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  • Author or Editor: James M. Spiers x
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Abstract

Varying levels of lime and/or elemental S were added to a Ruston fine sandy loam soil to determine the influence of soil pH on growth, fruit yields, and leaf nutrient (N) content of rabbiteye blueberry (Vaccinium ashei Reade). Soil pH changes were monitored monthly from Oct. 1978 to Sept. 1980, and bimonthly from Oct. 1980 to Sept. 1982. Plant growth measurements were determined yearly. Plant growth and yields were reduced greatly in soils with pH < 3.5. Increasing levels of lime did not reduce fruit yields or plant growth as much as increasing S levels. Highest yields and best growth occurred in plants grown within a soil pH range of 3.9 to 6.1. Leaf N content increased as soil pH increased up to a level of 4.5 to 5.0 and then decreased with increased soil pH levels. Soil pH seems to have a greater influence on Ca uptake than does Ca addition to the soil. Excessive uptake of Na at high pH levels and Mn at low pH levels may be limiting factors in plant growth.

Open Access
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Abstract

A field study was conducted to evaluate individual and collective influences of 3 soil moisture-supplementing practices (irrigation, incorporated peatmoss, and mulching) on root system development in ‘Tifblue’ rabbiteye blueberries (Vaccinium ashei Reade). Plants that received no water-supplementing treatments died within 3 years. Root growth was least in plants receiving only one of the 3 treatments and greatest in plants receiving all 3. Ranking of individual treatments on root dry weight production was mulch > incorporated peatmoss > irrigation. Mulching resulted in uniform root distribution from the plant crown outward, while peatmoss tended to concentrate the root system near the crown area. Incorporating peatmoss concentrated roots at the 30- to 45-cm depth, while mulching tended to concentrate the roots in the upper 15 cm of soil. In a sandy, well-aerated soil, the major factor influencing root distribution appears to be soil moisture.

Open Access
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Abstract

The effect of incorporated sphagnum peatmoss and minimal fertilization on the establishment and subsequent growth of rabbiteye blueberries (Vaccinium ashei Reade) was determined in 4 field studies conducted on typical fine sandy loam, upland mineral soils in south Mississippi. Incorporated peatmoss increased plant vigor, plant height, shoot weight, leaf chlorophyll level, and fruit yield and reduced chlorosis symptoms. First- and second-year plant growth and second-year fruit yields were reduced by either slow-release or fast-release granulated fertilizer. Soluble fertilizers produced less plant damage than granulated fertilizers but no more plant growth than no fertilization. There was a close association between over-fertilization and cholorosis symptoms.

Open Access
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Abstract

‘Tifblue’ rabbiteye blueberry (Vaccinium ashei Reade) leaves were sampled at 2-week intervals during the growing seasons of 1979 and 1980. Each sample was analyzed for 5 macronutrients and 5 micronutrients. Prediction equations for the estimation of nutrient element content on a growing season basis were calculated. Leaf elemental content patterns correlated closely between years with the exception of Fe. Leaf elemental N, P, and Zn were highest in the early season, tended to decrease until harvest, and leveled off as the growing season progressed. The levels of leaf Ca and Mg remained relatively constant through the season with lowest percentages present during harvest. Leaf contents of K, Mn, and to a lesser extent B and Na, were high during April and early May, low during harvest, and high again in October. Regression analyses for most elements were more linear from late June to early August. Therefore, optimum time for the collection of leaf samples of rabbiteye blueberries for mineral analyses appears to be a 4-week interval coinciding with the last 2 weeks of the harvest season through a 2-week period immediately following harvest.

Open Access
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Abstract

In a sand culture study, increasing N fertilizer levels (NH4–N) had no effect on stem number or leaf concentrations of K, Mg, or Zn in ‘Tifblue’ rabbiteye blueberry (Vaccinium ashei Reade). Leaf N concentration increased when N fertilizer was raised from 25 to 50 mg/liter N. Additional N fertilizer up to 100 mg N/liter did not raise percent N in leaves, but increased P and decreased Ca. Increased K levels raised leaf concentration of K but not those of other elements. High levels of Na resulted in increased N in leaves and reduced plant growth. Significant interactions indicate synergistic and/or antagonistic influences of fertilizer treatments on elemental leaf concentrations of N, P, and B.

Open Access
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Abstract

Plant yield, height, and vigor were increased and chlorosis symptoms were decreased by irrigation and/or mulching of rabbiteye blueberry (Vaccinium ashei Reade). Plant growth ratings were highest in plants receiving both irrigation and mulching. Height, vigor, and survivability of irrigated plants were about twice that of nonirrigated plants. Incorporated organic matter increased height and vigor for nonirrigated and nonmulched plants. Organic matter types and levels resulted in little difference in irrigated plant growth. Incorporated organic matter, mulching, and irrigation all improved the soil moisture condition and enhanced the growth of rabbiteye blueberries.

Open Access
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Abstract

Bud development in ‘Tifblue’ rabbiteye blueberry (Vaccinium ashei Reade) was reduced with increasing levels of soil-applied paclobutrazol (PB). Flowering was delayed from 10 to 15 days on plants receiving ≥3 g a.i. PB. This effect still existed 2 years after treatment. Rates of ≤2 g per plant did not influence leaf area. Floral or vegetative bud development, photosynthesis, transpiration, or fruit size when measured 1 year after treatment, but fruit yields were inversely correlated to PB levels. Two years after application, ≤2 g rates had not influenced total plant growth. Stems arising from mature canes were reduced by ≥ 0.5 g PB, but length of juvenile canes was increased by rates up to 2 g PB. Paclobutrazol applications had no influence on leaf content of N, P, Ca, Mg, Fe, or Cu. Only the highest level resulted in increased leaf levels of K and Zn, but Mn leaf content was increased by all levels of PB. In general, rates of soil-applied PB which reduced vegetative growth also reduced fruit yield. Chemical name used: β [(4-chlorophenyl)methyl]-α-(1,1 dimethylethyl)-1H-1,2,4-triazole-l-ethanol (paclobutrazol).

Open Access
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A sand culture study arranged in a 3 × 3 factorial was used to determine the influence of Al and Mn levels on leaf nutrient content and plant growth of `Tifblue' rabbiteye blueberry (Vaccinium ashei Reade). Aluminum fertilization increased leaf Al content but did not affect plant vigor, leaf dry weight, or chlorosis. Manganese fertilization resulted in increased Mn in the leaves and a decrease in all growth parameters measured. The Al × Mn interactions were significant for Mn concentration in the leaves and vigor ratings. At the highest Mn fertilization rate, increasing Al fertilization had a synergistic influence on leaf Mn. Plant vigor at the highest Mn rate was lowest when no Al fertilizer was added. Increasing Al fertilization resulted in better plant vigor in plants grown with a high rate of Mn fertilization.

Free access
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In a sand culture study, increasing Na levels increased leaf concentration of Na, Mg, Ca, Mn, and Zn, and reduced leaf K and plant dry weight. Magnesium fertilization did not affect leaf concentration of Ca, K, Mn, Fe, or Zn. High Ca fertilization increased leaf Ca. At high Mg levels, Ca fertilization had a synergistic influence on Mg uptake. Ca and Mg fertilization did not independently influence plant vigor, chlorosis symptoms, or dry weight production of leaves and stems. As levels of Na fertilization increased, plant vigor and leaf production decreased and chlorosis symptoms increased. With low Na fertilization levels, high Mg fertilization reduced leaf production but with high Na fertilization, plants receiving high Mg levels produced twice the weight of leaves as those with low Mg fertilization. High Mg fertilization reduced the detrimental effects of high Na fertilization on plant growth. This effect may be due to the antagonistic influence of Mg fertilization on Na uptake at high Na fertilization levels.

Free access
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The effects of varying rates of a complete fertilizer and irrigation on the growth and fruit yields of `Tifblue' rabbiteye blueberries (Vaccinium ashei Reade) established 3 years before treatment initiation were determined in a field study. Increased rates of irrigation resulted in increased plant growth and fruit yields. Five- and 6-year-old plants were more responsive to increasing irrigation rates than older plants. Irrigation water efficacy was greatest at lower rates and progressively less at higher rates of irrigation. Five- and 6-year-old plants fertilized with the lowest rate (14N–4P–7K; 150 g/plant) grew and yielded less than those fertilized with higher rates. Older plants did not respond to fertilization rates higher than 150 g/plant. Yearly rates of fertilization above 300 g/plant did not influence plant growth or fruit yields. Fertilization and irrigation responses were independent.

Free access