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Carleton B. Wood, Timothy J. Smalley, Mark Rieger, and David E. Radcliffe

Container-grown Viburnum plicatum Thunb. var. tomentosum (Thunb.) Miq. `Mariesii' were planted in unamended planting holes, tilled plots, and tilled plots amended with aged pine bark. A 36-day drought was initiated 108 days after planting. Amending induced N deficiencies, reduced shoot growth, and increased root growth. Plants harvested from tilled and planting-hole plots at drought initiation had 63% and 68% more dry weight, respectively, than plants from amended plots. Between 8 and 19 days after drought (DAD) initiation, plants from tilled plots maintained higher relative leaf water content (RLWC) than plants from planting holes. Plants in amended plots maintained higher RLWC than both other treatments between 7 and 33 DAD. Amended and tilled treatments had higher relative leaf expansion rates (RLERs) than the planting-hole treatment 8, 11, 13, and 15 DAD. As the drought lengthened, plants in amended plots maintained higher RLERs than plants in tilled plots. While plants in pine bark-amended plots were more drought tolerant than those in tilled plots, it is unclear if increased drought tolerance was caused by the improved rooting environment or N deficiency.

Open access

Alexander X. Niemiera and Robert D. Wright

Abstract

Nitrification in a pine bark medium in response to a range of applied NH4-N levels (25, 100, and 200 ppm) was studied. Medium solution NH4-N concentrations at the 25 ppm N treatment decreased from 30 ppm at day 1 to 0 ppm at day 40. Ammoniacal-N concentration values decreased from 64 to 6 ppm and from 105 to 20 ppm for the 100- and 200-ppm N treatments, respectively, by day 60. Rapid increases in medium solution NO3-N concentrations coincided with these NH4-N decreases, resulting in low medium solution NH4-N:NO3-N ratios. During the periods of NO3-N increase, medium solution pH decreased 0.3, 0.7, and 1.3 units for the 25-, 100-, and 200-ppm N treatments, respectively. Similarly treated bark without plants was used to determine a NO3-N accumulation rate (NAR). NAR data indicated that the NH4-N supply of the 100- and 200-ppm N treatments exceeded the oxidative capacity of nitrifiers during a 96-hr period.

Open access

T. H. Yeage, R. D. Wright, and S. J. Donohue

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.

Free access

Ramakrishna Nalagorla, Catherine Sabota, and Caula Beyl

Shiitake mushrooms contain lentinan, a polysaccharide that has numerous medicinal benefits. The objective of this research was to determine the impact of various rates of chipped and sawmill bark added to the substrate on lentinan found in shiitake mushrooms. Crude polysaccharide extract (CPE) and lentinan (LTN) content was significantly different among shiitake mushrooms grown on various artificial substrates containing different percentages of sawdust and chipped bark. The addition of chipped bark content from 0% to 50% increased the CPE content, but an increase in chipped bark content from 50% to 100% decreased the CPE and LTN content. CPE content in mushrooms was greater when equal proportions of sawdust and bark were used. A 100% heartwood treatment had the least CPE content.

Open access

P. A. Domoto and A. H. Thompson

Abstract

A greenhouse solution culture experiment was conducted to study the interactions of Ca, K and Mn supply on the concentration of 7 elements in bark tissues of ‘Delicious’ apple (Malus domestica Borkh) trees as related to internal bark necrosis (IBN). Under a regime of low Ca and high Mn, IBN symptoms developed late in the second growing season on the scion barks but not on the rootstock bark. Both the degree of severity and the incidence of the disorder increased with increasing K levels. Low Ca and high Mn concentrations in the barks are apparently necessary for the development of IBN, and under these conditions K affects the degree of severity. It is suggested that the higher K concentrations enhanced Mn toxicity by lowering the threshold for Mn-induced IBN, while Ca responded as a detoxifying agent. Low concentrations of B and P may contribute to IBN development, while Mg and Fe were not related to symptom development.

Open access

J. E. Klett and J. B. Gartner

Abstract

Total N content in the shoots of Chrysanthemum morifolium Ramat ‘Bright Golden Anne’ grown in hardwood bark was significantly greater when utilizing (NH4)2SO4 source of N than with KNO3 source. The NH4 + concn in the shoots was greatest at the low pH range when (NH4)2SO4 was the source of N. The NH4 + concn in the media was greatest at the low pH range when utilizing the (NH4)2SO4 and NH4NO3 sources of N.

The greatest dry wt of shoots was obtained if test plants were treated with both NH4 + and NO3 forms of N with NH4NO3 source of N at the higher pH range and without the nitrification inhibitor.

Open access

E. F. Brown and F. A. Pokorny

Abstract

Bulk density (BD) of potting media increased as the percentage of sand was increased in the medium. Because of the “fitting” together of particles, volume of medium mixtures was always less than the total volume of the separate components. Particle size distribution was determined most accurately on a volume basis and was used to identify the potting mixtures. The percentage of medium components (bark or sand) retained on any given sieve size could be determined from BD data. Percolation rate, and cation exchange capacity (CEC) declined as the percentage of sand was increased in the potting mixture. CEC was most accurately determined on a volume basis. Increasing the percentage of sand in the potting medium raised pH from 4.1 to 5.4.

Free access

William A. Hoch, Geunhwa Jung, and Brent H. McCown

A significant pest affecting commonly planted Betula spp. is the birch leafminer (Fenusa pusilla Lepeletier), an insect that can be present in large populations in the landscape and can greatly reduce the vigor and ornamental value of these trees. Twenty-two interspecific crosses were performed between leafminer resistant and susceptible Betula species in an attempt to create the novel combination of ornamental white bark and significant leafminer resistance. Of the nine successful crosses, two produced resistant offspring. Progeny of the diploid × hexaploid cross B. turkestanica Litvin (2x) × B. alleghaniensis Britt. (6x) displayed a broad range of resistance levels, likely the result of segregating alleles contributed by the hexaploid parent. All crosses involving highly resistant individuals of B. costata Trautv. (2x) yielded leafminer susceptible progeny. These results suggest that the larval antibiosis demonstrated by B. alleghaniensis and B. costata is inherited as a recessive trait, and exhibits a gene dosage effect as evidenced by the B. turkestanica × B. alleghaniensis offspring. While most progeny of the B. populifolia Marsh (2x) × B. maximowicziana Regal (2x) cross were susceptible, a single resistant offspring, which was found to be triploid (3x), displayed a mechanism of resistance similar to that of a hypersensitive response. No strong intersectional barriers to hybridization were observed and all interploidy crosses were successful. The chromosome numbers of B. costata (2n = 2x = 28) and B. turkestanica (2n = 2x = 28) are reported here for the first time. The results of this study indicate that the potential exists for the development of insect resistant, ornamental white-barked birch clones through the implementation of a planned, systematic breeding program.

Open access

Francis J. Regulski Jr.

Abstract

The physical and water-release characteristics of a gasifier residue in combination with bark, Canadian sphagnum peat, and sand were determined. Both gasifier residue and peat had characteristics more favorable for plant growth than bark or sand alone. The combination of gasifier residue and peat produced characteristics superior to gasifier residue or peat alone. Gasifier residue and combinations of gasifier residue and peat had almost twice the available water of a standard nursery medium. The addition of sand or bark decreased the performance of gasifier residue in a number of physical parameters. Unsieved gasifier residue had a particle size distribution suitable for container plant production.

Open access

R. B. Malek and J. B. Gartner

Abstract

Hardwood bark as a soil amendment for container-grown plants suppressed several species of parasitic nematodes in greenhouse tests. Volumetric bark to soil ratios of 4:1, 2:1, 1:1 and 1:2 greatly reduced incidence of root-knot caused by Meloidogyne hapla Chitwood and M. incognita (Kofoid and White) Chitwood on tomato (Lycopersicon esculentum Mill.). A 2:1 bark to soil mixture inhibited galling by M. incognita and population development of Pratylenchus penetrans (Cobb) Filipjev and Schuurmans Stekhoven and Trichodorus christiei Allen on Forsythia intermedia Zabel.