Manure management is a diverse topic with approaches that vary by farm. Luckily, this year’s Manure Monday sessions organized by the Ontario Ministry of Agriculture, Food and Rural Affairs (OMAFRA) took on a breadth of topical manure management issues and called on a host of experts to share their specialty knowledge.
Here are a few insights gathered from three series’ webinars, presented throughout the month of March. The webinars covered here are “Emerging technologies for sand-laden manure,” “Manure application logistics and field strategies” and “Manure additives,” respectively.
An introduction to sand separating systems and their uses
Despite being considered the gold standard for cow comfort and cleanliness, widespread adoption of sand bedding has led to the accumulation of sand-laden manure in fields. This increase in application of sand to the soil tends to have negative consequences on its compaction, water infiltration rate, soil texture and water-holding capacity.
Emerging technology out of Denmark is facilitating the separation of sand from sand-laden manure during manure management. This minimizes the sand that ends up in soil, while also allowing sand to be safely recycled for bedding and makes the passage of manure through other manure management systems like an anaerobic digester much simpler, reducing the wear and tear on these systems and other manure-handling equipment.
Using an agitator, macerator and cyclone, sand-manure separator systems remove debris and sand from raw manure, creating an output of de-sanded manure which still contains fibre and organic materials, and washed sand. Of the sand sent through the system, up to 92% is retained and 99% is suitable for reuse.
Constraints of these systems include freshwater usage, which at Wisconsin’s Trillium Hill Dairy – one of three U.S. dairies currently employing the Stjernholm sand separation process – is up to nearly 13 litres of water per cow per day.
However, one dealer noted there is potential to reduce this consumption to as low as 3.8 litres soon. “We are working with all of our dairies right now doing different things to clean water to utilize parlour water or something from the milkhouse, or even clean our own wastewater from the system,” explained Mark Misch, a representative from MAC Contractors, a Wisconsin-based dealer of sand separation systems and other farm services.
Additionally, maintenance demands can be a limiting factor with sand separation, as bi-weekly scheduled six-hour maintenance calls are required and a producer maintenance routine requires a farmworker to spend roughly 30 minutes on the system each day.
Other attributes of the implementation of a sand-separating manure system include reduced electricity costs and consumption due to improved efficiency; a digital control system that allows for remote, whole-system monitoring and trend tracking; and exceptional longevity and durability of the system, which can function for more than 10 years without the need for significant repair.
Strategies for a more efficient manure application
During the second Manure Mondays webinar, two custom manure applicators – Larry Bearinger and Ron Bults – offered a few tips they use to ensure a more efficient manure application:
- Avoid a “one-size-fits-all” approach, Bearinger advised. To do so requires looking at each individual field to determine the most efficient spreading angle, rather than relying on the standard 45-degree positioning. Adapting to the contours and size of each field ensures even coverage and reduces over-application, thereby minimizing runoff.
- Consider investing in a hose humper – a hitch attachment which features a dual-function hose manipulator that can either freely rotate to assist movement or lock to drag equipment, simplifying hose manoeuvring. Furthermore, this attachment helps facilitate more precise turns, enabling manoeuvres like “hockey stick turns” to minimize missed areas and reduce soil compaction. The attachment also permits the use of less hose for the same application area.
- Better hose management, achieved with a hose humper and overhead or underground pipelines, not only conserves physical effort but also significantly boosts operational efficiency. By reducing the need for manual hose resets and allowing for continuous operation, Bearinger reported a gain of up to three additional hours of productive work per day without extending work hours, translating into tangible increases in daily income for his business.
- Practice good communication. Whether you work with a custom applicator or your farm team to spread manure, consistent and clear communication is the best way to achieve the results you seek. “[Discuss] what works best for all parties,” Bults recommended.
How to get the most out of manure additives
To make the most out of manure additives, start with a clear understanding of the purpose of selecting and utilizing them. Common reasons for using additives include sludge breakdown, reduced crusting, foam control, ammonia retention, nutrient capture and odour control. Knowing the specific goals you want to achieve will help you choose the most suitable additives for your farm's needs.
From Iowa State University assistant professor Daniel Andersen, here are four factors to consider before selecting and utilizing a manure additive:
- Watch out for competing additives and focus on a single goal. “Many times, there are competing reactions; it's hard to do everything … it's hard to sometimes achieve all of [your] objectives and you need multiple mechanisms to make them happen,” Andersen explained. By selecting a manure additive to achieve a single goal, the risk of multiple mechanisms canceling each other’s effects is diminished.
- Apply microbial additives early on. The impact of microbial additives on manure is difficult to predict, so starting early (i.e., right after agitation or movement) ensures the best results if your goal is to alter the microbial community of stored manure.
- Consider how the additives are being applied. The effectiveness of manure additives can be optimized through application techniques like adding biochar during agitation to leverage its absorption properties and reduce ammonia loss. Furthermore, paying attention to the impact of pH can help minimize unintended results like increased solids.
- Understand the benefit you seek and how it aligns with other stakeholders’ goals. "We all want a product to do something, but we may want it to do different things," Andersen noted on the potential conflicts around selecting a manure additive. For example, a producer and their neighbour may have competing interests, and decisions may need to be made about the value of collective benefit compared with farm benefit. This will be increasingly important as carbon markets expand and stakeholders seek to capitalize on opportunities for reducing emissions and improving farm sustainability. As the role of manure additives evolves, a crucial step will be to continuously engage with fellow producers, researchers and industry experts to exchange insights and best practices regarding their use.
