Part 1, Section 9: Nontraditional Soil Amendments
Nontraditional Soil Amendments
The industrial, commercial, and municipal sectors of Pennsylvania and surrounding states produce both large quantities and a wide variety of waste materials. Traditionally, most of these wastes were discarded by landfilling or incineration. During the past 20 years, however, generators of these wastes or byproducts have increasingly sought to find beneficial uses for them. This is being done both for environmental reasons (to recycle resources in the wastes and decrease the need for landfills and incinerators) and for economic reasons (to avoid the cost of disposal and possibly gain some income from the waste). A beneficial use that has been identified for several byproduct materials is application to agricultural land as soil amendments. Some byproduct materials are intentionally being processed further to increase their value and to make them more suitable as soil amendments. Examples of this include the composting of organic wastes such as leaves and grass, food processing wastes, sawdust, and sewage sludge.
All soil amendments, including traditional amendments such as chemical fertilizers and pesticides, have both beneficial and detrimental effects on soil and environmental quality. The positive and negative effects of most traditional soil amendments are clearly understood, and years of experience and research have helped us learn how to manage these materials to maximize their beneficial effects and minimize or eliminate any detrimental effects. While some by-product materials such as sewage sludge or biosolids have been extensively researched and are widely used, this is not the case for most of them. Some by-products may be used as a source of plant macro- and micronutrients; others may be used as a limestone substitute to neutralize soil acidity. Some may add organic matter to soils; and others may be used as a soil conditioner. Furthermore, these beneficial effects generally will be provided at no or very low economic cost to the farmer. In some cases, the farmer may be paid to accept the material. These same materials, however, might contain trace metal and organic chemical contaminants that could negatively affect plants, animals, or humans. Some may contain disease-causing organisms, give off offensive odors, or generate a lot of dust when spread. Variability in by-product consistency and quality could lead to difficulties in transport, storage, handling, and determining appropriate application rates. Thus, a decision about whether or not to use a particular by-product requires careful investigation of both its possible benefits and its possible drawbacks. Before using a by-product material, farmers should be certain that it will provide the benefits they are expecting. They also should have an equally clear understanding of its possible negative effects and problems.
Because of the great variety of by-product materials available, specific information about each one cannot be provided here. Following are general descriptions of various categories of byproducts. For each type of material, the possible benefits and some possible negative effects and problems are given. It must be emphasized, however, that because byproducts vary a great deal depending on how, when, and where they are produced, farmers must carefully investigate the characteristics of the particular material they are considering using. Although state and federal regulations provide some guidance and protection, ultimately it is up to the farmer to determine if a by-product will truly benefit his or her production system.