Wastewater sludge contains high levels of organic matter and significant amounts of essential nutrients and trace elements for plant growth. Moreover, sludge can be considered a slow-release fertilizer as a result of its high concentration of
Ugur Bilgili, F. Olcay Topac-Sagban, Irfan Surer, Nejla Caliskan, Pervin Uzun, and Esvet Acikgoz
J. Norrie and A. Gosselin
The behavior of turfgrass grown on paper-sludge-amended soils was evaluated over 2 years. Two experiments were performed, one with deinked sludge and another with primary sludge. Four paper sludge, sand, and organic soil substrate mixtures with proportions ranging from 0% to 50% paper sludge were incorporated into existing soils. Two fertilization levels were applied in strip plots across sludge treatments and three turfgrasses of seeded Kentucky bluegrass (Poa pratensis L. `Georgetown'), Kentucky bluegrass sod, and an 80 Kentucky bluegrass: 20 perennial ryegrass (Lolium perenne L. `Prelude') seed mix were arranged within split plots. Effects of deinked and primary sludge experiments were similar. Supplemental N and, to a lesser degree, P and K fertilization with N at ≈4.5 to 5.5 t·ha–1, P at 1.18 to 1.26 t·ha–1, and K at 1.34 to 1.46 t·ha–1 improved ground cover, turf color, and stand quality. Despite differences in visual evaluations, leaf mineral nutrition was only slightly affected by fertilization treatments. Soil in nonfertilized plots was several times lower in N-NO3 when compared to fertilized plots, regardless of sludge rate. Soil in fertilized plots had higher concentrations of inorganic N regardless of sludge amendment. The soil C: N ratio was ≈13:1 in nonamended plots and more than 15:1 under the highest sludge rate. Deinked and primary paper sludges can be used effectively as soil amendments if turfgrass receives adequate supplemental N, P, and K.
Calvin Chong and R.A. Cline
sludges were supplied by the Quebec and Ontario Paper Co., Thorold, Ont., and the Noranda Forest Recycled Papers, Thorold. Technical assistance was provided by Bob Hamersma and Debbie Norton. The cost of publishing this paper was defrayed in part by the
S. A. Mackintosh and R. J. Cooper
Environmental concerns associated with traditional methods of sludge disposal have spurred research exploring alternate avenues of disposal. A potentially significant alternative is the beneficial use of sludge as a turfgrass fertilizer. Studies were initiated during 1991 to compare a commercially available pelletized sludge to urea; 12-4-6; Ringer Lawn Restore; and Milorganite. Fertilizers were evaluated for their effect on turfgrass quality, color, and growth rate. Treatments were applied to a stand composed of 65% Kentucky bluegrass (Poa pratensis L. `Baron') and 35% Perennial ryegrass (Lolium perenne L. `Manhattan II') in South Deerfield, MA. Urea and 12-4-6 were applied at 49 kg N ha-1. Ringer Lawn Restore and Milorganite were applied at 98 kg N ha-1. Pelletized sludge was applied at 98, 196, 294, and 392 kg N ha-1 with all rates providing acceptable to good turfgrass color throughout the season. Rates of 294 or 392 kg seldom provided quality better than the 196 kg rate. While urea initially produced quality superior to pelletized sludge, all rates of sludge resulted in quality equal to or better than urea beginning one month after application and lasting approximately 11 weeks. Turf receiving similar rates of either pelletized sludge or Milorganite performed similarly. No sludge application rate produced burning or foliar discoloration. Clipping production was directly related to sludge application rate. Pelletized sludge applied at 98 kg N ha-1 resulted in growth comparable to similar applications of Ringer Lawn Restore and Milorganite. In summary, using pelletized sewage sludge as a turfgrass fertilizer promotes healthy turfgrass while creating an alternate avenue of sludge disposal.
M. B. Kirkham
Chrysanthemum plants (Chrysanthemum morifolium Ramat. cv. Bright Golden Anne) were grown for 84 days in plastic pots containing media treated with inorganic fertilizers or liquid sewage sludge, added at a rate of 50, 100, or 200 ml/week, to determine if sludge could be used as a fertilizer. Plants grown with sludge at all application rates had higher N and lower K concentrations compared to plants grown with inorganic fertilizers. Leaf concentration of P, Ca, Mg, Fe, Zn, Cu, Cd, Ni, and Pb of plants grown with 50 ml sludge/week were similar to plants receiving inorganic fertilizers. As sludge application rate increased, leaf concentrations of Fe and Cu increased of plants grown in media consisting of all sand or all peat and Zn increased in leaves of plants grown in the standard greenhouse media (1 soil: 1 sand:l peat, by volume). Sludge-treated media had a higher pH and extractable Cu concentration, and a lower extractable K concentration, than media without sludge. Plants receiving 50 ml sludge/week grew as well as plants grown with inorganic fertilizers.
Francis R. Gouin
Sewage sludge is being converted to compost by many municipalities. Its use in the production, establishment, and/or maintenance of horticultural crops is dependent on soluble salt concentration, particle size, stability, dewatering procedures, storage conditions, and crop needs. Soluble salt concentration has the greatest effect on the amount of compost that can be used as a soil or potting media amendment. Because composted sewage sludge is rich in plant nutrients, it can supply many of the nutrient needs of plants, depending on the amount used and if the plants are growing in the ground or in containers. However, improper storage of composted sewage sludge can render the product useless due to the accumulation of acetic acid and alcohol that occur under anaerobic conditions.
Robert F. Bevacqua and Valerie J. Mellano
Compost made from sewage sludge (40% by volume) and chipped trimmings of Eucalyptus trees (60%) was evaluated as a soil amendment for the field. production of onion (Allium cepa cv. Spanish Sweet Utah), lettuce (Lactuca sativa cv. Black Seeded Simpson), snapdragon (Antirrhinum majus cv. Sonnet Yellow), and turfgrass (Festuca arundinacea cv. Marathon). Turf shows a strong reponse to preplant compost applications and is relatively tolerant of the buildup of soluble salts that can occur with compost applications. Also since it is not a food crop the possible uptake of heavy metals is not a major concern. These results indicate the amending of soil for the planting of turf is a likely commercial use of the compost. The authors are presently evaluating the use of the compost as a top dressing on turf plantings.
Robert R. Tripepi
Paper sludge is a fibrous material that may be suitable as a replacement for peat moss in potting media. The goal of this study was to compare the growth of potted `Iridon' mums (Dendranthema × grandiflora Tzvelev.) grown in sludge-amended media against that of plants in two peat-based commercial mixes. Paper sludge from a newsprint mill was composted 6 weeks. Plants were grown in a European pot mum regime with three rooted cuttings planted in square 10-cm pots containing either a commercial mix or a sludge-amended medium [75% sludge: 15% perlite: 10% vermiculite; or 50% sludge: 33% peatmoss: 17% perlite (by volume)]. Plants were grown for 12 weeks and not disbudded before plant growth indices were determined. Mums grown in sludge-amended media appeared similar to those grown in the commercial mixes. Plants grown in either sludge-amended medium were slightly shorter (1.5 cm) and narrower (2.5 cm) than those grown in the commercial mixes. In addition, mums grown in sludge-amended media produced eight fewer flowers and 4 g less shoot dry weight (per pot) compared to plants in commercial mixes. Composted paper sludge appears to be suitable for production of `Iridon' pot mums, even though plants grown in this material grew slightly less than those in commercial media.
M. B. Kirkham and E. R. Emino
Chrysanthemum plants (Chrysanthemum morifolium Ramat. cv. Bright Golden Anne) were grown for 84 days in plastic pots containing 6 different media treated with inorganic fertilizers or liquid digested sewage sludge at 50, 100, and 200 ml/week. Plants grown in 1 soil: 1 sand: 1 peat, 1 soil: 1 sand, and 1 soil: 1 peat were similar to each other in size, and larger than plants grown in 1 sand:1 peat, all sand, or all peat. Peat-grown plants were smallest. Plant size and flower diameter decreased with increasing rates of sludge application. Plants fertilized with inorganic sources of fertilizer looked the same as those grown with 50 ml/week sludge (6 mm), except the sludge-treated plants were shorter and had a smaller dry weight. Plants treated with 50 ml/week sludge had flowers with a diameter and dry weight equal to those of flowers grown with liquid or pelletized inorganic fertilizer.
Helen C. Harrison
A 2-year carrot (Daucus carota L.) nutrition experiment involving 3 sludge treatments, 3 bed types, and 3 advanced hybrid carrot selections was conducted on a silt loam in Arlington, Wis., to determine the influence of these variables on growth and elemental concentration levels in edible, mature carrot roots. Sludge treatments included a 90 MT/ha/year application of municipal or industrial sludge plus a control with no sludge application. When significant differences occurred, highest yields and elemental concentration levels in edible roots occurred with hybrids grown in municipal sludge-amended soils. Root Cd levels in 1982 were the only exception, being greatest in plants grown on industrial sludge-amended soils. Lowest yields and highest heavy metal concentrations in the edible root were found in carrots grown on overcover beds (15-cm raised bed of unamended topsoil over prepared level or flat bed) as compared to those grown on 15-cm raised beds or level beds. Hybrid carrot selection (B6373 × B6345) × B6274 (B) accumulated less heavy metals in its edible root tissue than did B4367 × B6274 (A) or (B34602 × B3316) × F524 (C).