ON THE MOVE
WHEN AND WHERE DO MANURE SPILLS OCCUR? A study of incident reports over the years revealed some manure spill trends. by Reed Kostelny
M
anure spills are a real obstacle for any livestock operation and any custom applicator. They may stop application for the day or require outside equipment to be hired for quick cleanup. Adding together the troublesome time costs and environmental impacts of manure spills, it is always worthwhile to look for ways to avoid them. As an intern for University of Wisconsin-Madison Extension’s Conservation Professional Training Program, a previous intern (Racheal Osterhaus) and I researched manure spills and runoff incidents that happened in Wisconsin over a five-year period (2015 to 2019). We were looking for common issues and improvements that could be made. By looking through paper and electronic files kept by the Wisconsin Department of Natural Resources (WDNR) and county agencies, 729 spills were found. While evaluating these spills, we focused on collecting information about the root causes, impacts, and the commonalities between spills.
Where spills occur The first piece of data to look at is where these manure spills take place. We broke the spills into three categories: 1. During transport 2. On the farm 3. During or after application Spills most often happened when manure was being transported from the
Figure 1. Where did the manure spills occur? 50%
■ 2015 to 2019
30% 20% 10% 0% Farm
Transportation
Land application
The proportion of all spills that occurred in each location in both five-year periods. Spills with unknown locations were less than 1% of the total. N=520 for 2010 to 2014 and N=729 for 2015 to 2019.
farm to the field (Figure 1). Problems during transportation include incidents like tankers tipping over, accidental valve openings, and dragline leaks. Transportation events have become more frequent, with transport being a cause in 38% of all spills from 2015 to 2019. That was up from 31% between 2010 and 2014. On-farm spills followed closely behind in number of incidents, and between 2015 and 2019, this category represented another 38% of spills. Examples of these would be a manure storage overtopping, barnyard runoff, and transfer pipe failures. This is a smaller percentage of spills when compared to the 2010 to 2014 period, when 40% of spills occurred on the farm. The final location for spills to happen was during or after land application.
18 | Journal of Nutrient Management | November 2021
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■ 2010 to 2014
40%
This is where problems like equipment breakdown or malfunction and runoff due to rain or snowmelt can occur. Overall, the percent of all spills from land application declined. From 2010 to 2014 land application represented 27% of incidents, but it fell to 23% of all spills from 2015 to 2019. Location was unable to be determined for the remaining 1% of manure spill incidents.
Tools and training Extra focus on particular problems can help prevent spills. On-farm issues, like a manure storage overtopping, can be prevented with frequent monitoring of manure levels, equipment maintenance, and diverting as much clean water away from the manure storage as possible. In a previous study (2005 to 2009), jofnm.com
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