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Abstract

This study was conducted to determine the availability of N from urea applied to a pine bark container medium. Results showed that negligible amounts of urea are adsorbed to a pine bark medium compared to NH4-N. However, 71% of the urea applied was hydrolyzed to NH4 within 24 hr and 95% within 40 hr. The rapid hydrolysis would allow N from urea to be available for plant uptake or adsorption to bark soon after application, making urea an acceptable source of N for a pine bark medium.

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Beginning in the early 1970s, the search for organic soilless substrates for container production has been an important horticultural research topic with the introduction of hardwood and softwood barks as the primary component in nursery container

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-only management strategy, there is a need for integrated and sustainable weed management strategies. The primary component of container nursery substrate consists of pine ( Pinus sp.) bark, comprising 60% to 80% of most substrate mix ( Lu et al., 2006 ). This

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Grapevine (Vitis vinifera L.) explant shoots indexed forcorky-bark and rootstocks from healthy LN33 indicator plants were sterilized and maintained in vitro. When infected shoot tips were micrografted onto LN33 shoots, typical corky-bark symptoms appeared in 8 to 12 weeks. We suggest developing this method further to replace the regular, 2-year indexing procedure.

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diffusion across concentration gradients, and the interaction with bark particle exchange sites ( Hoskins et al., 2014a ). Therefore, biochar may influence nutrients leaching from a soilless substrate. Biochar can have a substantial impact on the release and

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Abstract

The pistachio (Pistacia vera L.), characteristically a biennial bearer, produces its most extensive shoot growth in years of heavy crop production. Whereas levels of total sugars in bark and wood of bearing and nonbearing branches were similar throughout the year, starch levels tended generally to be higher in nonbearing than in bearing branches. Consequently, nonbearing branches one year gave rise to heavy crops the next and, beacuse of greater quantities of reserve foods, also produced extensive shoot growth. Bearing branches of that same year, .however, produced few or no nuts the next and, because of lesser quantities of reserve foods, produced markedly less shoot growth. No relationship between total nitrogen level and shoot growth or fruiting was evident.

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The use of shredded bark, wood chips, and other organic mulches to conserve water and moderate soil temperatures is a common practice in landscape maintenance. Four mulch materials (cottonseed hulls, cypress pulp, pine bark, and pine straw) were examined to determine effects on plant growth and soil conditions in annual flower beds during a 1-year rotation of warm season to cool season annuals. Inhibited plant growth was observed in pine bark treatments at the conclusion of the growing season for both plantings. Effects on soil conditions were insignificant over the year-long study in pine bark treatments. To further investigate potential phytotoxic effects of pine bark and other mulch used in the initial study, a seed bioassay was performed to determine the influence of mulch extracts in solution on germination and primary root elongation.

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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.

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Abstract

Coal cinders with pine bark were evaluated as containerized plant growing medium. Rhododendron obtusum Lindl. ‘Hinodegiri’ liners were grown in several combinations of media composed of pine bark mixed with an aged and a recently combusted source of cinders. Measurements of media pH, soluble salts, NO3 –N, NH4 + –N, and 19 extractable nutrient and metallic ions were obtained. Leaf tissue samples were analyzed for 19 elements. Top dry weight, visual growth and chlorosis ratings, and root visual ratings constituted the plant growth parameters measured. Satisfactory growth was generated in pine bark amended with up to 50% cinders from either source.

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Authors: and

Abstract

Initial availability of NO3, NH4, and urea applied to limed or unlimed pine bark as well as the form of N available over a period of 21 days was determined. Nitrate was not present in significant amounts when N was supplied as either urea or NH4, and the extractable amounts of both urea and NH4 declined significantly over the course of the experiment. Urea was the least effective of the N forms in supplying N in an extractable form. With NO3 as the N source, addition of lime to pine bark resulted in significant reductions in extractable NO3. Applications of NH4 gave relatively equal amounts of extractable N as NH4 from limed and unlimed pine bark after 21 days. It was concluded that N interaction and N transformations with these N forms in pine bark would influence total available N as well as the form of N available for plant growth.

Open Access