Submitted to: Sustainable Agriculture
Publication Type: Book / Chapter
Publication Acceptance Date: August 12, 2010
Publication Date: September 28, 2010
Citation: Sigua, G.C. 2010. Recycling biosolids and lake-dredged materials to pasture-based animal agriculture: Alternative nutrient sources for forage productivity and sustainability. In: Lichtfouse, E., Navarrete, M., Debaeke, P., Souchere, V. and Alberola, C., editors. Sustainable Agriculture. Volume 1. New York:Springer. p. 495-505.
The prohibition of dumping dredged and domestic sewage sludge (DSS) materials in streams and oceans, diminishing land fill space, skyrocketing landfill costs, and concerns over air pollution from incineration of wastes have contributed to a strong public interest in finding alternative, environmentally sound solutions for disposal methods. The most important step in evaluating the sludge and dredged materials application alternatives is to determine whether these materials are suitable for agricultural land. Domestic sewage sludge or biosolids, composted urban plant debris, waste lime, phosphogypsum, and dredged materials are examples of materials that can be used for fertilizing and liming pastures. Perennial grass can be a good choice for repeated applications of DSS and lake-dredged materials (LDM). Although DSS supply some essential plant nutrients and provide soil property-enhancing organic matter, land-application programs still generate some concerns because of possible health and environmental risks involved. Repeated applications of DSS indicate no harmful effects on soil quality and forage quality. Land application of DSS to supply 90 and 180 kg N ha-1 would not increase soil sorption for nutrients and trace metals. The concentrations of soil nitrogen and phosphorus following repeated application of DSS were far below the contamination risk in the environment. The residual effect of this DSS over the long term can be especially significant in many forage-based pastures where only 50% of the 1 million ha of pastures are given inorganic nitrogen yearly. Beneficial uses of dredged materials are both economical and environmental. Results have demonstrated the favorable and beneficial effects of added LDM on the early establishment of bahiagrass in pasture fields. Often these materials can be obtained at little or no cost to the farmers or landowners. Dredged materials can be used as soil amendments (lime and fertilizer) for early establishment of BG in beef cattle pastures. Our results have shown the favorable influence that LDM had on the yield of BG during its early establishment in subtropical beef cattle pastures. Bahiagrass in plots that were treated with LDM had significantly higher forage yield and crude protein when compared with those BG in the control plots.