This is a unique experiment because several different composts, made from materials commonly available to farmers (both rural and urban sources), are being compared to conventional fertilizers and raw dairy manure. Composting is rapidly becoming an attractive approach to waste management for several reasons. Despite the use of best management practices, including overall reductions in fertilizer applications, unsafe amounts of nitrate gets into groundwater from farmland, resulting in concentrations that consistently exceed the EPA's maximum levels for drinking water. As a result, farmers are required to adopt practices that reduce water contamination. At the same time, the number of municipalities prohibiting the disposal of yard waste in landfills has increased in the last decade. One obvious solution to both the urban landfill restrictions and the on-farm nitrogen management problems is co-composting of farm animal wastes (usually high in nitrogen) with municipal yard and garden residues (usually high in carbon but low in nitrogen). Since the high carbon material serves as an energy source for microbes, soluble nitrogen in the animal wastes is converted to a more stable form.
The experiment will be in its third field season in 1995, and we will intensify soil sampling to include several biological and physical parameters, since we are now at a point where we should be able to detect differences in soil quality. We expect that the use of compost in place of conventional mineral nitrogen fertilizers or raw farmyard manures will lead to reduced nitrate leaching. Besides stimulation of the microbial community and nutrient stabilization, the benefits of compost extend to overall improvement of soil physical characteristics, which will significantly contribute in the long-run to reducing soil erosion. Our research in the CUT experiment will allow us to ensure that the agricultural use of these materials is environmentally sound and to determine the long-term effects of various composts on soil and crop quality.
- Assess the value of composting in recycling farmyard manures and urban organic residues
- Identify agricultural uses for finished composts and assure their use is environmentally sound
- Determine advantages and disadvantages over time of using compost as a fertilizer from a farmer's point of view
- Examine the effects of compost use on soil health and crop quality over time
- Compare economic and energy costs of compost compared to raw manure and conventional fertilizer
- Address questions about soil health and its relationship to food quality (nutritional and storage) and human health