Search Results

Although composting has been practiced for thousands of years, it was not until the 20th century that controlled scientific studies were published illustrating the benefits of compost use in crop production. These studies helped to spur increased interest in composting and compost use, and gave way to the development of commercial composting facilities that supply finished compost products to horticultural producers. Increasing composting activity and compost use encouraged the formation in the late 20th century of trade organizations, such as the U.S. Composting Council and similar organizations in other countries, that support research and applications work to determine ways to improve quality control of commercial compost products.

Traditional N mineralization studies have been conducted by soil scientists using soils and temperatures found in field production. As temperature, in part, governs the rate of mineralization, and container substrates reach much higher temperatures than do soils, the effect of these elevated temperatures on mineralization must be considered to begin to understand N mineralization in container substrates during production. The N mineralization patterns of three composts [turkey (Meleagris gallopavo) litter, yard waste, and municipal waste] were determined under three temperature regimes (45, 25, and 45/25 °C). More organic N was mineralized from composted turkey litter (CTL) than from municipal or yard composts, regardless of temperature. The percentage of organic N mineralized from CTL was greater at 45/25 and 45 °C than at 25 °C.

A study was conducted on the Texas A&M Univ.-Commerce campus to evaluate the effect of compost type on the spread of bermudagrass into rose garden beds. Roses were planted in an randomized complete-block design in beds amended with composts derived from yard waste, manure, poultry litter, or dairy manure, or an unamended control. The study site was free of vegetation prior to planting. No pre- or post-emergent herbicides were applied after planting. Each bed was assessed visually monthly and scored on a scale of 0 to 10, with each point equivalent to 10% coverage. A bed received a score of 10 upon full coverage. Beds amended with poultry litter and yard waste had significantly higher bermudagrass invasion and reached 100% coverage more quickly than other treatments. Some of the poultry litter beds reached 100% coverage within 40 days of planting. The control planting had significantly lower coverage than all compost treatments throughout the study.

Abstract

Parthenocarpic cucumber (Cucumis sativus L. ‘La Reine’) plants were grown in the greenhouse in containers filled with equal parts by volume of peatmoss and vermiculite blended with 0%, 25%, or 50% by volume compost made from ferric-chloride-precipitated, lime-stabilized, digested sewage sludge composted with wood-chips and amended with various rates of sulfur. The Cd concentration of leaf and fruit samples from plants grown in media amended with 25% or 50% compost and S at 0, 10, 20, or 40 g·liter^–1 was unaffected by changes in pH from 7.2 to 3.4. However, Zn concentration in fruit samples from plants grown in media amended with 25% compost and S at 40 g·liter^–1 increased relative to other rates of S, whereas Zn concentration of leaf tissue was unaffected by rate of S application. Yield of fruit was not significantly affected by any of the treatments. Cucumber plants can be grown successfully in media amended with as much as 50% composted sewage sludge low in heavy metal content and over a wide range of pH values without the accumulation of fruit Cd levels hazardous to human health.

Compost has great potential for use in horticulture; however, the relationship between compost feedstock materials and resultant compost characteristics must be well understood. Research examining plant growth response from the addition of compost to container growing media is limited. This research had two parts: the first part examined the relationship between compost feedstock materials and resultant mature compost characteristics. The second part investigated plant growth responses when compost replaced the peat component of container growing media. Two feedstock treatments were aerobically composted in turned windrows. Compost characteristics examined include pH, EC, C:N Ratio, Solvita Maturity, and several biological characteristics (total and active bacteria, total and active fungi, protozoa, spore forming bacteria, E. coli O157:H7, and total coliformic bacteria). To examine plant growth response, compost was substituted for peat (from 0%-40% by total volume) in container growing media. Crops tested were Antirrhinum majus `Rocket White', Viola × wittrockiana `Crown Azure', Oriental Hybrid Lilium `Siberia', and Chrysanthemum × grandiflorum `Yellow Kodiak'. Quantitative plant growth response measurements (shoot fresh and dry weight, percent root necrosis, flower number, and flower size) were recorded and compared by treatment. Despite initial feedstock differences between the two compost treatments, both resulted in similar compost biology and species richness. Coliformic bacteria and E. coli O157:H7 levels were below detection limits in final compost. Choice of compost feedstock materials had a significant effect on the chemical characteristics of the finished product. Compost replacement for peat resulted in plant growth greater than or equal to those of the control treatment.