increased carbon oxygen demand and polyphenol content ( Ehaliotis et al., 1999 ). Several techniques such as evaporation, coagulation and flocculation, chemical oxidation, biological treatments with fungi and bacteria, and composting have been used to
Nikolaos Ntoulas, Panayiotis A. Nektarios and Glykeria Gogoula
John L. Cisar and George H. Snyder
The objective of this experiment was to determine the suitability of a compost obtained from a commercially available solid-waste processing plant for sod production when placed over a plastic barrier. Comparisons were made between compost-grown sod with and without fertilizer and between compost-grown sod and commercially grown sod. Six weeks after seeding or sprigging, both fertilized and nonfertilized compost-grown `Argentine' bahiagrass (Paspalum notatum Flugge), `Tifway' bermudagrass (Cynodon transvaalensis × C. dactylon), and `Floratam' St. Augustinegrass [Stenotaphrum secundatum (Walt.) Kuntze.] had discolored leaf blade tissue and poor growth. At 6 weeks, bahiagrass leaf tissue had a low N concentration, which suggested that the compost immobilized fertilizer N. Additionally, initial high salinity of the compost (2.85 dS·m-1) may have contributed to turf discoloration and lack of vigor. However, poor growth and discoloration were temporary. At 3 and 5 months, fertilized compost-grown turfgrasses had higher quality and coverage than nonfertilized sod. At 5 months, fertilized sod had sufficient coverage for harvest, whereas for conventional field production 9 to 24 months generally is required to produce a harvestable product. Compost-grown sod pieces had similar or higher tear resistance than commercially grown sod. One and 3 weeks after transplanting on a sand soil, compost-grown sod produced higher root weight and longer roots in the underlying soil than did commercially grown sod. The solid-waste compost used in this study offers a viable alternative material for producing sod that will benefit solid-waste recycling efforts.
Allen V. Barker and Tara A. O'Brien
An agricultural compost of chicken manure and cranberry pomace, a municipal compost of biosolids and mixed municipal solid wastes, and a compost of autumn leaves were evaluated for production of turfgrass sods and wildflower sods. Composts made during the year of the experiment and one-year-old composts were compared. The experiment was conducted outdoors with composts layered on sheets of plastic laid on the soil surface. The sheets of plastic controlled soil-borne weeds and facilitated harvest of sods. The best sods measured by stand and growth were produced with the agricultural compost, which was rich in N (avg. 1.7%) and low in NH4+ (avg. 135 mg/kg). High NH4+ (>900 mg/kg) appeared to limit stand establishment with the fresh municipal compost. The leaf compost was too low in N to support sod growth without fertilization. Aging of each compost improved its capacity to support sod production, apparently as a result of changes in the N status in the media.
Richard H. Zimmerman
Highbush blueberry is adapted to well-drained sandy soils containing some organic matter, but these are often unavailable in many areas where blueberry production is desired. I tested the concept of using freely available by-products to produce an artificial medium for growing blueberries. In June 1997, 1-year-old tissue-cultured plants of `Bluecrop' and `Sierra' blueberry were planted into 15-L plastic pots filled with soil or soilless medium in a total of 10 treatments. Soils used were Berryland sand (alone) and Manor clay loam (alone or amended with 25% or 50% compost mix 1); soilless media were composed of coal ash amended with 25% municipal biosolid compost (B), 25% leaf compost (L), 25% or 50% compost mix 1 (1 B: 1 L),\ or 25% or 50% compost mix 2 (1 compost mix 1: 1 acid peatmoss). pH of all mixes containing compost was adjusted to ≈4.5 with sulfur. After the first year, plants of both cultivars in Berryland sand had significantly more shoot growth than in any other treatment except for Manor clay loam. The least growth was produced by plants growing in Manor clay loam amended with compost mix 1 and in coal ash amended with unblended compost (B or L). After the second year, plants in the best treatments were 90 to 100 cm tall. More shoot growth was produced by plants in Berryland sand and in coal ash amended with 25% or 50% of compost mix 1, followed by plants in coal ash amended with 50% compost mix 2 or 25% compost B; plants in Manor clay loam, whether or not amended with compost, had the least growth. In 1998, 95% of the plants flowered and most set fruit, but differences among treatments were not significant. `Sierra' plants produced more growth than those of `Bluecrop' in all treatments.
Calvin Chong and Peter Purvis
Plug-rooted liners of deutzia (Deutzia gracilis), dogwood (Cornus alba `Argenteo-marginata'), forsythia (Forsythia×intermedia `Lynwood Gold'), and ninebark (Physocarpus opulifolius) were grown in 6-L containers. There were 36 different treatment substrates formulated in factorial combinations: two types of paper mill sludge (raw or composted) each at three rates (25%, 33%, or 50%, by volume) mixed with one of three sources of municipal waste compost (cities of Guelph, Toronto, or Waterloo; 25%, 33%, or 50%), and the remainder consisting of one of two base supplements (pine bark or 1-year-old wood chips; 50%, 33%, or 0%). The containers were trickle-irrigated and fertilized with a controlled-release fertilizer. Dogwood (no treatment interaction and responding only to the main effect of compost sources) grew equally well with Toronto and Waterloo composts, but less well with the Guelph compost. Ninebark tended to grow better with Toronto compost, intermediate or similar with Waterloo compost, and least with Guelph compost. Forsythia grew equally well in all bark-based substrates, regardless of sludge type and rate or compost source. With wood-chip-based substrates, however, forsythia grew better with Waterloo than with Guelph compost, and better with raw than with composted sludge when mixed with Toronto compost. Deutzia responded similarly to most substrates, but grew marginally better with raw than with composted paper sludge when Waterloo or Toronto compost was present. Despite these differences in species responses, all plants were of marketable size at the end of the season. There was no sign of nutrient toxicity or deficiency due to any of the substrates.
N.E. Roe and S.R. Kostewicz
Nitrogen additions to high C:N yard wastes improve the composting process and the usefulness of the product. Nine composts were made with additions of 10 or 25% grass clippings or poultry manure (PM) and several composting methods (in bin, turned, static). Turnip, tomato, watermelon, snap bean, and lettuce seeds were germinated, and some were grown to maturity in pots. The 25% PM compost delayed germination of turnips and beans by 2 days, but final germination % was not affected. Germination of melon (27%) was significantly less with 25% PM than with other composts. Tomato germination was not affected by any treatment, but dry weight of 4 week old seedlings grown in PM treatments was 4 times greater than other treatments. Pod yield of beans grown in 10% PM compost was equal to beans grown in potting mix with soluble fertilizer.
Kimberly A. Klock-Moore and George E. Fitzpatrick
Analytical determination and confirmation of minimum compost processing times and minimum curing times can aid commercial growers in selecting compost materials that should give them more reliable and consistent results in their operations. Five-cubic-yard volumes of yard-trimmings were assembled into three 1.25-cubic-yard compost piles at 60-day intervals. At the conclusion of the experiment, there were three piles each of compost of the following ages: 10 months, 8 months, 6 months, and 2 months. Compost was collected from each pile and screened through a 0.75-inch screen. Bulk density, water-holding capacity, air-filled porosity, carbon to nitrogen ratio, electrical conductivity, and ATPase activity were determined on samples from each reference compost pile. A bioassay using beans also was performed. These data will be presented.
Otho S. Wells and James R. Mitchell
In 1992 and 1993, a run-down, infertile field was treated with 0, 12, 24, and 48 T/A (day weight) of compost. Timothy was grown on the plots each year and removed. In 1994 and 1995, `Earliqueen' muskmelon was grown in the same plots, along with four types of synthetic mulch (black plastic, IRT-100 plastic, IRT-200 plastic, and paper). Over the two years, there was a consistent crop response. As compost rates increased, crop yield increased. The highest yields were with the higher rates of compost coupled with the IRT mulches. After 2 years of cropping, the soil nutrient status remained at acceptable levels at the 24 and 48 T/A rates of compost. Generally, organic matter, pH, and CEC increased with increasing compost rates. Foliar diseases were suppressed with the compost at all rates.
Otho S. Wells and James R. Mitchell
For 2 successive years, compost at rates of 0, 12, 24, and 48 t/acre were applied to a previously highly infertile field. Timothy was grown and harvested for these 2 years. Subsequently, for 3 consecutive years, through 1996, `Earliqueen' muskmelons were grown in the same plots without any additional compost being added. Subplots consisted of plastic and paper mulch and bare soil. Yields increased with increasing rates of compost for each of the 3 years, although yields for all treatments declined in the 3rd year. Highest yields were with the higher rates of compost coupled with IRT mulches and red mulch. Generally, organic matter and pH increased with increasing compost rates. Foliar diseases were suppressed with compost; however, there was an interaction of suppression with plastic mulches.
Catherine S.M. Ku and John C. Bouwkamp
Blending compost from various feedstocks may increase the beneficial effects of compost as potting substrate. A factorial treatment combinations included 10 compost combinations, Sunshine Mix and Pro Gro 300S as controls, three compost levels, and three chrysanthemum cultivars. The compost combinations were Compro (CP), poultry litter (PL), PSG polymer dewatered biosolids (PSG), yard trimmings (YT), CP:PL, CP:PSG, CP:YT, PL:PSG, PL:YT, and PSG:YT; all blends were on a 1:1 ratio (v/v). The compost levels were 50%, 75%, 100%; and chrysanthemum cultivars included `Boaldi', `Cherry Davis', and `Yellow Favor'. All treatments were replicated six times. Plants were fertilized with 100 mg/L N from 20N–8.8P–16.6K twice weekly. All compost substrates, except PSG blends produced plants that were shorter than the controls. All compost blends produced similar or greater number of flower than the controls. Plants grown in substrates containing PSG and/or CP produced dark green or green foliages, and other substrates produced plants with pale green leaves. The PSG:PL and PSG: YT blends produced premium-quality plants. All other compost blends produced good-quality plants that were similar to the controls.