Manure can be a valuable resource or a liability, especially at dairy farms, where cows produce lots of it. For years, farms have recycled manure nutrients, turning them back into feed and forage for cows by applying them as fertilizers to support crop production. However, handling and applying manure efficiently and sustainably can be challenging. Recent advancements in manure application methods, particularly in-season techniques, have the potential to transform how dairy farmers can utilize this resource to its full potential. This article explores why dragline application is a cost-effective choice for dairy farms and highlights the promising future of in-season application methods.
The value of manure: Nutrients and beyond
Manure is a rich source of nitrogen (N), phosphorus (P) and potassium (K). Add organic matter, which can help soil structure and water retention, and you have a potential asset. Farmers must manage when and how manure is applied to maximize these benefits. Poor application timing or inefficient application methods can lead to nutrient losses, environmental harm, wasted resources – and excess application costs.
While manure nutrient concentrations vary regionally and with farm-specific manure practices, a typical slurry dairy manure may have 25 pounds of N, 11 pounds of P2O5 and 33 pounds of K2O for a potential nutrient value of around $30 per 1,000 gallons. Collecting the value requires making transport, application and logistical decisions that minimize application costs and take advantage of the nutrients as best as possible.
Traditional manure application methods often involve large tanks transporting and spreading manure across fields. While effective for spreading high volumes, tank applications can be expensive and labor-intensive. More explicitly, no matter the application rate, the cost per gallon stays constant as most of the time is spent loading and traveling to and from the field and manure storage. Enter dragline application, a method particularly suited to the higher application rates typical on dairy farms. As umbilical systems eliminate road time and pumping flow rates can be adjusted, higher-rate applications will typically cost less per gallon.
Dragline application: A cost-effective solution
Dragline systems use hoses to deliver manure directly from storage to the application field. This system eliminates the need to haul manure with tanks, reducing fuel costs, road wear and labor demands.
For dairy farms, where manure volumes are large and application rates can exceed 10,000 gallons per acre, there are also potential cost savings associated with using draglines rather than tanks. There can be challenges, though, mainly if the manure is sand-laden or application fields aren’t near each other, so the mainline must be frequently rerun in different directions.
Sometimes, tanking to an in-field load station and using a dragline for the final application may be beneficial.
To help illustrate how application decisions impact manure application costs, Figure 1 provides estimated costs of manure application with manure tanks and umbilical manure application systems based on responses from over 100 commercial manure application businesses in Iowa.
The next frontier: In-season manure application
While dragline systems are effective, in-season manure application methods present an even greater opportunity for optimizing nutrient use and reducing environmental impacts. Applying manure during the growing season – when crops actively take up nutrients – minimizes nutrient losses to runoff or leaching and improves nitrogen use efficiency.
In-season application aligns nutrient availability with crop demand, leading to better yields and reduced dependence on synthetic fertilizers. For dairy farms, where manure is an ongoing byproduct, in-season application provides a way to spread workloads evenly throughout the year and better use manure storage capacity. Figure 2 summarizes work on fertilizer application timing in Minnesota, where fertilizer was either fall, spring or applied at least in part during the growing season (side-dress). While weather causes significant variation in the results in any specific year, on average, the results showed that nitrogen fertilizers applied closer to crop growth improved nitrogen use and increased yields, especially at lower nitrogen application rates.
Similarly, more frequent manure removal is a key strategy for dairy farmers to limit methane emissions from manure, aligning with the Innovation Center for U.S. Dairy’s 2050 pledge to be carbon neutral. When manure is left in storage for extended periods, it undergoes anaerobic decomposition, which produces methane. By removing manure more frequently, farmers can interrupt this process, reducing methane generation. This practice enhances environmental stewardship and positions dairy farms as proactive contributors to the sustainability goals of significant industry leaders like Nestlé, who are committed to lowering the carbon footprint of dairy products. Reducing methane emissions through better manure management is a tangible way for farmers to showcase their dedication to climate-friendly practices and support a carbon-neutral future for the dairy industry.
Automation and innovation for in-season application
Recent work has demonstrated several methods of moving manure application into the crop-growing season (Figure 3). Options that have been pursued include side-dressing onto growing corn using slightly modified umbilical application methods. While effective, this method requires corn to be side-dressed before V4 to minimize injury as the hose is pulled over the growing corn. Working with this premise, companies have devised ways to reduce injury to corn by laying a hard hose between rows of corn during one trip across the field and rewinding it during a return trip on adjacent rows, allowing application until the crop is approximately 3 to 4 feet tall (one such example is the Cadman CMA system). Other companies have followed suit, extending the manure application window by designing high-clearance application equipment with drops that help place the manure near crop roots while winding and unwinding application hoses.
Research shows that all of these options provide the potential to improve nitrogen use while simultaneously reducing manure methane emissions. Moving manure applications to in-season typically means drier soils at the time of application and less compaction risk. It also takes what once was a liability of dairy manure, the water content – and at least in specific locations, makes it an asset as it facilitates beneficially using the water to support crop production. Such application flexibility can improve yields and reduce the risk of nutrient losses by minimizing exposure to weather events and water movement.
However, careful consideration will need to be given to capital costs for each equipment type and how it impacts labor and other manure application costs. Yet the evidence is clear – the potential for more significant revenue and sustainable management exists.
Conclusion
Manure can be a powerful tool for enhancing soil fertility and crop production if managed effectively. Dragline systems provide a cost-effective and efficient solution for dairy farms to lower application costs. In-season application methods like side-dressing with conventional equipment, using a hard hose application system or switching to a high-clearance system represent the next frontier in sustainable manure management. By exploring these innovations, dairy farmers can improve nutrient use efficiency, alter labor demands and lower their carbon footprint – all while supporting higher crop yield.
