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Ian R. Rodriguez, Grady L. Miller, and L.B. McCarty

For drainage, turfgrass is often established on sand-based soils, which are typically nutrient-deficient and require supplemental fertilization. The objective of this study was to determine the optimum N-P-K fertilizer ratio for establishing bermudagrass from sprigs in sand. `FloraDwarf' and `Tifdwarf' bermudagrasses [Cynodon dactylon (L.) Pers. × C. transvaalensis Burt-Davy] were sprigged on a United States Golf Association (USGA) green [85 sand: 15 peat (v/v)] in Aug. 1996 at the Univ. of Florida's Envirogreen in Gainesville, Fla. `TifEagle' bermudagrass was sprigged on a USGA green [85 sand: 15 peat (v/v)] and `Tifway' bermudagrass [C. dactylon (L.) Pers.] was sprigged on native soil at Clemson Univ. in Clemson, S.C. in May 1999. Treatments consisted of fertilizer ratios of 1N-0P-0.8K, 1N-0P-1.7K, 1N-0.4P-0.8K, 1N-0.9P-0.8K, and 1N-1.3P-0.8K applied based on a N rate of 49 kg·ha-1/week for 7 weeks. Growth differences were apparent among cultivars. A 1N-0P-0.8K or 1N-0P-1.7K ratio is insufficient for optimum growth of bermudagrass during establishment, even when planted on a soil high in P. Increased coverage rate with additional P was optimized at a ratio of 1N-0.4P at all four sites. Increased coverage with P was greatest on the sand-based greens, probably due to the very low initial P levels of the soils. On two of the sand-based greens, P in excess of a 1N-0.4P ratio decreased coverage rate.

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Michael Maurer* and Justin Weeaks

Throughout much of the Southwestern United States, poor quality water and limited water resources require innovative methods to conserve water. No research to date has indicated whether seeded bermudagrass Cynodon dactylon can be established by using subsurface drip irrigation (SDI). In 2001 (Expt. I) and 2002 (Expt. II), seeded bermudagrass was evaluated for establishment using SDI. Treatments consisted of emitters and tubing spaced at 30, 46, and 61 cm. The control treatment consisted of pop-up sprinklers. Salinity accumulation is a concern when irrigating turfgrass in areas of poor water quality and low annual rainfall. Salinity accumulation was visible at the soil surface during establishment in 2001, but turfgrass showed no visible signs of stress due to salinity. In 2002, substantial rainfall reduced salinity accumulation during establishment as salinity was not present on the soil surface. Salinity accumulation was greater in most months at the 0-15 cm depth in both years compared to the 15-30 cm depth. Full turfgrass coverage (≥90%) for the control plots in 2001 was about 8.5 weeks and the SDI treatments had complete coverage in 10 weeks. Turfgrass coverage for all treatments in 2002 was 9 weeks. Expt. II had a slightly faster establishment rate due to greater rainfall and different soil characteristics than that of Expt. I. Root count and depth of roots for both years showed roots to 61 cm depth in all treatments. A general trend of higher salinity accumulation at the midpoint between tubing was seen in Expts. I and II. However, after significant rainfall salinity levels returned to concentrations comparable to initial soil salinity concentrations in both years. This research documents the ability to successfully establish seeded bermudagrass using SDI.

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Anne M. Lockett, Dale A. Devitt, and Robert L. Morris

Population growth and water limitations in the southwestern United States have led to golf courses in many communities to be encouraged or mandated to transition to reuse water for irrigation purposes. A monitoring program was conducted on nine golf courses in the Las Vegas valley, NV, for 4.5 years to assess the impact of reuse water on soil–turfgrass systems {bermudagrass [Cynodon dactylon (L.) Pers.], perennial ryegrass (Lolium perenne L.), bentgrass (Agrostis palustris Huds.)}. The nine courses selected included three long-term reuse courses, three fresh water courses, and three courses expected to transition to reuse water during the monitoring period. Near-surface soil salinity varied from 1.5 to 40.0 dS·m−1 during the study period with the highest peaks occurring during summer months and on long-term reuse irrigated fairways. Although soil salinity at several depths on fairways and greens increased after transition to reuse water, this did not lead to a systematic decline in leaf xylem water potential (ΨL) or color. When the data were grouped as fresh, transition, or reuse irrigated, soil salinity on reuse courses were statistically higher (P < 0.05) than fresh and transitional courses, yet plant response on reuse courses was not statistically different (P > 0.05) than that observed on fresh courses. The fact that summertime plant parameter values often declined under lower salinity levels and the electrical conductivity of the irrigation water was rejected as a significant variable in all backward regression analysis to describe plant response indicated that management differed significantly from course to course. We conclude that proper irrigation management, based on a multitiered feedback system (soil–plant–atmospheric monitoring), should be able to maintain favorable salt balances and plant response as long as irrigation volumes are not restricted to where deficit irrigation occurs.

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Alan L. Wright, Tony L. Provin, Frank M. Hons, David A. Zuberer, and Richard H. White

Application of organic amendments can increase dissolved organic C (DOC) concentrations, which may influence movement of nutrients and heavy metals in soils. The objectives of this study were to investigate the influence of compost sources and application rates on concentrations of soil DOC, NO3-N, and extractable P over 29 months after a one-time application of compost to bermudagrass [Cynodon dactylon (L.) Pers.] turf. Few differences were evident between compost sources for soil total organic C (TOC), DOC, and NO3-N. However, the initial P content of compost sources significantly influenced soil extractable P. Increasing the rate of compost application increased soil TOC initially, but levels remained fairly stable over time. In contrast, DOC continued to increase from 3 to 29 months after application, suggesting that compost mineralization and growth of bermudagrass contributed to DOC dynamics in soil. Dissolved organic C was 98%, 128%, 145%, 175%, and 179% greater 29 months after application of 0, 40, 80, 120, and 160 Mg compost/ha, respectively, than before application. Rate of compost application had less effect on DOC than TOC, as DOC concentrations appeared controlled in part by bermudagrass growth patterns. Soil NO3-N was generally unaffected by compost application rate, as NO3-N decreased similarly for unamended soil and all compost treatments. Soil extractable P initially increased after compost application, but increasing the application rate generally did not increase P from 3 to 29 months. Seasonal or cyclical patterns of TOC, DOC, and extractable P were observed, as significantly lower levels of these parameters were observed in dormant stages of bermudagrass growth during cooler months.

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Bernd Leinauer, Matteo Serena, and Devesh Singh

A field experiment was conducted at New Mexico State University to investigate the effect of seeding rates and ZEBA polymer [starch-g-poly (2-propenamide-co-propenoic acid) potassium salt] seed coating on the germination and establishment of warm- and cool-season grasses, and cool-season blends and mixtures. Grasses were established at recommended and reduced (50% of recommended) seeding rates with coated and uncoated seeds under two irrigation regimes (98% and 56% reference evapotranspiration). With the exception of ‘Bengal’ creeping bentgrass (Agrostis stolonifera), the polymer coating did not improve germination of the turfgrasses tested 22 days after seeding (DAS). However, at the end of the establishment period (92 DAS), plots established with ‘Bengal’, Dunes Mix [mixture of ‘Hardtop’ hard fescue (Festuca longifolia), ‘Baron’ kentucky bluegrass (Poa pratensis), ‘Barok’ sheep fescue (Festuca ovina)], ‘Panama’ bermudagrass (Cynodon dactylon), and Turf Sense™ [mixture of ‘Baronie’ kentucky bluegrass, ‘Barlennium’ perennial ryegrass (Lolium perenne), and ‘Barcampsia’ tufted hairgrass (Deschampsia cespitosa)] achieved greater coverage (based on visual estimations) when coated seed was used compared with uncoated seed. Establishment was greater for ‘Bengal’, Dunes Mix, ‘Panama’, Turf Sense™, and Turf Saver™ [blend of ‘Barlexas II’, ‘Barrington’, and ‘Labarinth’ tall fescue (Festuca arundinacea)] when normal seeding rates were applied compared with reduced seeding rates. ‘Barleria’ crested hairgrass (Koeleria macrantha) plots did not establish, regardless of the treatments applied. Results showed that seed coating has the potential to improve establishment at recommended and reduced seeding rates and can compensate for less favorable conditions such as reduced irrigation, reduced seeding rate, or for a combination of both. At the end of the establishment period, not all grasses achieved coverage greater than 50%. Further research over a longer establishment period is needed to determine if coated seed can be beneficial in achieving full coverage.

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Dale A. Devitt, Lena Wright, Daniel C. Bowman, Robert L. Morris, and Michelle Lockett

Irrigators in arid and semiarid regions that use reuse water must maintain positive leaching fractions (LFs) to minimize salt buildup in root zones. However, with the continuous feed of NO3-N in reuse water, imposing LFs can also lead to greater downward movement of NO3-N. It is therefore essential that deep movement of NO3-N be assessed relative to nitrogen loading under such conditions. We conducted a long-term monitoring program on nine golf course fairways in southern Nevada over a 1600-d period. The fairways were predominantly bermudagrass [Cynodon Dactylon (L.) Pers.; 35 of 36 site × years] overseeded with perennial ryegrass (Lolium perenne L.; 8 of 9 courses). Courses were irrigated with fresh water, reuse water (tertiary treated municipal sewage effluent), or transitioned to reuse water during the study. Solution extraction cups were inserted at depths of 15, 45, 75, and 105 cm on fairways and sampled and analyzed for NO3-N on a monthly basis. Distribution patterns of NO3-N varied from site to site. Concentrations exceeding 100 mg·L−1 were observed at the 105-cm depth on all three long-term reuse courses. On the transitional courses, 72% of the variation in the yearly average NO3-N concentrations at the105-cm depth could be accounted for based on knowing the amount of fertilizer nitrogen (N) applied, the amount of reuse N applied, and the LF (Y = –42.5 + 0.18 fertilizer N + 0.26 reuse N –62.0 LF). Highest N fertilizer applications occurred on transition courses with little or no reduction in N applications after courses had transitioned to reuse water (pretransition courses 394 + 247 kg·ha−1 N/year versus posttransition courses 398 + 226 kg·ha−1 N/year). The results of this study indicate a need for a more scientific approach to N management on reuse irrigated courses.

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R.L. Green, R.C. Hartwig, W.E. Richie, R.H. Loeppert, and J.B. Beard

Iron-deficiency (Fe-deficiency) stress, characterized by chlorosis of leaf tissue, is a major limiting factor in turfgrass production on calcareous soils. The objectives of this study were to: 1) evaluate ferrihydrite-amended growth media and the threshold amount of Fe initially added for use in a whole-plant screening procedure for selecting cultivars that are tolerant to Fe-deficiency stress conditions; 2) measure and evaluate whole-plant growth characteristics that could be an index of Fe deficiency stress; and 3) assess the potential of using a synthetically produced Fe oxide, ferrihydrite, as a slow-release Fe fertilizer source. Iron-stress sensitive `Raleigh' St. Augustinegrass [Stenotaphrum secundatum (Walt.) Kuntze] and Fe-stress tolerant `Tifway' bermudagrass [Cynodon dactylon (L.) Pers. × C. transvaalensis Davy] cultivars were grown under glasshouse conditions in a medium consisting of quartz sand, 5% (m/m) CaCO,, and a ferrihydrite amendment providing Fe in concentrations of 0, 15, 30, 46, or 120 mg·kg-1 media, (equivalent to 2, 3, 4, 5, or 10 mg DTPA-extractable Fe/kg media). There also was a nonlimiting iron control. St. Augustinegrass was first rated for iron chlorosis 83 days after planting (DAP) while bermudagrass was first rated at 294 DAP. Initial Fe levels equivalent to 5 mg DTPA-extractable Fe/kg media showed potential for screening genotypes. Visual estimates of iron chlorosis and chlorophyll contents of leaves were the best indicators of low soil Fe availability. A single ferrihydrite soil amendment at 10 mg DTPA-extractable Fe/kg media was adequate in preventing chlorosis for the duration of the study (174 and 509 days for St. Augustinegrass and bermudagrass, respectively). Chemical name used: Diethylenetriaminepentaacetic acid (DTPA).

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G.L. Miller, L.B. McCarty, and I.R. Rodriguez

Establishment of an acceptable turfgrass quality on sand-based golf putting greens presents major agronomic and environmental challenges to turfgrass managers. The objective of this study was to evaluate of five N:P:K fertilizer ratios to aid in the establishment of bermudagrass on sand-peat (85:15 v/v). `Floradwarf' and `Tifdwarf' bermudagrass [Cynodon dactylon (L.) Pers. × C. transvaalensis Burt-Davy] were sprigged in Aug. 1996 at the Envirogreen in Gainesville, Fla. `Tifeagle' and `Tifway' bermudagrass were sprigged in May 1999 at Clemson Univ. research green in Clemson, S.C. Treatments consisted of N:P2O5:K2O ratios of 1:0:1, 1:0:2, 1:1:1, 1:2:1, and 1:3:1 applied based on an N rate of 49 kg/ha per week. Treatments were applied weekly for 7 weeks. In Gainesville, the best growth rate was achieved from the 1:1:1 ratio of N:P2O5:K2O. While the 1:2:1 and 1:3:1 plots filled in well, they did not experience the same coverage rates as plots fertilized with the 1:1:1 ratio. In Clemson, similar growth was achieved with the 1:1:1, 1:2:1, and 1:3:1 treatments. The 1:0:1 and 1:0:2 plots were slow to establish at both locations. In general there were no differences in root and shoot dry weights of grasses grown in Clemson; whereas these weights were positively correlated to growth rates in Gainesville. These studies indicate that turf will respond to P fertilizer when it is grown in a P-deficit situation and that N or K cannot substitute for balanced nutrition.

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Donald M. Vietor, Ronnie W. Schnell, Tony L. Provin, Richard H. White, and Clyde L. Munster

Incorporation or top-dressing of composted biosolids (CB) can enhance turfgrass establishment and sod properties at harvest, but soil phosphorus (P) and nitrogen must be managed to protect water quality. Alum treatment of CB could reduce soluble P concentrations in amended soil and limit runoff loss of P. The objective was to evaluate CB and Alum effects on turfgrass coverage of soil and runoff losses during ‘Tifway’ bermudagrass [Cynodon dactylon (L.) Pers. var. dactylon × C. transvaalensis Burtt-Davey] establishment from sprigs or transplanted sod. Three replications of eight treatments comprised a complete randomized design. Four treatments were composed of ‘Tifway’ sprigged in soil with and without incorporation of CB and Alum. Four remaining treatments were sods harvested from ‘Tifway’ grown with and without top-dressed CB that were transplanted with and without a surface spray of Alum. Surface coverage of ‘Tifway’ sprigged in soil mixed with inorganic fertilizer or CB was comparable to transplanted sod 25 days after planting. In contrast, Alum incorporation acidulated soil, slowed coverage rates of sprigged ‘Tifway’, and increased NH4-N runoff loss during early establishment in treatments without CB. Incorporation of Alum with CB or inorganic fertilizer in soil before sprigging reduced soil water-extractable P (WEP) more than 38% and reduced runoff loss of soluble reactive P (SRP) in three of four establishment treatments. Although SRP runoff loss from CB-amended sod was greatest among treatments, the Alum spray minimized SRP loss after transplanting. Alum effectively reduced runoff loss of SRP from CB, soil, and turfgrass sources during establishment from sprigs or sod. Additional field research is needed, but incorporated or surface sprays of Alum offer a potential new practice for mitigating runoff loss of SRP from establishing turfgrass.

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Jason J. Goldman, Wayne W. Hanna, and Peggy Ozias-Akins

`TifEagle' (2n = 3x = 27) hybrid bermudagrass [Cynodon dactylon (L.) Pers. (2n = 4x = 36) × Cynodon transvaalensis Burtt-Davy (2n = 2x = 18)] is an ultradwarf cultivar for greens, and `TifSport' (2n = 3x = 27) is a more versatile hybrid used on fairways, athletic fields, and lawns. To develope a transformation system and determine if somaclonal variation was present in regenerated plants, both cultivars were tested for their ability to produce embryogenic callus from which plants could be regenerated. Sliced nodes of both cultivars and immature inflorescences from `TifSport' were used as the explant sources. Cultures were initiated on Murashige and Skoog medium supplemented with 6.79 μm 2,4-D and 0.044 μm BA (`TifSport' and `TifEagle') or 6.79 μm 2,4-D plus 200 mg.L-1 casein hydrolysate (`TifSport'). In total, 51 plants were regenerated from callus of a single node of `TifEagle'. Nodes from `TifSport' did not produce embryogenic callus. In total, 29 plants were regenerated from callus of `TifSport' produced from immature inflorescences. These plants were grown in the field for at least one season, and 5-cm-diameter plugs were harvested, repotted in a greenhouse, and allowed to reestablish. Data on canopy height, leaf width, leaf length, and number of stolons were collected. Seven `TifEagle'-derived entries (14%) were not significantly different (α = 0.05) from `TifEagle' harvested from the breeder plot in Tifton, Ga., for all measured traits, and 41%, 24%, and 22% differed by one, two, or three measurements, respectively. Flow cytometry indicated that 33% (13 plants) of the `TifEagle' regenerants were hexaploid (2n = 6x = 54) and the rest remained triploid. One `TifSport' regenerant was significantly different (α = 0.05) for plant height.