Paper Sludge Utilization in Agriculture and Container Nursery Culture

During the last 10 yr, research was established in the Niagara region of Ontario to assess the use of paper sludge on agricultural land. Compositionally, tbe 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 -1 provided sufficient N fertilizer is applied.