Part 1, Section 9: Nontraditional Soil Amendments
Nontraditional Soil Amendments
WATER TREATMENT RESIDUALS
These are sediments removed from water supplies during the preparation of potable water. Water is treated with a coagulant, most commonly alum, to cause clay and silt in the water to settle out quickly. The residual is a mixture of clay and silt minerals, some organic matter, and the coagulant. Although water treatment residuals have the appearance of a fine-textured soil, they do not appear to benefit agronomic crop production. Many water treatment residuals have the capacity to fix phosphorus, and research is being conducted to determine if soil application will reduce phosphorus in runoff from high P-test soils. Water treatment residuals are generally quite low in trace elements of environmental concern.
This brief overview of nontraditional soil amendments does not include all the possible by-product materials that may be available to farmers, nor does it fully describe all the possible benefits and problems that could be associated with any particular material. While many of these materials can provide benefits to soil quality and crop production, farmers must investigate each individual material carefully to be certain it will provide the expected result. Such investigation needs to look at both the positive and negative effects of the material on soil quality for sustained crop production. For most materials, this will require several chemical analyses of the appropriate major and trace elements and other properties. Determination of appropriate application rates and assessment of possible negative effects can only be done on the basis of such analysis.