Progress 06/01/01 to 05/31/06
Outputs
This project was initiated in June 2001. Since its initiation several contributions have been made. The major thrust of the project was to reduce turfgrass water use and enhance drought avoidance mechanisms. Kentucky bluegrasses were evaluated for root production, depth and distribution under declining moisture. Turfgrass clipping yield, verdure, and top growth among cultivars were assessed. Georgetown produced the greatest root mass and Kenblue and NE-80-88 had the least. Total root production varied by 25% among cultivars tested. These results support the potential to select genotypes with improved root distribution and plasticity. Irrigation treatments based on 60, 80 and 100% potential evapotranspiration (ETp) and K nutrition at 0, 20, 40 and 60 g K m-2 season-1 were applied in two experiments to field-grown Kentucky bluegrass maintained under fairway conditions. Turfs were uniformly trafficked to provide added stress. Irrigation meters were used to monitor water
applications. Analysis of variance indicated significant interaction between irrigation and K nutrition treatments for soil and leaf tissue K content, load bearing capacity, and ball roll distance. There were no significant effects of irrigation or K treatments on turfgrass color or quality under the conditions of this investigation. Soil K levels ranged from 318 to 1064 mg K kg-1 for all treatments by the end of the growing season. Leaf K content varied from 1.67 to 2.57%. Ball roll distance was reduced by as much as 26% at 100% ETp and 60 g K m-2 season-1. Irrigation treatments of 60 and 80% ETp used 1225 m3 ha-1 (21%) and 2387 m3 ha-1 (40%) less water without a significant reduction in turfgrass quality. Results from this research support the potential to manipulate irrigation rate and K nutrition level to maintain desirable turfgrass quality and reduce water consumption under fairway management conditions.
Impacts
This research demonstrates the opportunity to select Kentucky bluegrass cultivars with enhanced rooting characteristics, and to manipulate irrigation and potassium nutrition to reduce turfgrass water use and conservation.
Publications
- Shearman, R.C., K.S. Erusha, and L.A. Wit. 2005. Irrigation and potassium effects on Poa pratensis L. fairway turf. International Turfgrass Soc. Res. J. 10:998-1004.
- Streich, A.M., R. E. Gaussoin, W.W. Stroup, and R. C. Shearman. 2005. Survey of management and environmental influences on golf ball roll distance. International Turfgrass Soc. Res. J. 10:446-454.
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Progress 10/01/03 to 09/30/04
Outputs
Interest in developing water conservation practices exists in the turfgrass industry today. This study was conducted near Mead, NE. It was initiated to evaluate irrigation and K nutrition treatment effects on a Kentucky bluegrass turf maintained under fairway conditions. The objectives of the study were to: 1) Determine irrigation and K nutrition treatment effects on turfgrass quality; 2) Assess irrigation and K nutrition effects on soil and leaf tissue K content; and 3) Determine the effects of irrigation replacement on potential water conservation. Irrigation treatments based on 60, 80 and 100% potential evapotranspiration (ETp) and K nutrition at 0, 20, 40 and 60 g K m-2 season-1 were applied in two experiments to field-grown Kentucky bluegrass. Turfs were uniformly trafficked to provide added stress. Irrigation meters were used to monitor water applications. Analysis of variance indicated significant interaction between irrigation and K nutrition treatments for
soil and leaf tissue K content, load bearing capacity, and ball roll distance. There were no effects of irrigation or K treatments on turfgrass color or quality. Soil K levels ranged from 318 to 1064 mg K kg-1 by the end of the growing season. Leaf K content varied from 1.67 to 2.57%. Ball roll distance was reduced by as much as 26% at 100% ETp and 60 g K m-2 season-1. Irrigation treatments of 60 and 80% ETp used 1225 m3 ha-1 (21%) and 2387 m3 ha-1 (40%) less water without a reduction in turfgrass quality. Results from this research support the potential to manipulate irrigation and K nutrition level to maintain desirable turfgrass quality and conserve water. Buffalograss use as a turf in Northern climates is limited by its winter dormancy. A buffalograss mixed with cool-season turfgrasses might extend the green appearance and enhance quality. Research was conducted to determine the effects of overseeding fine-leaved fescue in buffalograss turf on turfgrass color and quality, and
species, seeding rate and date, and core cultivation effects on hard fescue, blue fescue, and Chewings fescue establishment in buffalograss turf. Fescues were seeded at 10, 20 and 30 g mP-2, seeding dates (fall, spring or split fall-spring), and core cultivation (single or double pass) were evaluated for species composition, turfgrass quality, color and green cover. Buffalograss turf overseeded with blue fescue in fall had the highest turfgrass quality, color and green cover ratings. Fall overseeding resulted in the highest shoot density values. Spring overseedings were below acceptable levels. Seeding rate effect was linear with each increment between 10 g m-2 and 30 g m-2 increasing fine-leaved fescue shoot density, turfgrass quality, color and green cover. Blue fescue-buffalograss mixtures overseeded in the fall exhibited 80% green cover, when buffalograss was dormant. Turfgrass green cover in the mixture was extended by 2 months compared to buffalograss monostands growing in
adjacent areas. The results of this study support the use of fine-leaved fescue and buffalograss mixtures to extend turfgrass green appearance and enhance quality.
Impacts
Drought stress and water conservation are critical issues that the turfgrass industry must face. This research offers management options with potassium nutrition and irrigation frequency that conserve water without loss of turfgrass quality. Acceptance of warm season turfgrass is in northern climates is limited by their winter dormancy. This reasearch demonstrates the benefits of mixing buffalograss and fine leaf fescues to extend green color and enhance turfgrass performance.
Publications
- Severmutlu, S., T.P. Riordan, R.C. Shearman, R.E. Gaussoin and L.E. Moser. 2005. Overseeding buffalograss turf with fine-leaved fescues. Crop Science. (In Press).
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Progress 10/01/02 to 09/30/03
Outputs
Considerable interest in developing water conservation practices exists in the turfgrass industry today. However, water conservation that results in a loss of turfgrass quality is not acceptable in most cases. This investigation was conducted at the John Seaton Anderson Turfgrass Research Facility located near Mead, NE. The objectives of the investigation were to: 1) Determine irrigation and potassium nutrition treatment effects on Kentucky bluegrass (Poa pratensis L.) quality when maintained under fairway conditions; 2) Assess irrigation and potassium nutrition effects on soil and leaf tissue potassium content; and 3) Determine the effects of irrigation replacement on potential water conservation. Irrigation treatments based on 60, 80 and 100% potential evapotranspiration (ETp) and potassium nutrition at 0, 20, 40 and 60 g K m-2 season-1 were applied in two experiments to field-grown Kentucky bluegrass maintained under fairway conditions. Turfs were mowed four times
weekly at 16 mm and clippings were removed. Turfs were uniformly trafficked to simulated fairway play conditions. Irrigation meters were used to monitor weekly water applications. Analysis of variance indicated significant interaction between irrigation and potassium nutrition treatments for leaf tissue and soil potassium content, load bearing capacity, and ball roll distance. There were no significant effects on turfgrass color, quality, thatch accumulation, shoot density, verdure, or soil compaction under the conditions of this investigation. Leaf potassium content varied from 1.67 to 2.57%. Soil potassium levels ranged from 309 to 1064 mg K kg-1 for all treatments by the end of the growing season. Ball roll distance was reduced by as much as 26% at 100% ETp and 60 g K m-2 season-1. Irrigation treatments of 60 and 80% ETp resulted in water conservation of 1131 to 2630 m3 without a significant reduction in turfgrass quality.
Impacts
Drought stress and water conservation are critical issues that the turfgrass industry must face. This research offers management options with potassium nutrition and irrigation frequency that conserve water without loss of turfgrass quality.
Publications
- No publications reported this period
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Progress 10/01/01 to 09/30/02
Outputs
The fine texture and fibrous nature of turfgrass root systems make it difficult, tedious and time consuming to measure root production, distribution and plasticity. Timely, labor-efficient methods for turfgrass root assessment would be helpful. The objectives of this study were to: evaluate Kentucky bluegrass cultivars and experimental lines for root production, depth and distribution in hydroponics; determine ability of cultivars to redistribute roots as solution levels declined; and assess production of clipping yield, verdure and topgrowth among cultivars. Georgetown produced the greates root mass and Kenblue and NE 80-88 the least. Total root production varied by 25% among the cultivars tested. Root production was greates in the 0-300 mm range for all cultivars. Root production declined with depth. Touchdown had the most roots (i.e. 27% of root mass) remaining in the hydroponic solution at the end of the study. These results support the potential to select
Kentucky bluegrass genotypes with imporved rooting characteristics, such as root distribution and plasticity. Intensively used turfs, like golf course putting greens, are exposed to wear injury. Creeping bentgrass (Agrostis stolonifera L.) has only moderate wear resistance compared to many cool and warm season turfgrasses. A series of experiments were conducted to evaluate the effects of potassium nutrition levels on A. stolonifera wear tolerance and associated plant characteristics. A randomized complete block experimental design with four replications was used in all experiments. Potassium nutrition treatments were 0, 10, 20, 30 and 40 g K m-2 season-1 with a plot size of 2.5 x 10 m. Potassium sulfate (0-0-41.5K) was used as the K-source. Potassium treatments were applied in eight equal applications made every three weeks during the growing season. Turfgrass wear tolerance, leaf tissue potassium content, shoot density, verdure, load bearing capacity (LBC), leaf blade tensile
strength (LBTS), relative turgidity, tissue moisture content and cell wall constituents were determined. Potassium nutrition levels increased wear tolerance linearly with an increase >40% between the untreated control and the 40 g K m-2 season-1 treatment. Wear tolerance was correlated (r=0.93) to LBC. Potassium nutrition levels increased total cell wall (TCW) content of plant tissue. Tissue moisture content was negatively correlated to TCW (r=-0.89) and tissue K-content (r=-0.90). These results support the role of K-nutrition in improving turfgrass wear tolerance of A. stolonifera. Improvements in TCW content, LBC, and LBTS appear to be important factors contributing to the increased wear tolerance. Turfgrass managers have the opportunity to manipulate potassium nutrition for turfgrass wear stress tolerance improvement on intensively used turfgrass sites, like golf course putting greens.
Impacts
Drought stress is a critical reason for loss of turfgrass quality and use in most growing seasons. This research identifies cultivars of Kentucky bluegrass with superior drought avoidance characteristics. Consumers could select more drought avoidant cultivars to use in their lawn and turfgrass cites.
Publications
- Kerek, M., R. A. Drijber, W. L. Powers, R. C. Shearman, R. E. Gaussoin, and A. M. Streich. 2002. Accumulation of microbial biomass within particulate organic matter of aging golf greens. Agron. J. 94:455-461.
- Erusha, K. S. and R. C. Shearman. 2002. Kentucky bluegrass cultivar rooting responses measured in hydroponics. Crop Sci. 42:848-852.
- Shearman, R. C. and J. B. Beard. 2002. Potassium nutrition effects on Agrostis palustris Huds. Wear tolerance. World Congress of Golf Journal. 4:667-675.
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Progress 10/01/00 to 09/30/01
Outputs
Creeping bentgrass is susceptible to dollar spot. In the USA golf course industry, more is spent on dollar spot control than any other disease. Fungicide treatment interval and N-nutrition influence dollar spot severity. In this study, turfgrass quality was higher and dollar spot severity was less when fungicides were applied at either 7 or 28 day intervals compared to the untreated control. Turf fertilized with 30 g N/m2/season in the absence of fungicide treatment reduced disease incidence and produce improved turfgrass quality. These results support the potential of developing an integrated dollar spot management program using nitrogen nutrition to lengthen fungicide application intervals. The sod inductry depends on rapid turfgrass establishment and cover. The influence of cultivar on son formation was investigated in Nebraska and Maryland. Sod strength and lateral spread of 103 cultivars and experimental lines were studied. The 103 entries differed in sod
strength and lateral spread at 12 and 18 months after seeding. Analysis of variance indicated no significant difference for overall sod strength responses between entries grown in Nebraska and Maryland. Lateral spread was not correlated to sod strength at either location. Therse results support the opportunity to select cultivars with improved sod production potential.
Impacts
Dollar spot has a serious impact on the quality of bentgrass fairways. More is spent on the control of this disease than any other in golf course turfs. Results of this study support the reduction of fungicide use through increased nitrogen nutrition.
Publications
- Carrow, R. N., R. R. Duncan, J. E. Worley, and R. C. Shearman. 2001. Turfgrass traffic (soil compaction plus wear) simulator: Response of Paspalum vaginatum and cynodon spp. Int. Turf. Soc. J. 9:253-259.
- Carrow, R. N., R. R. Duncan, and R. C. Shearman. 2001. Providing relevant information to turfgrass managers: Challenges and implications. Int. Turf. Soc. J. 9:53-61.
- Shearman, R. C., T. R. Turner, K. N. Morris, R. E. Gaussoin, M. R. Vaitkus, and L. A. Wit. 2001. Sod strength and lateral spread of Poa pratensis cultivars and experimental lines. Int. Turf. Soc. J. 9:928-934.
- Shearman, R. C., R. N. Carrow, L. A. Wit, R. R. Duncan, L. E. Trenholm, and J. E. Worley. 2001. Turfgrass traffic simulators: A description of two self-propelled devices simulating wear and compaction stress injury. Int. Turf. Soc. J. 9:347-353.
- Watkins, J. E., R. C. Shearman, R. E. Gaussoin, W. K. Cecil, M. Vaitkus, and L. A. Wit. 2001. An integrated approach to dollar spot management on a bentgrass fairway. Int. Turf. Soc. J. 9:723-729.
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Progress 10/01/99 to 09/30/00
Outputs
This project was initiated on 7 June 1996. Kentucky bluegrass cultivars were evaluated for rooting depth, distribution, and drought avoidance characteristics. Total top growth varied among cultivars by 42%. Cultivars differed in root plasticity. Baron, Birka, Challenger, Dormie, Eclipse and Touchdown produced rooting values in excess of 20 mg at the 600-700 mm rooting depth. Touchdown had the highest value for percentage support root growth at 27% and NE 80-88 had the lowest value of 8.7%. Touchdown had the lowest leaf firing value after 63 days exposure to drought and recovered from drought stress injury by nearly 85% at 30 days after drought stress was terminated.
Impacts
Kentucky bluegrasses differ in their drought avoidance capabilities. Turfgrass managers can select cultivars with deep, extensive root systems and enhanced drought stress recovery.
Publications
- K. S. Erusha, R. C. Shearman, and L. A. Wit. 1999. A device to measure turfgrass load bearing capacity under field conditions. Crop Sci. 39:1516-1517.
- Kyoung-Nam Kim, R. C. Shearman, and T. P. Riordan. 1999. Top growth and rooting responses of tall fescue cultivars grown in hydroponics. Crop Sci. 39:1431-1434.
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Progress 10/01/98 to 09/30/99
Outputs
Turfgrasses can bear some weight before they are crushed. This load bearing capacity (LBC) provides a cushioning effect that protects crown tissue from a certain degree of traffic injury and its subsequent stress. The more LBC a turf has, the less potential traffic injury may be expected. A device was designed, constructed and tested under field conditions to measure turfgrass LBC. The LBC device was constructed to be lightweight and easy to handle. Operator-applied pressure compressed the turfgrass canopy to a predetermined endpoint. The resistance required to reach this endpoint was measured as force by a load transducer. The device was used to measure LBC of mature turfs of `Texoka' buffalograss (Buchloe dactyloides (Nutt.) Engelm.), `Parade' Kentucky bluegrass (Poa pratensis L.), `Kentucky 31' and `Mustang' tall fescue (Festuca arundinacea Screb.), and `Meyer' zoysiagrass (Zoysia japonica Steud.). The LBC device successfully separated turfgrasses species and
cultivars. Zoysiagrass and buffalograss had the highest and lowest LBC values for the species tested. Intraspecific differences of tall fescues were successfully separated, with Mustang having a greater LBC than Kentucky 31. More testing is needed to assess the ability of the LBC device to detect potential differences among cultural practice treatments, like mowing heights and nutritional rates, and screening turfgrass selections for stiffness and rigidity. Use of turf-type tall fescues (Festuca arundinacea Schreb.) as a reduced input and drought resistant turfgrass species has increased in recent years. Concerns have been expressed about the rooting responses of cultivars classified as turf-type and dwarf-type. Turf- and dwarf-type tall fescues may lack the potential drought avoidance characteristics associated with cultivars, like Kentucky 31. This study was conducted under greenhouse conditions to determine whether potential differences in top and root growth responses exist among
tall fescue cultivars, experimental lines and growth types. Sixteen cultivars and experimental lines, representing four growth-types (i.e. dwarf, turf, intermediate, and forage) were evaluated. Tall fescue cultivars, experimental lines, and growth-types differed in top growth and rooting responses. All cultivars and lines, except Jaguar and Kenhy, produced roots to 750 millimeters. Dwarf and turf-type cultivars and lines had the best responses for total root production and distribution under the conditions of this study. Silverado, Eldorado, and Trailblazer and 516 had relatively high verdure yields, low clipping yields, and a reduced clipping yield to verdure ratio. Results from this study refute concerns expressed by some persons in the turfgrass industry, regarding the potential for reduced depth and extent of rooting in dwarf- and turf-type tall fescues. These data further support the presence of genotypes with abilities to express deep, extensive root systems and favorable
characteristics for drought avoidance potential.
Impacts
The LBC device offers rapid assessment of turfgrass were tolerance and can be used to quickly evaluate turfgrass selections in breeding programs designed to improve turfgrass traffic stress tolerance. These data further support the presence of genotypes with abilities to express deep, extensive root systems and favorable characteristics for drought avoidance potential.
Publications
- Erusha, K.S., R.C. Shearman and L.A. Wit. 1999. A Device To Measure Turfgrass Load Bearing Capacity Under Field Conditions. Crop Science. 39:(In press).
- Kyoung-Nam, Kim, R.C. Shearman and T.P. Riordan. 1999. Top Growth and Rooting Responses of Tall Fescue Cultivars Grown in Hydroponics. Crop Science. 39:(In press).
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Progress 10/01/97 to 09/30/98
Outputs
This project was initiated on 7 June 1996. Overall perennial ryegrass cultivar performance reflected severe disease pressure, supra-optimal temperature stress during late-July and August, and low mowing heights. Mean quality ratings ranged from 3.2 to 7.6, with 9.0 being ideal turf and 6.0 being acceptable fairway turfgrass quality. Seasonal differences in cultivar performance were noted. Eighteen cultivars exhibited low to very low brown patch incidence. Kentucky bluegrass cultivars establish in the fall of 1995 differed in stand density, late summer and fall turfgrass quality, and sod tensile strength. Thirty- eight cultivars had sod tensile strength values exceeding 100 kg, which was consider an acceptable level for handling. A low input Kentucky bluegrass cultivar evaluation with 21 entries was investigated for adaptation to Nebraska growing conditions. Quality ratings ranged from 5.5 to 7.0 with 18 entries performing at acceptable,6.0, or greater. Manhattan,
Manhattan II, and a blend of the two perennial ryegrass cultivars were maintained with nitrogen rates of 0, 10, 20, and 40 g m-2 year-1. There was a negative relationship between nitrogen rate and brown patch (Rhizoctonia solani). Significant nitrogen rate by cultivar interaction indicated Manhattan II and the blend displayed the least incidence of brown patch at the 40 g N m-2 treatment.
Impacts
(N/A)
Publications
- Shearman, R. C. 1997. Recent turfgrass species and cultivar developments. Agronomy Abstracts. Am. Soc. Agron. Madison, WI. P. 343.
- Kyoung-Nam, Kim and R. C. Shearman. 1997. A three-year study on the leaf and soil nitrogen contents influenced by irrigation frequency, clipping return or removal and nitrogen rate in a creeping bentgrass fairway. Korean Turfgrass Sci. 11(2): 105-115.
- Frank, K. W., R. E. Gaussoin, J. E. Watkins, and R. C. Shearman. 1998. Nitrogen and Blending Effects on Disease Severity in Perennial Ryegrass. Agronomy Abstracts. Am. Soc. Agron. Madison, WI. P. 138.
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Progress 10/01/96 to 09/30/97
Outputs
This project was initiated on 7 June 1996. Overall perennial ryegrass cultivar performance reflected sever winter injury, poor spring and early-summer growing conditions. Mean quality ratings ranged from 2.2 to 6.3, with 6.0 considered to be acceptable fairway turfgrass quality. Seasonal differences in cultivar performance were noted. Eighteen cultivars exhibited low to very low brown patch incidence. Kentucky bluegrass cultivars establish in the fall of 1995 differed in stand density, late summer and fall turfgrass quality, and sod tensile strength. Thirty-eight cultivars had sod tensile strength values exceeding 100 kg, which was consider an acceptable level for handling.
Impacts
(N/A)
Publications
- Shearman, R. C. 1997. Recent turfgrass species and cultivar developments. Agronomy Abstracts. Am. Soc. Agron. Madison, WI. P.
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Progress 10/01/95 to 09/30/96
Outputs
This project was initiated on 7 June 1996. Research has been initiated to identify means of reducing inputs, such as mowing, watering, and fertilizer and pesticide applications for intensively managed and used turfgrass systems, while maintaining turfgrass quality and function. Turfgrass species and cultivar adaptation evaluations for Kentucky bluegrass (Poa pratensis L.), perennial ryegrass (Lolium perenne L.) and tall fescue (Festuca arundinacea Shreb.) were planted in the 1996 growing season. A trafficking device was developed to simulate turfgrass traffic stress and injury on the cultivar and management experiments. The device simulates foot and vehicular wear injury and compaction stress. A five year study on golf course putting green establishment, readiness for play, and post- establishment care was started in late-August. This study will evaluate the impact of establishment practices on readiness to play, long-term putting green quality and function, and
microbial activity. This study involves research support from colleagues in agronomy, horticulture, and plant pathology.
Impacts
(N/A)
Publications
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