Pine Bark Media Research Articles

Effect of Liming Rate on Nitrification in a Pine Bark Medium

Abstract A 100% pine bark medium was amended with dolomitic lime at 0, 3, or 6 kg·m−3 and periodically fertilized with 210 ml of a nutrient solution containing 100 ppm N as (NH4)2S04. At the 3- and 6-kg lime treatments, medium solution NH4-N concentrations decreased rapidly while N03-N concentrations increased. At 0 kg lime, the NH4-N decrease was slower than at the 3- and 6-kg lime treatments and N03-N was not found. Similarly treated bark without plants was used to determine a N03-N accumulation rate (NAR). NAR was greatest at 6 kg of lime, except at the last 2 sampling dates, when NAR did not differ between 3 and 6 kg of lime. This lack of difference was attributed to a limiting NH4-N supply at 6 kg of lime. In a 2nd experiment, NAR of bark treated with 6 kg of lime per m3 and fertilized with 300 ppm NH4-N was 3 times greater than with bark treated with 100 ppm NH4-N, thus supporting the contention that, over time, the NH4-N supply of the 100-ppm treatment limited nitrification. These results indicate that the stimulative influence of lime on nitrification is subject to medium pH and NH4-N status that changes over time.

The Influence of Nitrification on the Medium Solution and Growth of Holly, Azalea, and Juniper in a Pine Bark Medium

Abstract Three genera of woody plants were container-grown in a pine bark medium. Pine bark was amended or unamended with nitrapyrin (NI) and fertilized with an NH4-N fertilizer. Medium solution NH4-N concentrations of bark without NI decreased rapidly for the first 3 to 5 weeks with a concomitant increase in NO3-N concentrations. Medium solution pH at 0 NI decreased 0.8 unit during periods of rapid NO3-N accumulation. The low medium solution pH of the 0 NI treatment resulted in solution Ca, Mg, and Mn concentrations that were several times greater than at 82 μg of NI. Correspondingly, tissue concentrations of these ions were generally greater at the 0 NI treatment than at the 82 μg NI treatment. In general, there were no differences in shoot dry weight in response to NI treatment. Results indicate that nitrification is important in the nutrition of container-grown plants.

Mite Control, 1985

Abstract Infested variegated liriope growing in 1-gal containers of an amended pine bark medium were selected for the foliar treatments listed. Miticides plus Chevron Spray Sticker (0.5 pt/100 gal water) were applied to all leaf surfaces to run-off with a hand-pumped, compressed air sprayer. Four single-plant replicates were arranged in a completely randomized design. Live mites were counted 7 and 21 days after treatment with the aid of a Llanfair Orchard Leaf Brushing Machine and microscope. Each sample consisted of 3 randomly selected mature leaves per plant.

Citrus Whitefly Control, Alabama, 1985

Abstract Test plants were ca. 1 ft tall, growing in 3-qt plastic pots filled with an amended pine bark medium. Fourteen insecticides were applied by 1 or 2 methods: foliar sprays or insertion of fertilizer spikes impregnated with an insecticide into soil around plant. Treatments were replicated 4 times, one plant constituting a replication. A single application of the test materials was made out-of-doors on 17 Jun (Dry Bulb 86°F: Wet Bulb 78°F). The adjuvant Nu-Film 17 was added to all spray mixtures at the rate of 2.4 ml/gal. Foliar sprays were applied to runoff using a hand-pumped compressed air sprayer and spikes were placed ½ inch below soil surface, 1 inch from pot rim, and watered in. Test plants were returned to a screened shadehouse. Efficacy was determined 1 Jul by examining 100 citrus whitefly pupae per plant and scoring them as dead or alive.

Florida Wax Scale Control, 1985

Abstract Infested Burford holly growing in 1-gal containers of an amended pine bark medium were selected for treatments listed. Insecticides plus Nu-Film 17 (0.5 pt/100 gal water) were applied to all leaf surfaces until run-off with a hand-pumped, compressed air sprayer. Four single-plant replicates were arranged in a completely randomized design. Twenty-one days after treatment, percent mortality was determined by examining 100 scales per plant using a probe and microscope.

Florida Wax Scale Control, 1985

Abstract Plants were growing in 1-gal containers of an amended pine bark medium. Jobe’s Plant Food Spikes impregnated with an insecticide and checks were uniformly placed 0.5 inch below the soil surface, 1 inch from pot rim. In the two-spike treatments spikes were placed directly opposite each other in the pot. Treatments were replicated, completely randomized, and maintained in an unshaded glass greenhouse. Percent mortality was determined by examining 100 scales per plant using a probe and microscope.

Boxleaf Euonymus, Euonymus Scale Control Using Trunk Paints, 1984

Abstract Paint-on treatments were compared to foliar application of Cygon 2E for control of euonymus scale. Sixteen 1-1.5-ft-tall boxleaf euonymus, heavily infested with euonymus scale, were selected for treatment. Test plants were growing in a pine bark media in 2-gal black plastic pots. Cygon 2E was applied as a paint-on band treatment to the trunk of the plant at the rate of 1 inch band per inch of trunk diameter. The material was applied with a sponge paint brush by dipping the brush in full strength Cygon 2E and painting the appropriate size band of insecticide around the trunk of the plant. To test for phytotoxicity, an additional group of plants were treated at twice the test rate. Foliar sprays were applied to runoff using compressed air sprayers. Care was taken to spray the underside of the foliage to provide optimum contact of the insecticide with target pests. Four replicates (plants) were used per treatment. Treatments were applied 11 Nov ‘83. Efficacy of the treatments was evaluated 19 Mar ‘84, by examining 100 adult female euonymus scales per replicate and scoring them as living if normally colored and full bodied or dead if discolored and shriveled or dried.

Boxleaf Euonymus, Hemispherical Scale Control 1984

Abstract Twelve 1-1.5-ft-tall boxleaf euonymus, heavily infested with hemispherical scale, were selected for treatment. Greenhouse grown test plants were in a pine bark media in 2-gal black plastic pots in a completely random arrangement spaced evenly on a 4 X 9.5-ft table. Test materials were applied 20 Sep with hand-pumped, compressed-air sprayers. Test plants were removed from the greenhouse and all foliage was sprayed to runoff. When plants had dried, they were returned to the greenhouse. Treatments were replicated 3 times with each plant constituting 1 replication. Mortality counts were made by examining 100 scales per replicate 27 Sept under a stereomicroscope and scoring each scale as living if normally colored and full bodied or dead if discolored and shriveled or dried.

Citrus Whitefly Control, Alabama, 1983

Abstract Severely infested gardenia growing in 2-gal pots filled with an amended pine bark medium were selected for treatments. Materials were applied to all leaf surfaces until run-off with hand-pumped, compressed air sprayers. Four single-plant replicates were arranged in a completely randomized design. Whitefly nymph mortality was determined 14 and 32 days after treatment.

Influence of Liming Rate on Holly, Azalea, and Juniper Growth in Pine Bark

Abstract Rooted cuttings of Ilex crenata Thunb. ‘Helleri’, Rhododendron obtusum Planch. ‘Rosebud’, and Juniperus chinensis L. ‘San Jose’ were grown in a 100% pine-bark medium amended with dolomitic limestone at 0 to 8 kg m-3 with resulting pH from 3.4 to 7.2. Except for juniper at 2 kg m-3, growth was not increased by liming, and 8 kg m-3 tended to reduce shoot and root growth. This reduced growth was attributed in part to greater NH4 adsorption by the bark, reducing the amount available for plant uptake, and a higher nitrification rate, leading to an elevated NO3 to NH4 ratio in the medium. Liming pine bark to improve growth of these woody plants may be unnecessary.

Ammonium Adsorption on a Pine-bark Growing Medium

Abstract Pine bark was shown to adsorb 1.5 mg of N/g of bark when NH4 solutions were leached through the bark. Increasing pH of bark increased adsorbed NH4. At pH 3.3, only NH4 was adsorbed to bark particles when a fertilizer solution containing NH4, Ca, K, and Mg was applied. However, adsorption of NH4 and other cations increased as pH was increased from 3.8 to 5.8. These data indicate that 2 types of sites exist for the adsorption of NH4 to pine bark. One site is effective at lower pH; the other is active as pH increases. Daily application of 2.5 cm of water containing 50 ppm NH4 required 20 days for equilibration to occur so as to satisfy all binding sites. Thus, incorporation of NH4 into a pine-bark medium prior to planting may be advisable to prevent low N levels from occurring in the container solution due to NH4 binding when plants are first planted and fertilized.

Comparison of Pour-through and Saturated Pine Bark Extract N, P, K, and pH Levels1

Abstract The pour-through (PT) method of nutrient extraction, which involves pouring water on the container media surface and collecting the extract (leachate), was compared to the saturated soil extract (SSE) method for a 100% pine bark medium at container capacity (102% gravimetric moisture). The SSE and PT correlation coefficients, respectively, were 0.99 and 0.94 for N, 0.99 and 0.97 for P, 0.99 and 0.93 for K, and 0.99 and 0.98 for pH. As container media moisture levels increased from 50 to 102%, the PT and SSE soluble salt levels increased 1.5 and 1.6 times, respectively, while nitrate levels increased 1.7 and 1.6 times, respectively. The volume of water applied for the PT was varied from 40 to 100 ml and did not result in extraction of different levels of N, P, K, Ca, or Mg. These data indicate the PT is an alternative to the SSE for nutrient extraction from a pine bark medium.

Purple Passion Plant, Green Peach Aphid, 1982

Abstract Fenpropathrin and acephate (Orthene) were evaluated for aphid control on purple passion. Plants were grown in an amended pine bark medium in a glass greenhouse and hand irrigated as needed. Treatments were applied Apr 30 to all leaf surfaces to run-off with a hand-pumped, compressed air sprayer. At time of application, ambient temperature was 78°F with a relative humidity of 56%. Four single-plant replicates were arranged in a completely randomized design. Nu-Film 17, 8 oz/100 gal water, was added as an adjuvant to all insecticide treatments. Pretreatment and post-treatment counts were taken on tagged plant terminals.

Phytotoxicity Test on Container-Grown Woody Ornamentals, Alabama, 1982

Abstract Phytotoxicity of fenpropathrin 2.4EC was evaluated on 15 woody ornamentals produced in south Alabama. Plants were grown in an amended pine bark medium. F. japonica, M. bealei, R. X 'Coral Bell', R. X 'Mrs. G. G. Gerbing', and T. japonica were grown under 47% shade; other species in full sun. Overhead impulse sprinklers were used for irrigation. Treatments were applied to all leaf surfaces to run-off Apr 8, Apr 27, and May 11, at 0.075, 0 . 1 , and 0.4 lb ai/100 gal water with hand-pumped, compressed air sprayers. Phytotixicity evaluations were made 1 wk after each application and 4 wk after the last application. There were 5 single-plant replicates/species arranged in a completely randomized design.

Azalea Lace Bug Control, 'Gloria' Azalea, 1982

Abstract Fenpropathrin and acephate (Orthene) were evaluated for control of azalea lace bug on container-grown azaleas. Plants were grown in an amended pine bark medium under 50% shade and were hand irrigated as needed. Treatments were applied Apr 14 to all leaf surfaces to run-off with hand-pumped, compressed air sprayers. At time of application, ambient temperature was 83°F with a relative humidity of 55.5%. Four single-plant replicates were arranged in a completely randomized design. Nu-Film 17, 8 oz/100 gal water, was added as an adjuvant to all insecticide treatments. Counts were taken 1 and 7 days after treatment by brushing the canopy of an azalea held over a 8-1/2 × 11 in sheet of paper held in a clipboard.

DWARF Schefflera, Two-Spotted Spider Mite Control, 1982:

Abstract Fenpropathrin and Morestan were evaluated for spider mite control on dwarf schefflera. Plants were grown in an amended pine bark medium in a glass greenhouse and hand irrigated as needed. Treatments were applied Apr 26 to all leaf surfaces to run-off with hand-pumped, compressed air sprayers. At time of application ambient temperature was 80 F with a relative humidity of 55%. Four single-plant replicates were arranged in a completely randomized design. Nu-Film 17, 8 oz/100 gal water, was added as an adjuvant to all insecticide treatments. Counts were taken 1 and 7 days after application with a Llanfair Orchard leaf brushing machine.

Fertilization of cotoneaster in a pinebark medium

Cotoneaster dammeri C.K. Scheid. ‘Royal Beauty’ was grown at 2-N rates, 150 and 300 mg l −1, with NO 3-N, NH 4-N or a NH 4-N:NO 3-N combination, in a pinebark:sand medium (4:1 v/v). Plants grown with NO 3-N had greater shoot dry weight and tissue N concentration than plants treated with NH 4-N. Shoot growth was also greater with the higher N rate. Root growth was not affected by N source, but was increased by N rate.

Phosphorus Requirement of Ilex crenata Thunb. cv. Helleri Grown in a Pine Bark Medium1

Abstract Greenhouse-grown branched liners of ‘Helleri’ holly were fertilized with either 0, 5, 10, 15, 20, 25, or 30 ppm P to establish a P level in the pine bark medium that resulted in maximum shoot dry weight. Pine bark P levels greater than 10 ppm did not result in increased shoot dry weight. Total mg of P in shoot tissues continued to increase with P treatments higher than 10 ppm, indicating luxury consumption of P. Total mg of P in root tissues increased to the 5 ppm P treatment. Total μg of Mn in shoot tissues increased while total pg of Mn in root tissues decreased with increasing pine bark P levels. In a subsequent experiment, dry shoot weights of ‘Helleri’ holly grown in a pine bark medium amended with either 270, 540, or 810 g/m3 of P supplied as superphosphate (9% P) or fertilized with 10 ppm P were not different, while root dry weights decreased with increasing P amendment. Water extractable P for the 810 g/m3 treatment decreased 245 ppm during the experiment and by week 5 was below 10 ppm.

Ammonium Nitrogen Accumulation and Leaching from an All Pine Bark Medium1

Abstract When a 200 ppm N solution as (NH4)2SO4 was percolated through a wet pine bark medium, 6 times the medium volume of the N solution was required to reach an equilibrium of N in the bark. Once equilibrium was reached, the water added, leaching of the ammonium ion was rapid. When twice the medium volume of water was passed through the medium, 85% of the ammonium ions were leached. After analysis of the leachate indicated no N being leached from the bark, 60 ppm of N remained in the bark.

Response of Ilex crenata Thunb. cv. Helleri to Timed Fertilizer Applications1

Abstract Multiple branched liners of ‘Helleri’ holly growing in a pine bark medium were fertilized at the beginning of active root growth at 300, 400, 500, or 600 ppm N with a 20N−8.7P−16.7K water soluble fertilizer. One week later, one half of the plants were fertilized again. The treatments were repeated during the next 2 periods of root growth which occurred about 6 weeks apart. The above soluble fertilizer was applied weekly at 300 ppm N to the control plants. Shoot growth of plants fertilized twice at 500 ppm N was comparable to growth of the control plants. Further, these plants received 44% less fertilizer and utilized 17.6% more of the total fertilizer applied. Extract nutrient and soluble salt levels were high during root growth and low during shoot growth except for the control plants, indicating the plant's need for fertilizer predominates during periods of active root growth.