Effects of clipping and nitrogen fertilization on tiller development and flowering in Kentucky bluegrass

1993 ◽  
Vol 73 (2) ◽  
pp. 569-575 ◽  
Author(s):  
D. J. Thompson ◽  
K. W. Clark
Keyword(s):  
Key Words ◽  
Nitrogen Fertilization ◽  
Poa Pratensis ◽  
Cold Treatment ◽  
Kentucky Bluegrass ◽  
Shoot Density ◽  
Stem Length ◽  
Seed Harvest ◽  
Seed Field

One hundred cores (10 × 10 × 12 cm) of Kentucky bluegrass (Poa pratensis L. ’Nugget’) were removed from an established seed field, potted, and subjected to two clipping treatments after seed harvest (clipping at 2.5 cm to simulate straw and mechanical stubble removal and clipping at 7.5 cm to simulate straw removal) and two fertilizer treatments (solutions with and without the equivalent of 100 kg ha−1 of N). The plants were then subjected to a cold treatment (98 d at 2.5 °C) to induce flowering. Added N increased the number of large tillers formed before the cold treatment, and produced similar increases in the number of initiated tillers and flowering shoots. Added N resulted in larger inflorescences with more spikelets. Close clipping (2.5 cm) did not affect tillering or flowering shoot density, but reduced stem length and resulted in smaller inflorescences with fewer spikelets. Key words: Kentucky bluegrass, nitrogen, clipping height, tillering and flowering

Quantitative and qualitative responses of an established Kentucky bluegrass (Poa pratensis L.) turf to N, P, and K additions

2005 ◽  
Vol 85 (1) ◽  
pp. 193-204 ◽  
Author(s):  
Abdo Badra ◽  
Léon-Etienne Parent ◽  
Yves Desjardins ◽  
Guy Allard ◽  
Nicolas Tremblay
Keyword(s):  
Poa Pratensis ◽  
Block Design ◽  
Kentucky Bluegrass ◽  
The United States ◽  
Shoot Density ◽  
Qualitative Response ◽  
K Fertilizer ◽  
Soil Test P ◽  
N Rates ◽  
Qualitative Responses

Kentucky bluegrass is a common turf species used on golf courses, sports fields, municipal parks, sod farms, road banks, as well as residential and school yards. Our objective was to determine the effects of N, P, K rates on turfgrass quantitative response (clipping yield and underground turf biomass) and qualitative response (shoot density and foliage colour) under a continuous clipping removal. A 3-yr field study was conducted on two sites, a sand that met the specifications of the United States Golf Association (USGA) and a loam. The factorial experiment was arranged in a randomized complete block design with four replicates and different levels of three nutrients, N (0 or 50 to 300 kg ha-1 yr-1), P (0 or 21.8 to 87.3 kg P ha-1 yr-1), and K (0 or 41.7 to 250 kg K ha-1 yr-1). The maximum clipping yield was produced at the rate of 200 kg N ha-1 yr-1 in the loam and 300 kg N ha-1 yr-1 in the sand. Increasing N rates linearly reduced underground turf biomass. Added P and K had no effect on clipping yield and underground turf biomass. Nitrogen significantly improved shoot density and foliage colour. However, equivalent shoot density and colour ratings required 40 to 80 kg more N ha-1 yr-1 in the sand compared to the loam. Phosphorus and K had no significant effect on shoot density and colour in the loam. Colour response to P and K depended on N rates in the sand. Fertilizer units needed to increase soil test P averaged 6 kg added P ha-1 mg-1 PM-III kg-1 across soil types. To replenish soil K, 7 kg K ha-1 per mg KM-III kg-1 were required in the sand, and 3 kg K ha-1 per mg KM-III kg-1 in the loam. Phosphorus and K fertilizer programmes should account for P and K removals to maintain low to medium fertility levels for P, and medium for K when conditions are similar to those in this research. Key words: Turfgrass clipping yield, underground turf biomass, turfgrass shoot density, turfgrass foliage colour, Kentucky bluegrass fertilization

INFLUENCE OF NITROGEN FERTILIZATION AND MECHANICAL STUBBLE REMOVAL ON SEED PRODUCTION OF KENTUCKY BLUEGRASS IN MANITOBA

1989 ◽  
Vol 69 (3) ◽  
pp. 939-943 ◽  
Author(s):  
D. J. THOMPSON ◽  
K. W. CLARK
Keyword(s):  
Seed Production ◽  
Seed Yield ◽  
Nitrogen Fertilization ◽  
Field Experiments ◽  
Poa Pratensis ◽  
Kentucky Bluegrass ◽  
N Fertilization ◽  
Shoot Height ◽  
Straw Yield ◽  
Panicle Weight

Three field experiments were performed to determine the effects of fall nitrogen fertilization and post-harvest mechanical stubble removal (to 2.5 cm) on seed yield in Kentucky bluegrass (Poa pratensis L. ’Nugget’). In all experiments, N fertilization and stubble removal increased seed yield. Increases were greater in a 3-yr-old than in a 5-yr-old stand. Nitrogen fertilization increased panicle density, panicle weight, shoot height and straw yield. Stubble removal increased panicle density, reduced panicle weight, shoot height, and straw yield and increased harvest index.Key words: Nitrogen, stubble removal, seed, Kentucky bluegrass

Nitrogen fertilization of the forage crop: its effect on the yield and agronomic efficiency of Nitrogen

2020 ◽  
Vol 2 (1) ◽  
pp. 26-32
Author(s):  
Liliana Vega-Jara ◽  
Keyword(s):  
Key Words ◽  
Plant Height ◽  
Nitrogen Fertilization ◽  
Dry Matter ◽  
Stem Length ◽  
Agronomic Efficiency ◽  
Forage Crop ◽  
Significance Level ◽  
Fresh Biomass ◽  
Key Words Nitrogen

The goal was to evaluate the effect of nitrogen fertilization on the yield and EAN (agronomic efficiency of nitrogen) of the forage oat crop. To meet this goal, an experiment with a DBCA design was carried out, using 6 treatments: T0 (control), T1 (50-20-60), T2 (100-20-60), T3 (180-20-60), T4 (250-20-60) and T5 (350-20-60), repeated three times, in San Cristobal, Huacrachuco. The evolution of plant height, number of tillers per plant, fresh biomass, dry matter,% fiber and the agronomic efficiency of nitrogen (EAN) were determined. The data were analyzed with ANOVA and LSD test at 5% significance level. Treatments T5 and T4 reached higher values in stem length, higher yields of fresh biomass and dry matter by m2 . Fertilization did not change the number of tillers per plant and the% of fiber. However, the most optimal EAN was achieved with the dose of 100-20-60. Values higher than this dose of N could produce over fertilization without the plant using it efficiently. In conclusion, it is recommended to apply this dose (100-20-60) for having presented the best EAN, although the yields were lower with this dose, it would be the most appropriate for the efficient use of crop N. Key words: Nitrogen - San Cristobal, Huacrachuco – Forage

Effect of leaf nitrogen concentration versus CND nutritional balance on shoot density and foliage colour of an established Kentucky bluegrass (Poa pratensis L.) turf

2006 ◽  
Vol 86 (4) ◽  
pp. 1107-1118 ◽  
Author(s):  
Abdo Badra ◽  
Léon-Étienne Parent ◽  
Guy Allard ◽  
Nicolas Tremblay ◽  
Yves Desjardins ◽  
...  
Keyword(s):  
Poa Pratensis ◽  
Block Design ◽  
Nitrogen Concentration ◽  
Principal Component ◽  
Kentucky Bluegrass ◽  
Shoot Density ◽  
Leaf Nitrogen ◽  
N Concentration ◽  
Randomized Block Design ◽  
N Status

A 3-yr field study was conducted in a loam and a sand site to determine the effects of N, P, and K application rates on N status, shoot density and foliage colour of Kentucky bluegrass clippings and to derive critical N values. The experiment was arranged in a completely randomized block design with four replicates and three nutrients, N (0 or 50 to 300 kg ha-1 yr-1), P (0 or 21.8 to 87.3 kg P ha-1 yr-1), and K (0 or 41.7 to 250 kg K ha-1 yr-1), equally broadcast six times per growing season. We examined N concentration values, log-transformed N concentration values, and CND values for compositional nutrient simplexes comprising one (VN1), three (VN3), five (VN5), or 11 (VN11) macro- and micro-nutrients. Critical values for N expressions were obtained from linear relationships with targeted visual shoot density and foliage colour ratings that were closely related to each other (R2 = 0.92). The highest coefficients of determination (0.975 to 0.980) were obtained with VN5 and VN11. The VN5 values were consistent with literature data and across experimental sites, and were the most successful (99% success) in diagnosing N sufficiency in 328 qualified specimens from commercial sod farms. Compared with raw concentrations, the CND transformation reduced from 0.6 to 0.1 the degree of inter-correlation among nutrients in principal component analysis and was amenable to a χ2 distribution of CND indices. Using a critical imbalance index (CNDr2) of 5.6as χ2 value, and a critical CND IN2 index of 1.5 for a 5-nutrient simplex, we diagnosed as imbalanced 179 qualified specimens of which 110 specimens presented excessively high N level among the 328 qualified specimens in commercial stands. The proposed five-nutrient CND norms proved to be effective in diagnosing N status in Kentucky bluegrass clippings across experimental, literature, and survey data sets. Key words: Plant tissue nutrient diagnosis, DRIS, CND, Kentucky bluegrass nitrogen fertilization, turfgrass shoot density, turfgrass foliage colour

Silvertop in perennial grass seed production: Effects of type and timing of biotic stresses

2021 ◽  
Author(s):  
Julie Soroka ◽  
Bruce D. Gossen
Keyword(s):  
Seed Production ◽  
Poa Pratensis ◽  
Perennial Grass ◽  
Kentucky Bluegrass ◽  
Development Stage ◽  
Perennial Grasses ◽  
Grass Species ◽  
Biotic Stresses ◽  
Seed Harvest ◽  
Bromus Riparius

Seed production of perennial grasses is an important industry in Canada, but many fields exhibit high proportions of sterile heads with characteristic symptoms in a condition known as silvertop. In a 3-yr field study, biotic stress treatments were applied to caged plots of Kentucky bluegrass (<i>Poa pratensis</i>) and meadow bromegrass (<i>Bromus riparius</i>) to assess their effects on silvertop incidence. Treatments were: 1) control, 2) addition of grass-feeding insects, primarily grass plant bugs (Miridae), 3) inoculation with <i>Fusarium poae</i> spores, 4) both insects and spores, and in one year, 5) mechanical piercing of seed heads above the last node. Additionally, cores of the two grass species were potted and removed from the field in spring in each of 2 years. After 2-, 4-, and 6-wk intervals in a cold room at 4° C to stagger plant development stage, the five treatments were applied to caged plants of both grasses, which were maintained in a greenhouse until seed harvest. In both studies, the numbers of healthy seed heads, percentage of heads with silvertop, and seed weights were determined. In the field, stress treatments infrequently and inconsistently affected silvertop levels. Regression showed that the relationship between silvertop and seed yield, although significant, explained little of the variability in yield. Silvertop developed in all treatments in the greenhouse; treatments had no effect on silvertop levels, which were highest in plants treated at the R1 (boot) growth stage. This suggests that the boot stage of the two grass species is most vulnerable to silvertop occurrence.

scholarly journals Sand Topdressing Applications Improve Shear Strength and Turfgrass Density on Trafficked Athletic Fields

2010 ◽  
Vol 20 (5) ◽  
pp. 867-872 ◽  
Author(s):  
Alexander R. Kowalewski ◽  
John N. Rogers ◽  
James R. Crum ◽  
Jeffrey C. Dunne
Keyword(s):  
Shear Strength ◽  
Root Zone ◽  
Sandy Loam ◽  
System Development ◽  
Poa Pratensis ◽  
Dry Weight ◽  
Kentucky Bluegrass ◽  
Shoot Density ◽  
Surface Shear ◽  
Surface Stability

Drain tile installation into a native-soil athletic field and subsequent sand topdressing applications are cost-effective alternatives to complete field renovation. However, if cumulative topdressing rates exceed root system development, surface stability may be compromised. The objective of this research was to evaluate the effects of cumulative topdressing, over a compacted sandy loam soil, on the fall wear tolerance and surface shear strength of a kentucky bluegrass (Poa pratensis)–perennial ryegrass (Lolium perenne) stand. Research was initiated in East Lansing, MI, on 10 Apr. 2007. A well-graded, high-sand-content root zone (90.0% sand, 7.0% silt, and 3.0% clay) was topdressed at a 0.25-inch depth [2.0 lb/ft2 (dry weight)] per application, providing cumulative topdressing depths of 0.0, 0.5, 1.0, 1.5, or 2.0 inches applied from 11 July to 15 Aug. 2007. Fall traffic was applied twice weekly to all treatments from 10 Oct. to 3 Nov. 2007. In 2008, topdressing applications and traffic, as described earlier, were repeated on the same experimental plots. Results obtained from this research suggest that the 0.5-inch topdressing depth applied over a 5-week period in the summer will provide improved shoot density and surface shear strength in the subsequent fall. Results also suggest that topdressing rates as thick as 4.0 inches accumulated over a 2-year period will provide increased shoot density, but diminished surface shear strength.

scholarly journals Preliminary Observations on Physiological Responses of Three Turfgrass Species to Traffic Stress

2008 ◽  
Vol 18 (1) ◽  
pp. 139-143 ◽  
Author(s):  
Lie-Bao Han ◽  
Gui-Long Song ◽  
Xunzhong Zhang
Keyword(s):  
Antioxidant Activity ◽  
Membrane Permeability ◽  
Tall Fescue ◽  
Poa Pratensis ◽  
Physiological Responses ◽  
Chlorophyll Concentration ◽  
Kentucky Bluegrass ◽  
Shoot Density ◽  
Cell Membrane Permeability ◽  
Leaf Water Content

Traffic stress causes turfgrass injury and soil compaction but the underlying physiological mechanisms are not well documented. The objectives of this study were to investigate the physiological responses of kentucky bluegrass (Poa pratensis), tall fescue (Festuca arundinacea), and japanese zoysiagrass (Zoysia japonica) to three levels of traffic stress during the growing season under simulated soccer traffic conditions. Relative leaf water content (LWC), shoot density, leaf chlorophyll concentration (LCC), membrane permeability, and leaf antioxidant peroxidase (POD) activity were measured once per month. The traffic stress treatments caused a reduction in LWC, shoot density, LCC, and POD activity, and an increase in cell membrane permeability in all three species. Japanese zoysiagrass had less electrolyte leakage, and higher POD activity and shoot density than both kentucky bluegrass and tall fescue. The results suggest that turfgrass tolerance to traffic stress may be related to leaf antioxidant activity. Turfgrass species or cultivars with higher leaf antioxidant activity may be more tolerant to traffic stress than those with lower antioxidant activity.

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