One of the most common types of prepackaged alternative soil amendments is the manure- or compost-based blended fertilizer. Several of these products have national distribution, and many more enjoy a loyal regional following.
Such products are typically analyzed at 2% — 5% for each nutrient. Dried compost is used as a bulking agent, source of nutrients, and organic matter. It is blended with several of the materials discussed in this publication, including rock minerals and plant and animal by-products. Nearly all products of this class sell for prices about three times greater than their conventional fertilizer value, but may be quite effective in farm situations. However, homeowners with access to other sources of manure or compost can realize substantial savings by relying on local manure resources for their lawns and planting beds..
Composted sewage sludge is marketed as a fertilizer and soil amendment. This compost provides organic matter and a number of nutrients, and as marketed, is solid with little odor.
The greatest potential problems with using composted sludge are heavy metals from industrial waste, along with assorted chemical contaminants (from household cleaners, latex paint, and other things people flush down their drains).
Pathogens are controlled fairly easily through proper composting, which raises the temperature of the composting material sufficiently to kill many microorganisms. The U.S. Environmental Protection Agency has established strict guidelines for pathogen control, which most sewage composting facilities follow.
Heavy metal contamination is a significant risk wherever industrial facilities contribute to sewage. Contamination by heavy metals and many other chemicals is limited as much as possible with current technology, but composted sludge often contains levels that make it unsuitable for use on food crops.
Before using any composted sludge or other treated municipal waste product in crop production, the grower must know the chemical composition of the product and whether it is safe to apply to food crops. Have the sludge tested. It is important to note that at least 38 states regulate the production of sewage compost. Its use is prohibited in all certified organic farm production.
