Using Organic Waste Presents A Win-win Situation For Municipalities, Agriculture

Problem:
The concept of using organic wastes as fertilizer is not new. Before the industrial age in the 1940s when synthetic N fertilizer became widely available, animal manure and human waste were the primary amendments to agricultural soils for improving crop yields around the world. Crop fertilization with organic waste has received renewed interest as municipalities face increasing disposal problems. Florida's human population growth from 4 million in 1955 to 16 million in 2000 is among the highest in the nation. Prohibition of waste dumping in streams and oceans, diminishing landfill space, skyrocketing landfill costs, and concerns over air pollution from incineration of waste have contributed to a strong public interest in finding alternative, environmentally sound solutions to waste disposal. Many livestock producers apply biosolids to their pasture to reduce cost of fertilizer and lime, but landowners are justifiably concerned about potential negative effects of applying such waste to the land. In decreasing order of importance, the potential for pathogen spread, heavy metal accumulation on agricultural land, excessive loading or volatilization of plant nutrients with nonpoint source pollution potential, and odor to the neighborhood are contentious issues regarding the use of biosolids for crop production.

Challenge:
The cow–calf industry in Florida depends almost totally on grazed pastures. Seventy-five percent of the 1 million ha of improved pastures in Florida contain bahiagrasses. Nitrogen is the most limiting nutrient for pasture production so annual inputs of N from organic and inorganic sources are needed to produce adequate forage. Biosolids are applied to large areas in Florida. In 1995, 66% of the slurry and cake biosolids from Florida's population were land applied, 17% were land filled, and 8% were incinerated (Kidder, 2001). Land application of biosolids returns essential plant nutrients to the soil, releases them slowly to the crop, improves the organic matter content of the soil, and acts as liming material if it has been previously lime-stabilized. There is little information available that confirms or disputes the beneficial use of biosolids for forage production. The objective of this study was to compare the effects of organic sources of N with inorganic sources on bahiagrass establishment, forage production, and nutritive value.

Conclusion:
Funded in part by the Florida Department of Agriculture and Consumer Services, the study showed liquid forms of sludge are just as effective as traditional synthetic fertilizer. Some minerals such as phosphorus, calcium, and iron were higher in crops fertilized with sludge. In a very dry year, the water in liquid sludge can also enable nutrients to reach the crop’s rooting zone more effectively than synthetic fertilizer. Liquid sludge if processed and applied according to specific guidelines has the potential to boost production dramatically. It is low in pathogens, inexpensive, and environmentally safe.

Please see pdf document for full report - 78K.

E-mail This Article		Related Links
Send this article to: Your e-mail address: Message (optional):