Composting of municipal solid waste (MSW) has received renewed attention as a result of increasing waste disposal costs and the environmental concerns associated with using landfills. Sixteen MSW composting facilities are currently operating in the United States, with many more in the advanced stages of planning. A targeted end use of the compost is for horticultural crop production. At the present time, quality standards for MSW composts are lacking and need to be established. Elevated heavy metal concentrations in MSW compost have been reported; however, through proper sorting and recycling prior to composting, contamination by heavy metals can be reduced. Guidelines for safe metal concentrations and fecal pathogens in compost, based on sewage sludge research, are presented. The compost has been shown to be useful in horticultural crop production by improving soil physical properties, such as lowering bulk density and increasing water-holding capacity. The compost can supply essential nutrients to a limited extent; however, supplemental fertilizer, particularly N, is usually required. The compost has been used successfully as a sphagnum peat substitute for container media and as a seedbed for turf production. High soluble salts and B, often leading to phytotoxicity, are problems associated with the use of MSW compost. The primary limiting factor for the general use of MSW compost in horticultural crop production at present is the lack of consistent, high-quality compost.
Carl J. Rosen, Thomas R. Halbach, and Bert T. Swanson
Nancy E. Roe, Peter J. Stoffella, and Herbert H. Bryan
A mulch of municipal solid waste compost at 224 t·ha was compared with glyphosate sprays and a nontreated check for weed control in vegetable crop bed alleys during Spring and Summer 1992. In both experiments, there was a significantly lower percentage of weed coverage in the compost mulch and herbicide spray plots than in the control plots. Weed control in the compost and herbicide treatments was similar. In the spring experiment, tractor tire traffic through the alleys reduced weed growth in all plots by 62 % and 44% at 16 and 73 days after treatment initiation, respectively. These results suggest that municipal solid waste compost may have potential as a viable mulch for weed control in vegetable crop alleys. Chemical name used: isopropylamine salt of N -(phosphonomethyl) glycine (glyphosate).
M.S. Flanagan, R.E. Schmidt, and R.B. Reneau Jr.
The “heavy fraction” portion of a municipal solid waste separation process was evaluated in field experiments as a soil amendment for producing turfgrass sod. Soil organic matter and concentrations of extractable NO3-N, P, K, Ca, and Zn in the soil increased with addition of heavy fraction. Soil incorporation of heavy fraction resulted in greater air, water, and total porosity and lower bulk density of a loamy sandy soil. .Sod strength measurements taken 8.5 and 9.5 months after seeding were higher for Kentucky bluegrass (Poaprutensis L.) grown in heavy-fraction-amended topsoil than for turf grown in topsoil only. The use of this by-product may reduce the time required to produce a marketable sod. Soil incorporation of heavy fraction did not influence post-transplant rooting of Kentucky bluegrass sod but enhanced rooting of bermudagrass [Cynodon dactylon (L.) Pers.] sod at the highest rate evaluated. Results of these studies suggest that the use of heavy fraction for sod production may provide cultural benefits in addition to reducing the volume of solid waste deposited in landfills.
Christopher Worden, John C. Bouwkamp, Francis R. Gouin, and Charles McClurg
Vegetable culture with Municipal Solid Waste Compost (MSWC) amended soils was evaluated with the emphasis on crop and soil responses. There were three treatments of 0, 20, and 40 t·ha–1 of MSWC applied in the fall of 1993 to a Matapeake Silt Loam on the Eastern Shore of Maryland. The following spring the soil was prepared for planting tomatoes and green beans. All crop management practices were in accordance with the standard procedures followed in Maryland for each crop, except for the addition of the MSWC. Both crop yields were significantly increased with the addition of the MSWC. Following the bean crop, broccoli transplants were established in the fall of 1994. Again, the yields obtained with the MSWC plots as compared to the control were significantly greater. Soil properties were also favorably affected by the addition of the compost. Analysis of soil samples indicated significant increases with MSWC, such as cation exchange capacity, soil pH, percent organic matter, and water-holding capacity.
Catherine S.M. Ku, John C. Bouwkamp, and Frank R. Gouin
Municipal solid waste (MSW) may be a potential substitute for peat substrate in soilless medium. Adequate N and P are needed for a complete composting of MSW. MSW piles treated with diammonium phosphate (MSWP) or without P on Mar. 1994 were cured for 5 months. In Fall 1994, a factorial treatment combination of nine mixes and 3 fertigation treatments were evaluated in a completely randomized design on soft-pinched, single-stem `Red Sail' poinsettia. Mixes were MSW or MSWP ranging from 33% to 100% by volume in 1 peat: 1 perlite (v/v) and Sunshine mix was used as the control. Fertigation treatment began on the 1st, 2nd, or 3rd week after potting. Fertigation solution contained 266 mg·liter–1 N from 30N–4.4P–8.8K. The total fertigations ranged from eight to 10 for the 13-week study. With MSW mixes, shoot dry mass at the week 1 fertigation was 36% larger than at the week 3 fertigation. At the week 3 fertigation, shoot dry mass with 100% MSWP was ≈53% greater than with the 100% MSW. Shoot dry mass with 100% MSWP was similar to the control at the week 1 fertigation.
Nancy E. Roe, Peter J. Stoffella, and Donald Graetz
The composition of composts derived from municipal solid wastes can affect emergence and seedling growth. Composts consisting of biosolids and yard trimmings [standard compost (SC)] alone or with mixed waste paper (MWP), refuse-derived fuel (RDF), or refuse-derived fuel residuals (RDFR) were evaluated in seedling trays and pots for vegetable crop seedling emergence and growth. In trays, tomato (Lycopersicon esculentum Mill.), cucumber (Cucumis sativus L.), and pepper (Capsicum annuum L.) seedlings emerged faster from a commercial peat-lite mix and from sandy field soil than from the composts. Plants were tallest and shoots were generally heaviest in the peat-lite mix and aged SC and smallest in the field soil. MWP compost generally inhibited early seedling growth more than RDF or RDFR composts. Among the composts, seedlings were tallest and heaviest in SC. In pots, growth of each vegetable was generally greatest in SC, followed by other composts, and lowest in sandy soil. Tomato and pepper seedling emergence was more sensitive to the inhibitory effects of the RDF, RDFR, and MWP composts than cucumber seedling emergence. Fertilizer increased plant growth in each medium except SC, in which cucumber stem diameter was not increased. Adding MWP, RDF, or RDFR to SC generally decreased seedling emergence and growth. The composts prolonged days to emergence and decreased percent emerged seedlings. However, subsequent seedling growth in composts was equal to or greater than seedlings in the peat-lite mix and much greater than those in the sandy field soil.
Allen V. Barker
Major compostable materials in municipal solid wastes (MSW) are sewage sludge, paper, garbage, and autumn leaves. Five composts made from these wastes separately or in mixtures and one compost made from agricultural wastes (chicken manure and cranberry pomace) were evaluated for production of grass sods. Perennial ryegrass (Lolium perenne L. 'Pennfine') was seeded in 3.5-cm-deep layers of compost in plastic trays and grown in a greenhouse. Seed germination was inhibited in immature sludge-based and mixed MSW composts relative to germination in the other composts. High ammonium levels in the immature sludge-based and mixed MSW composts appeared to limit germination, as these composts had ammonium-N levels ranging from 1,000 to 2,000 mg/kg. Ammonium-N in the agricultural compost was 200 mg/kg, whereas that in the leaf-based composts was 10 mg/kg. In general, germination in all media was sufficient to establish a stand. Thereafter, growth of sods in the sewage-based, mixed MSW, and agricultural composts benefitted from the rich supply of N and exceeded that in the leaf-based composts. Mixing of composts with soil gave no advantage other than slightly increased seed germination but diluted total N supply and increased weediness of the sods.
N.E. Roe, S.R. Kostewicz, and H.H. Bryan
Several companies and government agencies are now making municipal solid waste (MSW) composts. This study was undertaken to test effects of a MSW compost with different rates of fertilizer on broccoli. Treatments were compost at 0, 6.7, 13.5 and 26.9 MT/ha and fertilizer at 84 and 168 kg/ha N on a, fine sand soil. Treatments were applied, rototilled, and beds formed and covered with black plastic. Broccoli cv. `Southern Comet' transplants were set on March 2 with 46 cm between plants, 2 rows/bed, and beds centered at 1.8 m. Mature heads 15 cm and larger were harvested on April 25. Numbers of heads and total weight of heads were recorded and average head weights were calculated. Data analysis indicated main effect significance for fertilizer rate but not for compost rate with no interactions. The 168 kg/ha level of N resulted in a yield of 5795 kg/ha while the 84 kg/ha level produced 3849 kg/ha. Average head weights were 264, 262, 257, and 252 g; and marketable yield were 5.0, 4.8, 5.0, and 4.5 MT/ha; at 0, 6.7, 13.5, and 26.9 MT/ha, respectively.
Maria Del Carmen Libran*, Dania Rivera, and Lizzette Gonzalez
In Puerto Rico, the ornamental crop production is one of the most important agricultural enterprises. The growing media most used to grow ornamentals contains peat moss which is very expensive and everyday results less available. There is a need to conduct studies to evaluate alternate organic components. In Puerto Rico, the Municipal solid waste compost (MSW) has been considered as a possible component for a growing mix to grow plants. Results from chemical properties studies of the MSW compost shows that it is a source of nutrients for plants. A raw MSW is a contaminat to the environment, but once is composted does not represent a hazard to humans or environment. The objective of this research was to evaluate the growth responses of Anthurium plants grown in mixes containing different proportions of MSW with a commercial type of mix containing peat moss. Plant of Rosa cultivar Anthura Co. were grown under six treatments containing proportions of MSW: Peatlite mix (0:100,15:85,25:75,50:50,75:25, and 100:0). Data of growth parameters such as number of leaves, leaf area index, clorophyll content, number of flowers, adn fresh and dry weight was gathered and analyzed. Results did show not significant differences in all treatments on number of leaves and leaves area. Clorophyll content was similar on treatment 0:100,15:85 and 25:75 of MSW: Peatlite mix. Fresh and dry weight (g) were lower in all treatments except on 0:100, which got the highest weight. These results shown that MSW could be considered to be a component of a soiless mix to grow ornamentals in order to reduce cost production and environmental impact.
Lizzette Gonzalez*, Juan C. Vazquez, and Maria del C. Libran
Municipal solid waste compost (MSW) can be used as an effective substrate for ornamental plant production as an alternative to peat. In a previous study a mix with peat, perlite, and vermiculite (1:1:1 per volume) was used along MSW compost at 1:1 per volume ratio as a growing substrate for Catharanthus roseus, providing nitrogen (N) for adequate plant growth. This study will focus in determining if MSW provides adequate amounts of N and Phosphorous (P) for Anthurium pot plant production, reducing the use of fertilizers and nutrient loss to the environment. Plants were fertilized at 0, 100, 150, and 200 ppm N using a 20-10-20 soluble fertilizer. Chemical characterization of leachates collected from plants grown in substrates with or without MSW, to determine possible nutrient run off. Tissue analysis for N and P content was conducted to determine absorption. Our results shows an increase in NH4 -N, NO3 -N and soluble P in leachates as the fertilizer level increased. Higher NO3 -N content in leachates was observed in treatments with MSW. Higher P concentrations were observed in leachates from substrate without MSW. Weeks after, 62% of the plants grown in MSW were dead; the surviving plants had less biomass, but similar N content in leaf and root tissues than plants grown without MSW. Higher P content in tissues was observed in fertilized plants grown without MSW. The MSW was a nutrient source for the plants, but further studies should be conducted for optimum use of MSW as a component of growing substrate.