an improvement in visual quality range for bermudagrass growth (Hanlon et al. 1990), related to K application. Growth rate was increased by except for K (Table 2). Based on current soil test inter- K application, but the response did not translate into a pretations, Mehlich-1 extractable K levels were very visual improvement in quality. Peacock et al. (1997) also low and a response to K fertilization would be expected did not observe an improvement in Tifgreen quality in at least 75% of the time (Hanlon et al. 1990). Mehlich-1 response to K application. Snyder and Cisar (2000), extractable P and Mg were very high, and were not however, reported an improvement in turfgrass quality applied during the study. Adequate levels of micronutri- in response to K, which mainly was due to the poor ents were present and also were not applied. performance of Tifgreen bermudagrass on plots receivgrowth season and in response to K application (Table Mehlich-1 extractable K increased during the 1998 ing no K. The lack of a response to K on Tifway quality may be related to the return of clippings. Clippings were 3). By the end of the growing season, soil samples from returned in this study, but were removed by Snyder and Cisar (2000). In a previous study on Tifway, a growth Table 2. Soil chemical properties prior to treatment application. and quality response to K was observed on plots where Mehlich-1 extractable clippings were removed (Sartain, 1993). The influence ph P K Ca Mg Fe Mn Cu Zn of K on bermudagrass quality has most often been remg ported as an indirect effect on disease. Horn (1970) kg 1 reported reduced dollar spot incidence in response to

6 512 CROP SCIENCE, VOL. 42, MARCH APRIL 2002 Beard, J.B., and P.E. Rieke The influence of nitrogen, potassium, Table 3. Mehlich-1 soil extractable levels of selected nutrients as and cutting height on the low temperature survival of grasses. influenced by potassium applications during the 1998 bermu- p. 34. In Agronomy Abstracts. ASA, Madison, WI. dagrass shoot growth period. Callahan, L.M., and J.R. Overton Effects of lawn management practices in a bermudagrass turf. Tenn. Farm Home Sci. 108: K-rate Begin-season Mid-season End-season Carlisle, V.W., F. Sodek, III, M.E. Collins, L.C. Hammond, and W.G. (2 May 1998) (29 July 1998) (27 Oct. 1998) Harris Characterization data for selected Florida soils. Soil gm 2 90 d 1 mg kg 1 Sci. Res. Rep. 89 1, Univ. of Florida., Gaineville, FL Carrow, R.N., B.J. Johnson, and R.E. Burns Thatch and quality of Tifway bermudagrass turf in relation to fertility and cultivation Agron. J. 79: Chung, K.-Y., J.B. Sartain, and E.W. Hopwood Leaching char acteristics and nutrient supplying potentials of selected P and K fertilizer sources. Soil Crop Sci. Soc. Florida Proc. 58: Gilbert, W.B., and D.L. Davis Influence of fertility ratios on winter hardiness of bermudagrass. Agron. J. 63: Potassium (K) was applied twice at the above rates on 2 May 1998 and Hanlon, E.A., G. Kidder, and B.L. McNeal Soil, container 29 July media, and water testing. Cir Florida Coop. Ext. Service, Univ. of Florida, Gainesville, FL. Horn, G.C The effects of potash sources at different rates plots receiving 9.8 to 22.0 gkm 2 tested medium in on the response of Tifway bermudagrass. Proc. Florida Turfgrass Mehlich-1 extractable K, and a response to K addition Mgmt. Conf. 13: would be expected 25% of the time (Hanlon et al. 1990) Horn, G.C Potassium fertilizers for Tifway bermudagrass. p. No growth or tissue K response was observed when the In J.R. Escritt (ed.) Proc. 1st Int. Turfgrass Res. Conf., Sports Turf Research Institute, Bingley, England. application of K was 9.8 gkm 2 or greater (Fig. 1 and Johnson, B.J., R.N. Carrow, and R.E. Burns Bermudagrass turf 2) and the Mehlich-1 extractable K level were 31 to 47 response to mowing practices and fertilizer. Agron. J. 79: mg kg 1 soil. These findings suggest that the current Juska, F.V., and J.M. Murray Performance of bermudagrass in interpretation of Mehlich-1 soil test results for bermu- the transition zone as affected by potassium and nitrogen. p In E.C. Roberts (ed.) Proc 2nd Int. Turfgrass Res. Conf., dagrass may not be correct, and that the sufficient Meh- Blacksburg, VA June ASA and CSSA, Madison, WI. lich-1 extractable K level should be adjusted downward Mehall, B.J., R.J.Hull, and C.R. Skogley Cultivar variation in to possibly as low as 30 mg K kg 1 soil. Kentucky bluegrass: P and K nutritional factors. Agron. J. 75: CONCLUSIONS Miller, G.L., and R. Dickens Bermudagrass carbohydrate levels as influenced by potassium fertilization and cultivar. Crop Sci. When a critical minimum K tissue concentration was 36: Peacock, C.H., A.H. Bruneau, and J.M. Dipaola Response of achieved, approximately 1.5 mg kg 1 tissue, additional the Cynodon cultivar Tifgreen to potassium fertilization. Intl. Turf K does not result in additional K uptake, shoot growth, Soc. Res. J. 8: Sartain, J.B Interrelationships among turfgrasses, clipping recyor improved visual quality or root growth in Tifway cling, thatch, and applied calcium, magnesium and potassium. bermudagrass. Monthly variations in root dry weight Agron. J. 85: were observed, but application of K did not result in Sartain, J.B Leaching potential of potassium fertilizer sources. additional root growth. The critical Mehlich-1 extractof Florida, Gainesville, FL. p In J.L. Cisar (ed.) Turfgrass Research in Florida. Univ. able level of soil K appeared to be near 30 mg K kg 1 Sartain, J.B., and A.E. Dudeck Yield and nutrient accumulation soil. Information collected through this 3 yr study sug- of Tifway bermudagrass and overseeded ryegrass as influenced by gested that K rates in excess of 0.50 to 0.67 times that applied nutrients. Agron. J. 74: of N application rates (4.9 g N m 2 30 d 1 ) do not result Snyder, G.H., and J.L. Cisar Evaluation of controlled-release potassium fertilizers for turfgrasses. p In T.E. Freeman (ed.) in additional tissue K uptake, shoot and root growth Turfgrass Research in Florida. Univ. of Florida, Gainesville, FL. or enhanced visual quality. Additional research with Snyder, G.H., and J.L. Cisar Nitrogen/potassium fertilization intensive soil sampling and measurement of correspond- ratios for bermudagrass turf. Crop Sci. 40: ing turfgrass tissue K levels should be performed prior Statistical Analysis System Institute Inc SAS/STAT Guide for to establishing new interpretations relative to the critical personal computers. Version 6 Edition. Cary, NC. Trenholm, L.E., A.E. Dudeck, J.B. Sartain, and J.L. Cisar Mehlich-1 extractable level of soil K. Bermudagrass growth, total nonstructural carbohydrate concentration, and quality as influenced by nitrogen and potassium. Crop REFERENCES Sci. 38: Turgeon, A.J Turfgrass management. 4th ed. Prenice-Hall, Inc. Augustin, B.J Surviving drought. Grounds Maintenance 27(5): Upper Saddle River, NJ Turner, T.R., and N.W. Hummel, Jr Nutritional requirements Barrios, E.P., and L.G. Jones Some influence of potassium and fertilization. In D.V. Waddington et al. (ed.) Turfgrass. Agronnutrition on growth and quality of Tifgreen bermudagrass. J. Am. omy 32: Soc. Hortic. Sci. 105: Turner, T.R., and D.V. Waddington Soil test calibration for Beard, J.B Turf management for golf courses. Macmillian Pub- establishment of turfgrass monostands. Commun. Soil Sci. Plant lishing Co., NY. Anal. 9: Beard, J.B Turfgrass: Science and culture. Prentice-Hall, Englewood Cliffs, NJ. Volk, G.M Current research results on turf fertilization. Proc. Florida Turfgrass Mgmt. Conf. 20:94 98.