Animal Manure: Water Pollution Threat?

Animal manure is a major source of water pollution, particularly in agricultural areas. Manure contains nitrogen, phosphorus, and pathogens, which can contaminate both surface and groundwater. Excessive application of manure or improper handling can lead to the release of these nutrients into water bodies, causing environmental and health issues. Farms and animal feeding operations must adhere to regulations and implement proper manure management practices to protect water quality and prevent contamination. This includes managing runoff, following application techniques, and complying with local laws to reduce the impact of manure on water resources.

Animal manure contains harmful bacteria, nitrogen, ammonia, and phosphates

Animal manure is a valuable source of nutrients for crops and a beneficial soil conditioner. However, it can also contain harmful substances, including bacteria, nitrogen, ammonia, and phosphates, which can pollute water sources if not properly managed.

Harmful Bacteria

Animal manure can harbour dangerous pathogens, including E. coli O157:H7, Listeria, Cryptosporidium, and Salmonella. These bacteria can contaminate produce if raw manure is improperly handled or applied or if wild or domestic animals have access to growing areas. For example, in one incident, a person died from consuming strawberries grown in a field where deer feces were found, with the same strain of E. coli O157:H7 found in both the deer feces and the affected individuals.

Nitrogen

Excess nitrogen in manure can have negative environmental and human health impacts. Over half of the nitrogen content in manure can be in the form of ammonia, which can be readily lost to volatilisation under hot, aerated conditions. High levels of ammonia in housing facilities can cause lung damage to animals and farmers. Additionally, nitrogen lost through leaching and runoff can contribute to water pollution.

Ammonia

Ammonia (NH3) emitted from livestock manure is a significant concern due to its odour, financial implications through increased fertiliser costs, and potential environmental and human health impacts. Farmers in many European nations and Concentrated Animal Feeding Operations in the US are required to follow ammonia mitigation practices. Proper management of animal diet, housing, manure storage, and land application can help maximise nitrogen retention and reduce air pollution.

Phosphates

Animal manure contains organic and inorganic phosphate compounds. While most soils have a large capacity to retain phosphorous, increasing the amount of phosphorous in soils can lead to small but environmentally important increases in the amount of dissolved phosphorous in water. This can occur through runoff during storm events or when soil phosphorous reaches saturation. Proper management of manure application rates and adherence to nutrient utilisation standards are essential to prevent excess phosphorous levels in water.

Overall, while animal manure has agricultural benefits, it is crucial to implement safe handling, storage, and application practices to prevent water pollution and protect human health.

Manure management techniques to reduce water pollution

Animal manure contains bacteria, nitrogen, ammonia, and phosphates. When it rains, these contaminants can be carried to local waterways by rainwater runoff. Manure can also contaminate groundwater through runoff after excessive land application. As such, it is important to implement proper manure management techniques to reduce water pollution. Here are some techniques to achieve this:

Nutrient Management Planning

This process involves determining the appropriate rates of manure application based on nitrogen content. While phosphorus and potassium are not considered groundwater contaminants from a health standpoint, their runoff can stimulate algae growth in water bodies, negatively impacting water quality. By applying manure at rates that meet crop nitrogen needs, there is a risk of applying excess phosphorus. Nutrient management planning helps balance the application of nitrogen and phosphorus to meet crop needs while minimizing the risk of water pollution.

Phosphorus Index (P-Index)

The P-index is a risk assessment tool that considers various factors to determine if nitrogen-based rates of manure application can be used or if adjustments are needed to phosphorus-based rates. In some cases, the index may indicate a high risk, warranting the discontinuation of phosphorus application. This tool helps farmers make informed decisions to prevent the buildup of phosphorus in the soil, reducing the risk of it being transported into water bodies.

Proper Storage and Application

It is crucial to store and apply manure properly to minimize the risk of water pollution. Avoid spreading manure near creeks, ditches, or other waterways. Store manure on a flat, dry, and impermeable surface away from water sources. Keep storage piles contained, covered, and surrounded by barriers to prevent runoff and contain pollutants. Regularly clean up manure, especially during the wet season, and compost it to reduce volume and create a valuable nutrient source for the soil.

Manure Marketing and Technology

With the consolidation of animal agriculture sectors leading to larger farms, more manure is being produced in smaller areas. Manure marketing involves finding fields within a reasonable distance for manure application. Some farmers are also exploring technologies that can add value to manure, such as solid manure considerations, to prevent spills and manage nutrients effectively.

Compliance with Regulations

Local and state regulations, such as those prohibiting the discharge of manure-laden water into waterways, exist to prevent water pollution. It is important for farmers to understand and comply with these regulations, including groundwater monitoring laws and protocols for groundwater contamination prevention. By adhering to these regulations, farmers can help protect water resources and ensure safe drinking water for their communities.

Manure spills and emergency planning

Animal manure can contain pathogens, antibiotics, and hormones, which can have detrimental effects on human health. For example, microbial pathogens such as Salmonella, E. coli, and enteroviruses can survive in groundwater for at least 400 days and cause severe health issues. Therefore, it is crucial to prevent the spread of these pathogens and avoid contaminating water sources.

To prevent and effectively manage manure spills, it is essential to have a comprehensive emergency plan in place. Manure spills can be caused by various factors, including mechanical failure, improper application, and poor management of storage facilities. By understanding the root causes of spills, farmers can implement effective prevention measures and emergency response plans.

• Understanding Spill Causes: Research and identify the common causes of manure spills in your specific context. For example, equipment failure and storage overflow are among the leading causes of spills. Understanding these causes can help you tailor your prevention and emergency response strategies.
• Implement Prevention Measures: Focus on prevention by conducting regular self-inspections and maintaining accurate records, especially for manure structures, conveyances, and equipment. Properly design, construct, and maintain manure storages according to established standards to ensure stability and safety.
• Develop an Emergency Action Plan (EAP): Create a detailed EAP that outlines the steps to take in the event of a manure spill. The plan should include:

• Eliminating the source of the spill.
• Containing the spill to prevent further contamination.
• Assessing the extent of the spill and noting any obvious damages.
• Notifying the appropriate agencies and emergency services, such as calling 911.
• Cleaning up the spill and making any necessary repairs.
• Preparing and submitting a summary report to the relevant authorities within the required timeframe, typically 7 to 14 days after the incident.

• Train and Inform Employees: Ensure that all farm employees are aware of the EAP and understand their roles and responsibilities in the event of a manure spill. Contractors, equipment suppliers, and local authorities should also be informed of the plan. Regularly review and update the EAP, retraining employees as necessary.
• Consider Manure Type: Recognize that the response method for a spill may vary depending on the type of manure involved. For example, solid manure spills may be easier to manage as they have less movement across surfaces and do not infiltrate like liquids.
• Spill Response Technology: Explore and invest in technology that can help prevent and manage spills effectively. This may include equipment and systems designed specifically for manure spill response and containment.
• Compliance with Regulations: Adhere to local regulations and groundwater contamination prevention protocols. Understand the laws and requirements regarding livestock manure storage and groundwater monitoring in your area.

By implementing these measures, farmers can effectively manage manure spills and minimize their impact on the environment and human health. Proper planning and emergency preparedness are crucial to ensuring a swift and efficient response to manure spills, protecting water sources, and mitigating potential risks associated with animal manure.

Manure application techniques and best practices

Animal manure can be a source of water pollution if not managed properly. It can contain nitrogen, phosphorus, pathogens, antibiotics, and hormones, which can negatively impact human health and the environment. To prevent water pollution, it is crucial to follow best practices for manure application. Here are some techniques and guidelines for effective manure application and management:

Manure Application Techniques:

• Soil and Water Conditions: Understanding soil and water conditions is essential before applying manure. Consider factors such as soil type, moisture content, and drainage. Be cautious with dry and cracking soils, as they can impact manure distribution and increase the risk of nutrient runoff.
• Nutrient Management: Determine the nutrient requirements of your crops. Apply manure based on nitrogen and phosphorus content to avoid excessive nutrient levels in the soil, which can lead to water pollution. The phosphorus index (P-index) is a useful tool for assessing the risk of P-based application.
• Application Timing: Monitor weather conditions and forecasts. Avoid applying manure before heavy rainfall, as it can increase the risk of nutrient loss through runoff and erosion. Consider delaying application if wet conditions are expected.
• Application Methods: Choose the appropriate application method based on the type of manure (solid or liquid). Solid manure is typically spread using broadcasting equipment, followed by tillage. Liquid manure can be applied through surface banding, broadcast spreading, trailing hose systems, or injection methods.
• Equipment Calibration: Ensure that all application equipment is properly calibrated and maintained. Calibration ensures accurate application rates, enhancing the efficiency of manure nutrients and reducing the risk of over or under-application.
• Irrigation Management: When irrigating manure, understand soil infiltration rates to prevent over-application. Continuously monitor irrigation equipment to avoid runoff, which can lead to water pollution.
• Separation Distances: Identify areas where manure application is not allowed. Train employees to read maps and maintain separation distances to comply with regulations and avoid potential environmental hazards.

Best Practices for Manure Management:

• Comprehensive Manure Nutrient Management Plan: Develop a plan that considers the nutrient needs of your crops and the application rates of manure. This helps reduce the risk of environmental problems and optimizes the use of manure nutrients.
• Composting: Consider composting as a valuable approach to manure management. Composting converts raw manure into nutrient-rich soil enhancers, reduces odors, and eliminates pathogens and weed seeds.
• Manure Removal and Storage: Regularly remove manure from animal housing to improve the animal environment and reduce health risks. Store manure properly to prevent spills and contamination of water sources.
• Compliance with Regulations: Stay informed about local regulations and groundwater contamination prevention protocols. Comply with laws related to groundwater monitoring and livestock manure storage to protect water resources.
• Water Testing and Remediation: Test water sources for contaminants, and if contamination occurs, consult experts to find solutions or alternative water sources. Prioritize protecting groundwater and ensuring safe drinking water.

Manure storage and disposal

Animal manure contains nitrogen and phosphorus, antibiotics, and hormones, which can negatively affect human health. Microbial pathogens such as Salmonella, E. coli, and enteroviruses can survive in groundwater for at least 400 days and are harmful to humans. Thus, it is important to prevent the spread of pathogens and other contaminants from manure to water sources.

When storing and disposing of animal manure, it is crucial to follow local regulations and protocols to prevent groundwater contamination. Here are some key considerations and practices for proper manure storage and disposal:

• Storage Facilities: Small farms can opt for stockpiling, dry stacking, composting, liquid storage, or hauling away manure. Stockpiling involves piling solid manure and bedding in a designated location, requiring a compacted and sealed base soil to prevent nutrient leaching. Dry stacking is commonly used for small livestock or horse operations, with an impervious floor and three walls to contain the manure. Composting reduces nitrogen levels, kills pathogens, and improves the marketability of the final product.
• Storage Location: The location of manure storage should be carefully chosen to minimize environmental impacts. Avoid flood hazard areas, steep slopes, and areas prone to runoff. Keep clean water sources separate and divert rooftop or surface runoff away from the storage area.
• Containment and Treatment: To prevent nutrient leaching and groundwater contamination, use vegetated filter strips or storage ponds lined with compacted clay soil, concrete, or artificial liners. Contain and treat dirty water to prevent pollutants from entering water sources.
• Storage Capacity and Design: The capacity of manure storage depends on waste volume, retention time, and the potential impact of precipitation. Storage structures can include earthen pits, holding ponds, treatment lagoons, above-ground or below-ground tanks, and concrete structures.
• Nutrient Management: Develop a comprehensive nutrient management plan to optimize the use of manure nutrients and reduce environmental risks. The phosphorus index (P-index) is a risk assessment tool that helps determine appropriate manure application rates based on nitrogen and phosphorus content.
• Application and Timing: Improper application of manure, such as excessive rates or incorrect timing, can lead to nutrient losses and pollution. Apply manure based on crop requirements to prevent excessive nitrogen and phosphorus levels in the soil and water.
• Compliance and Monitoring: Adhere to local regulations and groundwater monitoring laws to ensure compliance with contamination prevention protocols. Regularly test water sources for contaminants and take corrective actions if contamination is detected.

Frequently asked questions