During the past 20 years, the Ornamental Nursery Research Program at the former Horticultural Research Institute of Ontario (now part of the University of Guelph) has been conducting applied research dealing with environmentally friendly and sustainable nursery production practices with emphasis on container production. The use of farm, industrial, and consumer waste by-products as amendments in nursery substrates has been a major focus. The program has evaluated hundreds of potting mixes derived from individual or combined, raw or composted waste by-products including spent mushroom compost, turkey litter compost, paper mill sludge, municipal waste compost, corrugated cardboard, apple pomace, wood chips from pallets, pulverized glass, and various types of tree barks. With few exceptions, all the above waste by-products tested under our cultural conditions provided acceptable to excellent container-growing media, often in amounts exceeding 50% and sometimes up to 100% by volume in No. 2 containers (6 L), even despite initially elevated and potentially toxic contents of soluble salts [expressed in terms of electrical conductivity measured up to 8.9 dS·m-1 in 1 substrate: 2 water (by volume) extracts] in many of the substrates. A key to these successful results is that salts leach quickly from the containers to benign levels (∼1.0 dS·m-1) with normal irrigation practices. High initial pH in most waste-derived substrates (up to 8.9) has had little or no discernible effect on growth of a wide assortment of deciduous nursery species. By-products such as paper mill sludge and municipal waste compost with soluble salts contents typically ranging from 0.8 to 2.0 dS·m-1, also provide acceptable rooting media provided salts are leached before use to values ≤0.2 dS·m-1. The porosity and aeration characteristics of waste-derived substrates tend to be comparable to, or better than, those of bark.
P. Lecomte, M. Laganière and Y. Desjardins
Increasing costs associated with the disposal of industrial and urban wastes necessitate the development of alternatives which are economical and environmentally safe. With >3000 ha in Quebec, sod production represents an interesting alternative for the use of new amendments, such as composted de-inked paper sludges and municipal waste compost. The objective of this trial was to evaluate the potential benefits of these amendments (nutrient retention in the root zone and chemical and physical soil benefits) and question potential environmental hazards. Chemical dynamics of N, P, K, micronutrients and heavy metals were examined over four soil layers (0 to 15, 15 to 30, 30 to 60, an >60 cm) on sandy and clay soil. Preliminary results for 1993 and 1994 indicate that nutrient concentrations in water extract are high following the establishment of sites. When sod is absent, high concentrations of lead (500 mg·kg–1 in urban compost) show only a slight trend to accumulate. Nevertheless, this new approach toward using industrial and urban composts seems to be adequate and economically attractive.
Handell Larco, Bernadine C. Strik, David R. Bryla and Dan M. Sullivan
than N are present in organic fertilizers and are thus applied to the planting whether required or not. The impact of using organic fertilizers on plant and soil nutrient levels is largely unknown in most crops, including blueberry. Compost is also used
The general population is constantly reminded of the need to adopt a more environmental-friendly approach to waste disposal on all scales. Commercial fishing generates large proportions of waste, ranging from 40% to more than 80% of the catch! The objective of conserving the nutrients and other organic values contained in this type of waste is unlikely to be fully met by bulking for aerobic composting with materials of low buffering capacity, such as straw or wood wastes. However, the capacity of peat for deodorizing of decomposing organic wastes as well as its high buffering capacity has been well demonstrated. This presentation shows how the incorporation of sphagnum peatmoss in a composting process contributes significantly to the production of a valuable organic soil amendment.
Matt Welch and D.L. Creech
The poultry industry is a $1 billion industry in Texas, with most production centered in eastern Texas. The nursery industry is a $600 million industry, with 25% of the producers located in eastern Texas. With hundreds of millions of birds produced each year, and each bird producing ≈2 lb of manure, waste disposal is a growing problem. Composted poultry litter was mixed with composted pine bark to create five media with varying percentages of poultry litter as a component: 0%, 5%, 10%, 20%, and 40%. A randomized complete-block design was used with poultry litter rates as main plots and plant species tested as subplots. Five species included: tomato, marigold, Cortaderia selloana, Asian jasmine, and Salvia leucantha. Prior to planting, all 1-gal containers were leached with 1000 ml of water, the leachate collected, and tested for conductivity. Plant growth measurements to be presented include plant height and dry weight. The results of media and leaf tissue nutrient analysis will be presented.
Dennis B. McConnell and Wayne H. Smith
Three foliage plants, Dracaena fragrans, Peperomia obtusifolia and Schefflera arboricola were grown in 24 different mixes. Potting mixes were formulated using yard waste compost from two sources, a commercial mix (Metro 300) and a prepared mix (peat: pine bark sand). All potting mixes produced acceptable plants with no phytotoxicity associated with any mix. Only minor differences were discerned in the growth rate of P. obtusifolia and S. arboricola.
The growth rate of D. fragrans showed the greatest response to potting mix formulations. Plants in a standard potting mix (P/PB/S) used in the industry for D. fragrans grew slower than plants in many of the mixes containing various fractions of yard waste compost. Chemical and physical properties of the potting mixes used showed physical properties had the greatest variability. Overall, the best growth for all 3 plants was in a potting mix composed of 87.5% Metro 300/12. 5% YWC#1 and worst growth was in YWC#2 (100% composted (live oak leaves).
Barakat Abu-Irmaileh and Azmi Abu-Rayyan
Fresh manure is normally broadcasted on the soil surface in vegetable growing areas of Jordan as a source of nutrients and organic matter. However, it can be an environmental pollutant and may lead to the outbreak of many health-related pests, especially houseflies. Field experiments were conducted in two locations to study the effect of in-row composting of four different fresh manures and olive pomace on preplant weed control in vegetables. In the first experiment, main treatments were as follows. 1) Organic materials were applied preplant and then the soil was covered with black polyethylene (BPE) sheets for 6 weeks (M). 2) Treatments were the same as in (M) but the soil surface was covered by BPE mulch for the whole growing season (MP). 3) There was soil incorporation of organic materials preplant, but the soil surface was unmulched during the 6-week period and weeds were controlled chemically later in the season (MC). 4) For the control (C), fresh organic materials were soil incorporated manually at time of planting. Each main treatment included four subtreatments. Each subtreatment received a different source of organic material: cow, poultry, or sheep manure or olive pomace. In the second experiment, the rates of poultry manure (0, 5, and 10 kg·m-2) comprised the main treatments. Each treatment included four subtreatments in which the manure was soil-incorporated then subplots were covered by BPE sheets for either 0, 2, 4, or 6 weeks. The composting process in the main treatments M and MP raised soil temperatures significantly at a 15-cm depth above soils without manure amendments. Soil temperatures were higher, especially with poultry manure, athough not significantly different in all cases. Composting poultry manure was more effective in reducing weed dry weights compared with other organic materials.
T.K. Hartz, F.J. Costa and W.L. Schrader
The study was undertaken to determine the physiochemical properties and nutrient supply characteristics of composted green yard and landscape waste (CGW) and to document its performance as a field soil amendment or constituent of potting media. Three CGW samples were collected from each of two composting operations in California from Nov. 1993 to Apr. 1994. Macronutrient content varied widely between operations, and among samples from the same operation, with mean total N, P, and K levels averaging 1.1%, 0.26%, and 0.67%, respectively. Controlled-environment incubation of a moist 1 CGW: 9 soil blend (2 weeks at 30 °C) was conducted to determine net N mineralization from CGW. Despite low C: N ratios (<12), five of six CGW samples showed net immobilization, a characteristic of immature compost. An in-field incubation of soil amended with 1% or 2% CGW (w/w) showed no net N release from CGW over 4 months. In a field trial, bell pepper (Capsicum annuum L.) fruit yield was increased by soil amendment with CGW (17 or 34 t·ha–1) under a low N fertilizer regime (168 kg·ha–1), but was unaffected where sufficient fertilizer N (280 kg·ha–1) was applied. CGW was compared with peat as a constituent of potting media; both were blended 1:1 (v/v) with perlite and used in the production of tomato (Lycopersicon esculentum Mill.) and marigold (Tagetes erecta L.) plants under varying fertigation regimes (constant feed of N at 0, 50, or 100 mg·L–1 as 15N–13P–12K). CGW was equivalent or superior to peat in plant growth; CGW did contribute to crop macronutrient nutrition, but the highest fertigation rate was required for optimum growth.
Alicia Sanchez-Escarcega and George C. Elliott
Growth inhibition has been observed with plants grown in potting media containing compost. The objective of this study was to determine if
Heidi J. Johnson, Jed B. Colquhoun, Alvin J. Bussan and Carrie A.M. Laboski
meet crop N needs such as using N-fixing legumes as GrM crops, composted manure, and commercially available amendments ( Gaskell and Smith, 2007 ). Composted manure is a cost-effective means of providing N to an organic crop because of its role as a