Agricultural users are among the most hesitant to use MSW compost, which they fear contains unsafe levels of heavy metals and other contaminants that can damage crops. Heavy metals, herbicides, pesticides, and other potential toxics, however, are generally not a concern with composted yard trimmings. This lack of standards also may steer some potential users away from compost. Another factor that affects demand is the availability of compost compared to its competing and complementary products on the market, including fill dirt, top-soils, riverbottom silt, potting soils, custom soil mixes, bark mulch and wood chips, manure, peat moss, mushroom compost, perlite, and vermiculite. Many of these products have a long history of consistency, availability, reliability, acceptance, and use in agriculture, horticulture, public and private landscaping projects, and residential gardening.
Distance also is a factor affecting demand.
Proximity to composting facilities promotes product acceptance and recognition. Thus, a potential user is more likely to know of a product that is produced nearby, rather than one produced many miles away. Shipping costs, however, might exceed the value of compost, which may already be low. The agriculture industry is the largest potential market for compost, although it is also the most difficult to penetrate. To increase the use of compost by this industry, the compost must be available at the appropriate time of the year, consistent in composition and nutrient content, contain low levels of potentially toxic substances, be offered at a low cost, and be accepted by farmers.