George E. Fitzpatrick

Immature Compost Suppresses Weed Growth Under Greenhouse Conditions

The influence of immature municipal solid waste-biosolids composts on emergence and mean days to emergence (MDE) of several weed species was evaluated in a pot trial under greenhouse conditions. The experiment consisted of placing a 7.5 cm deep layer of three-day-old immature compost, a mature and stable compost, an artificial medium or control sand as a mulch on ivyleaf morning glory seeds. Immature three-day-old compost decreased percentage emergence, shoot and root dry weight, and increased MDE of ivyleaf morning glory. In an experiment with eight-week-old immature compost utilizing mulching depths of 2.5, 5, 7.5, 10 cm and the untreated control on seeds of three weed species, common purslane did not emerge under any of the immature compost treatments. The MDE of ivyleaf morning glory and barnyard grass increased linearly as immature compost depths increased. Next, eight economically important weed species were sown in pots with either mature or immature (eight-week-old) compost utilizing mulching depths of 2.5 and 10 cm, in addition to an untreated control. Control pots yielded higher percentages of emergence than compost treatments for all species evaluated. Common purslane, large crabgrass, pig-weed, Florida beggarweed, and dichondra did not emerge through a 10-cm deep layer of mature compost mulch, or 2.5 or 10 cm deep layer of immature mulch. Significant compost maturity/depth interactions were observed for percent emergence on common purslane, ground cherry, large crabgrass, Florida beggarweed, and ivyleaf morning glory. A thinner layer was required to suppress germination using immature eight-week-old compost as compared to mature and stable compost. Immature (three-day or eight-week-old) compost containing acetic acid concentrations of 2474 and 1776 mg.kg−1 respectively reduced percentage emergence of several economically important weed species. These studies suggest that immature composts can be used to control weeds under conditions where spatial separation is maintained between the crop and the compost and phytotoxic fermentation products do not affect the health of the mulched plants and where odors associated with such partially stabilized products do not pose problems.

Growth of Impatiens ‘Accent Red’ In Three Compost Products

Growth of Impatiens wallerana Hook. ‘Accent Red’ was evaluated in three composted urban waste materials (composted biosolids and yard trash (SYT): 20 percent biosolids/sewage sludge, 44 percent yard trimmings, and 36 percent mixed paper; composted refuse fuel residues with biosolids and yard trash (RYT): 74 percent refuse-derived fuel residuals, 10 percent biosolids/sewage sludge, and 16 percent yard trimmings; and composted municipal solid waste (MSW): 100 percent municipal solid waste). Treatments consisted of 100 percent composted waste and media in which the composted wastes were combined with control medium components at 60 percent, 30 percent, or 0 percent composted waste, by volume. Shoot dry mass of plants grown in SYT increased as the percentage of SYT in the medium increased, while shoot dry mass of plants grown in MSW linearly decreased from 1.24 g to 0.15 g. There were no significant differences in shoot dry mass of plants grown in different percentages of RYT. Initial medium soluble salt conc...

A Program for Determining Cocompost Blending Ratios

▪ A program is presented that computes blending ratios for two ingredients of a co-compost. The program is written in the RPN language, requires 61 lines of memory, and will support hand-held programmable calculators, making it suitable for use in the field. Use of this program allows the composter to determine blending ratios quickly and with increased precision and accuracy.

A review of the impact of roadway vegetation on drivers’ health and well-being and the risks associated with single-vehicle crashes

Abstract Roadside trees can help calm traffic, define roadways and reduce drivers’ stress. However, roadside trees are also one of the most common components of urban infrastructure involved in single-vehicle crashes. The aim of this review is to identify and summarise research findings on risk assessment for tree crashes and the effect of roadside vegetation on drivers’ psychology and behaviour. The literature was obtained by entering keywords into multiple search engines and tracking down references that were cited in articles that were on-point. This literature review summarises findings from road safety research, identifying trends in tree and site factors that have been used to model single car crash frequency and severity. In looking at 10 similar studies, 8 found that the location of a tree (i.e. distance from the roadway) was a significant predictor of crash likelihood or severity. Other recurring predictors of tree-related car crashes include time of day and roadway geometry (e.g. the presence of a curve). In addition, this literature review summarises findings from road safety research regarding drivers’ perception of trees in the streetscape and the impact that roadside vegetation has on drivers’ behaviour and psychology. Generally, roadside vegetation had a positive psychological effect on drivers, in that it reduced drivers’ stress and frustration, and was also correlated with reduced driving speeds.

Drivers’ risk perception of roadside trees

ABSTRACT Roadside trees can help calm traffic, define roadways, and reduce driver stress. However, roadside trees are also one of the most common components of urban infrastructure involved in single-vehicle crashes. The authors used conjoint analysis to assess driver perceptions of risk associated with roadside trees, road geometry, vehicle speed, and lighting conditions. Florida drivers were shown videos depicting street scenes with randomised variations of these four attributes and were asked to rate their perceived risk. Results indicate that drivers perceived trees in close proximity to roadways as increasing risk and night-time conditions with supplemental lighting as slightly reducing risk. Overall, lighting condition was the most important attribute driving risk ratings, followed (in order of importance) by car speed, tree proximity, and road geometry.

Programs for Improved Compost Rate Calibration

Compost rate calibration procedures using programmable calculators improve the precision and accuracy of compost application. Two programs, one for English system units of measure and the second for the Metric system, are presented. Both are written in the RPN programming language and support hand-held, portable, programmable calculators, making them suitable for use in the field. Both require inputs of area to be covered and depth of coverage and compute volume of compost required for the specified coverage.