Managing agricultural wastes such as manure, spent silage, culled fruits and vegetables, and other organic residuals can be a significant burden to farming and greenhouse operations. As agricultural wastes increase on-site, so do the potentials for plant and animal pathogens to persist and become a serious problem to production.
Improperly managed piles can also become noxious and pose serious threats to soil and water quality. As a result, governmental agencies require specific and often complex storage, handling and disposal procedures for various waste materials. Handling procedures become even more rigid for organic production systems. However, if the material is managed successfully, then what was once a problematic waste product becomes a valuable agricultural resource.
Since farming and greenhouse operations and the wastes they generate can be quite variable, it is helpful to approach waste management on a case-by-case basis. However, there are some general issues, considerations and strategies associated with agricultural waste management that can be applicable for most growers.
Agricultural Waste Risks
• Plant and animal pathogens
• Ground- and surface-water contamination
• Noxious odors
• Complex handling and disposal procedures
• Volume and space requirements
• Time, energy and labor requirements
Assessing Your Capabilities
Since waste materials and farming operations differ from one location to the next, it is best to develop a management strategy that fits your specific agricultural operation. The list below provides several key considerations for determining whether on-site or off-site agricultural waste management is best and assessing whether or not you are adequately equipped.
• Volume/tonnage of material: What is the current or expected volume or tonnage of material? This will affect your equipment needs, potential location for processing and storage options.
• Location: When choosing the location for handling and processing, you should consider space for operating equipment, proximity from waste source and soil or structural conditions.
• Storage: Storage of materials heavily depends on the volume or tonnage. Vessels of various sizes, concrete pads, pliable and structural covers, or simply allocating floor space are a few options for storing materials when not being processed.
• Equipment needs: The processing strategy (see below) and amount of material will determine your equipment needs such as shovels, bucket loaders, structures for containment, liquid or air pumps, manure/compost spreaders, and trucks for hauling materials.
• Odor and leachate prevention: These unwanted components are frequently the cause of complaints and management failures. Excess moisture can often lead to odor and leachate problems. Choosing prevention techniques will depend on the management strategy, but in all cases, considerable attention should be given to moisture management.
• Disposal or usage of processed materials: End-products can be used on- or off-site. If using on-site, consider the equipment needs for how the material will be applied in the field, greenhouse, or elsewhere. Trucks for hauling material are needed if it is to be moved off-site as well as pre-determining a reliable destination.
A number of management options are available for farm and greenhouse operations. Keep in mind the end goal of your management plan: either to produce a valuable resource for plant production or volume reduction. Ultimately, time, money and existing capabilities are going to be key determining factors in which strategy will be right for your farm.
• Composting (windrow, static piles, etc.): Materials can be continuously added in windrows or processed in batches. Oxygen is a key component. Often, materials will need to be turned by hand or using machines in order to add oxygen or else oxygen can be added using air pumps.
• Anaerobic digestion: Anaerobic digesters come in various shapes and sizes but this process relies on the lack of oxygen for digestion. This process can be continuous or completed in batches. Equipment and energy needs may be greater for anaerobic digestion than composting but the advantage is reduced time and greater volume reduction.
• Vermicomposting: Also known as worm composting, vermicomposting occurs at room temperature using specific worms (e.g. Eisenia fetida) and microbial activities. Having adequate space to process all agricultural waste materials is often the limiting factor in vermicompost systems; however, the process can be completed in-doors, all year round, and the final material usually has greater value than typical compost.
• Off-site processing: When space is lacking, an off-site location or a commercial facility are alternatives for processing waste materials. Commercial facilities vary in size and the materials they can handle. Tipping and hauling fees are to be expected but the advantage is reduced time, labor, and energy needs for processing on-site.
Whatever your choice, the success of the management strategy should be evaluated periodically during the year as well as each component (collection, processing, hauling, etc.) to ensure efficiency and cost effectiveness.
Compost Production Specialist
Pennsylvania Farm Link, Inc.
Division Chief for Economic Development
PA Department of Agriculture