Coarse Bark Research Articles

Effect of two different thermal units and three types of mulch on weeds in apple orchards

The effect of two different thermal units (flame and hot steam) and three types of mulch on the percentage of weeds killed was studied in a series of experiments over 2 years. The factors studied were driving speed (2, 3, 4 km/h), flame treatment (first, second, third), growth stage (<6, 6–8, >8 true leaves), hot steam treatment (single, double), mulch type (none, coarse bark, sawdust, hay), and chemical application. The results suggest that a driving speed of 2 km/h kills the highest percentage of weeds, and for weed species with unprotected growth points and thin leaves, the first flame application can completely kill weeds with <6 leaves. However, a second or third flame application is required for those with 6 or more leaves. The hot steam method is effective when it is applied twice, with the second application 1 week after the first. However, there is room for improving its technology to make it cost effective for large-scale applications. Mulches after chemical herbicide application are effective for controlling weeds. However, mulching cannot be recommended with flaming because of fire hazard. The effectiveness of herbicide depends on the weed species and on whether the same herbicide was used in the preceding years. Compared to using herbicide with mulching, herbicide alone was less effective in controlling weeds and more costly in terms of cost per hectare and the environment. Key words: thermal weed control, flame, hot steam, mulching, herbicides, apple orchard, logit models.

A pilot-scale study on biofilters for controlling animal rendering process odours

Heating of animal tissue during the process of rendering liberates a variety of odorous compounds. The performance of biofiltration in removing these odours was investigated using pilot-scale biofilters containing different media (sand, finely and coarsely crushed wood bark, and bark/soil mixture). Odour-removal performance of the biofilters was determined using olfactometry. Biofilter odour removal efficiencies of between 29.7% and 99.9% were measured at influent odour concentrations of between 143,100 and 890,000 odour units m(-3), and various air loading rates (0.074-0.592 m(-3) air m(-3) medium min(-1)). Biofilters with bark or bark/soil media and low air loading rates gave the best odour removal. The bark and sand biofilters generally maintained good odour reduction for about three years at an air loading rate of 0.148 m(-3) air m(-3) medium min(-1). Drainage from the biofilters contained significant concentrations of nitrogenous and organic compounds, suggesting that controlled leaching has the potential to remove accumulated substances in biofilter media from rendering gas emissions and increase the longevity of a biofilter system. High pressure drop across biofilter media can adversely affect the odour removal performance. Sand and fine bark, due to their small particle size, caused high pressure drops. Coarse bark showed negligible pressure drop at several examined air loading rates. Pressure drop also increased with moisture content, particularly in sand and fine bark biofilters. Overall pressure drop characteristics of the biofilters described in this paper were maintained without significant change over the three year operation.

Growth of Azalea, [Rhododendron obtusum (Lindl). Planch. cv. Coral Bell] and Wax Myrtle [Myrica cerifera L.] as Affected by Capillary Watering, Media Type and Depth1

Abstract The avg wt increase of subirrigated dormant azalea tops after 75 days was 4.5g and of wax myrtle was 10.0g. The wax myrtle in a 30 cm deep perlite and peat medium produced the greatest fresh and dry wt which was twice as heavy as plants grown in a sand and bark medium. The peat, sand and soil and the peat and sand media produced the greatest new shoot number in azalea. The wax myrtle had greater shoot length in peat, sand and soil, and the per lite and peat media at 30cm depth, than in the peat and sand or the sand and coarse bark media. The azalea produced 5 shoots per plant which averaged 23cm in length, while wax myrtle produced 4 shoots with 41 cm in length. There was a decrease in soluble salt level and media pH but an increase in % media moisture with greater sampling depth from surface to bottom. Subirrigation may be beneficial for a wide variety of plants and cultural conditions since it provided a precise amount of water at all times.

Voice rehabilitation after laryngectomy.

THE IDEA of constructing a communication between the trachea and the pharynx in order to reestablish speech following total laryngectomy has undoubtedly occurred, at one time or another, to most laryngeal surgeons. Two complicating factors, however, have rendered any such procedure impractical—leakage of saliva and food into the trachea and ultimate stenosis of the tracheopharyngeal communication. In 1870 Professor Billroth performed a series of experimental laryngectomies on dogs. 1 He was successful in restoring a coarse bark by constructing a communication between the trachea and the pharynx. In 1874 Dr. Billroth performed the first recorded laryngectomy. Dr. Gussenbauer, a resident training with Dr. Billroth, designed and constructed an apparatus (Fig 1) for restoration of speech by way of a pharyngostoma above the tracheostoma. 2 In 1874 Czerny reported a series of dog experiments with restoration of bark, using a technique similar to that of Billroth's. 3 Scuri, in 1928, reported