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Marco Volterrani, Nicola Grossi, Monica Gaetani, Lisa Caturegli, Aimila-Eleni Nikolopoulou, Filippo Lulli and Simone Magni

an increase in the rate of shoot formation from crowns of ‘Tifton 85’ common bermudagrass treated with EP. Most information on PGRs is related to field applications for biomass reduction, and little is known about stolon growth regulation in pot

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Itani Tshivhandekano, Fhatuwani Nixwell Mudau and Thilivhali Emmanuel Tshikalange

demonstrated that early-applied N levels ranging from 75 to 225 kg·ha –1 improved growth and quality in cultivated bush tea ( Tshivhandekano et al., 2017 ). However, data are lacking to demonstrate the effect of timing and rates of N application on bush tea

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S.D. Sharma and M. Singh

, sublethal glyphosate rates can cause death of the apical meristem, consequently releasing apical dominance, allowing production of lateral branches. These symptoms appeared in ivyleaf morning-glory in this study with the application of glyphosate. Koger et

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Todd C. Einhorn, Yan Wang and Janet Turner

, 2007 ). Moreover, split applications of GA 3 did not improve fruit quality compared with single applications at the same rate for ‘Bing’ and ‘Lambert’ ( Facteau et al., 1985a ) or ‘Sweetheart’ ( Kappel and MacDonald, 2002 ), implying that timing of

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Julie Fulenwider* and David Creech

General guidelines for the fertilization of azaleas in Southern landscapes often suggest applications be made after bloom. Early fertilizations are thought to encourage earlier blooms which are more likely to be damaged by spring freezes. Three years of data will be presented. Treatments include four fertilization rates, and various times of application from early (December-January) to late (March-April). Four to six varieties were evaluated (depending on the year of the study) in the SFA Ruby M. Mize Azalea Garden and in plantings on the Stephen F. Austin State Univ. campus. A randomized complete block design was utilized with three plants per replication. Influence of timing and rate of fertilizer application on bloom date and persistence. Influence of fertilizer treatments on leaf nutrient concentrations will be presented.

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Michael W. Smith, Becky S. Cheary and Becky L. Carroll

Nitrogen was applied between 1996 and 2002 to grafted `Mohawk' pecan (Carya illinoinensis Wangenh. C. Koch.) trees at 75 or 150 kg·ha-1 either as a single application in March or as a split application with 60% applied in March and 40% the first week of June. In 1997 and 2001, a spring freeze damaged developing shoots and buds, resulting in a small, noncommercial crop and the June portion of the N application was withheld. Nitrogen was also applied during the first week in October at 0 or 50 kg·ha-1 N if the crop load before fruit thinning in August was ≥40% fruiting shoots. There were few differences in the percentage of fruiting shoots or cluster size associated with N rate or applying N as a single or split application. Leaf N concentrations were either not affected by treatment or the results were inconsistent. Omitting the June application when a crop failure occurred did not affect the percentage of fruiting shoots the following year. October N application either did not affect or reduced the percentage of fruiting shoots the following year, and had no influence on leaf N concentration in July or October. These results indicate that the only advantage of a split N application is the option of withholding the second portion in the event of a crop failure. However, the added expense associated with splitting the N application versus the risk of crop failure must be assessed for each situation to determine if this is a sound economic practice. These data do not support an October N application when the crop is ≥40% fruiting shoots to reduce irregular bearing.

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Guihong Bi, Carolyn F. Scagel and Richard Harkess

or quality ( Yeager et al., 1993 ). To optimize N fertilizer management in hydrangea production, knowledge of how rate and method of N fertilizer application influence plant performance is essential. Published literature on N use (optimum amount

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Thomas H. Yeager

Ilex vomitoria Ait. `Nana' root and-shoot growth increased as rate of fertilizer applied from a 6N-1P-3K solution increased from 0.5 to 2.5 g N/3-liter container during a 26-week experiment. Percentage of applied N, P, and Kin the plant and growth medium decreased as N applied increased. Dividing the fertilizer among one, two, or four applications per week resulted in similar use of applied N, P, and K. Shoot dry weights for the 0.5 g N/container treatment were less than for the Osmocote (18N-2.6P-10K) treatment (2.5 g N/container), but the percentage of applied N, P, and K in the plant and growth medium (55%, 42%, and 75%, respectively) was greater than for the Osmocote treatment (31%, 15%, and 27%, respectively).

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G. Stephen Crnko, Edward W. Bush and Allen D. Owings

A study was initiated to determine the effects of fall fertilization, specifically N application rate and additions of supplemental K on the production of woody ornamental shrub species. The influence of two slow-release sources of K (4- and 8-month) in the form of K2SO4, three K application rates (0, 1, 2 lb/yd3), and four incorporated application rates of N (0, 1, 2, and 3 lb/yd3) from Osmocote Plus+ 15-9-11 were evaluated on the growth of `Fisher Pink' Indian azalea, glossy abelia, and `Tuscarora' crape myrtle. Growth of `Fisher Pink' azalea, as determined by shoot height and shoot width, increased as N rate increased from 1 to 3 lb/yd3 when compared to the control. The resulting growth index improved at the 2 and 3 lb/yd3 N rate when compared to the 0 and 1 lb/yd3 N rates. Height and width of glossy abelia at the 1 lb N rate with or without supplemental K applications increased when compared to some glossy abelia at the 3 lb N rate (primarily those with supplemental K). Glossy abelia at the 2 lb/yd3 N rate with 2 lb/yd3 N from 4-month 0-0-46 had significantly greater shoot dry weight when compared to the 3 lb/yd3 N rate with 2 lb/yd3 N from 8-month 0-0-46. The 1 to 3 lb/yd3 N application rate had more of a response on growth index, visual quality, and visual color on `Tuscarora' crape myrtle as compared to the 0 lb/yd3 N rate. In this study, the potential influence of supplemental K applications on plant growth was mostly evident for glossy abelia at the 2 lb/yd3 N rate and was not evident on azalea or crape myrtle.

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Robert Wiedenfeld

Onion production requires N fertilization, yet use efficiency of applied N is low. Improvements may be possible with a better understanding of plant growth and nutrient requirements over time. Onion growth and nutrient uptake was extremely slow during the winter months following planting, then increased substantially in the spring. Onion leaf N concentrations declined with age, while bulb N concentrations fluctuated with growing conditions but showed no longterm trend. Responses to N application were due primarily to timing and less to rate applied. Nitrogen uptake increased in some cases very quickly following N application, and in other situations was still evident after 6½ months. Yield increases, however, occurred only for preplant and winter fertilizer applications, not for spring application. Yield responses to both timing and rate varied by cultivar, with the later maturing cultivar doing best at the highest rate of preplant and the higher 2 rates of the winter applied N fertilizer.