During the last 10 yr, research was established in the Niagara region of Ontario to assess the use of paper sludge on agricultural land. Compositionaily, the sludges are relatively free of chemical contaminants. These sludges are used primarily as an organic amendment rather than as fertilizers, because of low mineral nutrient contents. Greenhouse, nursery container media, and field experiments showed increased growth and yield of various horticultural and agricultural crops, thus demonstrating the beneficial effects of paper sludges as organic amendments to potting media and field soils. Small to moderate deficiencies in N in certain sludges are readily compensated by adding fertilizer to soil or sludge. From field plot studies, increases in growth and yield for selected crops have been realized with a recommended sludge application rate of 12 dry Mg ha -~ provided sufficient N fertilizer is applied.

. 1998. Comparative rooting of deciduous landscape shrub cuttings in media amended with paper mill biosolids from four different sources. Can. J. Plant Sci. 78: 519-526. Scarcity of landfills has resulted in increasing need for alternative disposal or reuse of industrial organic wastes such as paper mill sludge (biosolids). The objective of this study was to evaluate and compare the rooting response of stem cuttings from six species of deciduous landscape shrubs [coralberry (Symphoricarpos × chenaultii Rehd. 'Hancock'); flowering almond (Prunus triloba Lindl. 'Multiplex'); honeysuckle (Lonicera × xylosteoides Tausch. 'Clavey's Dwarf'); mock orange (Philadelphus × virginalis Rehd. 'Minnesota Snowflake'); purple-leaf sandcherry (Prunus × cistena N. E. Hansen); and viburnum (Viburnum dentatum L.)] under mist and 50% shade (outdoor lath) in flats filled with 100% perlite medium, or perlite mixed with 15, 30, 45 or 60% of fresh paper mill biosolids, by volume, of one of four sources (Atlantic, Domtar, Thorold, and QUNO). There was little or no adverse effect of the biosolids, despite wide variability in rooting response due to species, source and/or level of biosolids. Regression analyses indicated that, with few exceptions, the percent rooting, mean root number per rooted cutting, and length of longest root per cutting increased linearly or curvilinearly, or was unaffected, when regressed over level of biosolids. Optimum amounts of biosolids in the rooting medium ranged from 30 to 60% by volume. The electrical conductivities of the biosolids-amended media were acceptable (0.1-0.3 dS m -1 ) for rooting of woody cuttings and pore space characteristics were comparable to, or exceeded those of, perlite. symphorine (Symphoricarpos × chenaultii), amandier ornemental (Prunus triloba Lindl. cv. Multiplex), chèvrefeuille (Lonicera × xylosteoides Tausch. 'Clavey's Dwarf'), syringat (Philadelphus × virginalis Tausch. 'Minnesota Snowflake'), cerisier à feuilles pourpres (Prunus × cistena N. E. Hansen) et viorne (Viburnum dentatum L.). Les boutures étaient mises en plateau sous nébuli-sation, en ombrière extérieure (50 % d'ombrage). Les substrats étaient faits de perlite à 100 % ou mélangée avec 15, 30, 45 ou 60 %, en volume de boues d'épuration fraîches de papeterie de l'une ou l'autre des provenances suivantes : Atlantic, Domtar, Thorold et QUNO. Les boues ne causaient pratiquement pas d'effets négatifs, malgré la large variabilité du racinage liée à l'espèce végétale et à la provenance ou à la dose d'incorporation des boues. À partir de l'analyse de régression, nous avons constaté qu'à quelques exceptions près, le pourcentage d'enracinement, le nombre moyen de racines par bouture racinée et la longueur de la plus longue racine par bouture augmentaient en fonction linéaire, curvilinéaire ou pas du tout, selon la dose d'incorporation des boues. Les doses optimales se situaient entre 30 et 60 % en volume. Les valeurs de conductivité électrique des substrats contenant des boues étaient acceptables (0,1 à 0,3 dS m -1 ) pour l'enra...

Pulp and paper, a $20 billion industry in Canada, generates large quantities of effluent waste. For disposal purposes, the waste is typically dewatered into raw sludge or biosolids (30-45% total solids). About 1 million tonnes of this waste product is generated annually.Like other industrial wastes, the disposal of paper mill biosolids is a major concern. Landfilling has been restricted or has become prohibitively expensive. Environmentally friendly and sustainable disposal alternatives are being sought.Since the 1950s, research has assessed the use and benefits of using paper mill biosolids in land reclamation, forestry, and in agriculture. More recently, biosolids have been used successfully to amend soils for field-grown horticultural crops, or used raw or composted in substrates for container nursery crops.In an investigation conducted at the Horticultural Research Institute of Ontario, paper mill biosolids from one source (QUNO) were used effectively as a medium amendment for rooting nursery cuttings under mist. Since biosolids are derived from widely different manufacturing sources, often with different end-uses, can other sources of biosolids be used similarly in nursery rooting media?Current season terminal cuttings were taken in early summer from six deciduous woody shrubs: coralberry, flowering almond, honeysuckle, mock orange, purple-leaf sandcherry, and viburnum. The cuttings were treated with a rooting hormone (5000 ppm indolebutyric acid) and inserted in flats filled with 100% perlite medium, or perlite mixed with 15, 30, 45 or 60% by volume of raw paper mill biosolids from one of four sources (Atlantic, Domtar, Thorold, and QUNO). Rooting occurred under mist and 50% lath shade. The response of species in each treatment was assessed 3 to 4 weeks later in terms of the percent of cuttings rooted, number of roots per rooted cutting, and length of the longest root per cutting.Despite wide variability in rooting response among species, source, and/or amount of biosolids in the rooting media, statistical (regression) analysis showed remarkable consistency in the results. There was little or no discernable adverse affect of the biosolids on the cuttings. With few exceptions, optimum rooting occurred when between 30 and 60% (the highest level tested) of biosolids were present in the rooting media. There was no clear indication that any one of the sources was consistently or substantially better than the other in promoting rooting.In this study, physical analysis indicated that the pore space characteristics of the biosolids-amended media were comparable to, or exceeded, those of perlite. Also, chemical analysis showed that the initial concentrations of all nutrients in the unamended biosolids were relatively low or within acceptable ranges, and values in electrical conductivity (EC, a measure of the soluble salts content) ranged from 0.2-0.7 dS m -1 . After preparation of the mixes and initial watering of the flats, and throughout the rooting period, the EC values in the amended mixes were within an accept...