Biosolids for the sod business – Audio
Doug Soldat, UW-Extension turfgrass and urban soil specialist
Assistant Professor
Department of Soil Science
UW-Madison College of Agricultural and Life Sciences
djsoldat@wisc.edu
(608)263-3631
3:01 – Total Time
0:19 – A problem with a possible solution
0:48 – soil replacement and fertilizer researched
1:12 – Fertilizer, eyes, soil replacement not so much
1:32 – Biosolid waste is a total fertilizer for sod
1:58 – What are biosolids
2:18 – Sod farms good phosphorous sinks
2:52 – Lead out
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Transcript
Sevie Kenyon: Can you give me an idea what you’ve learned about putting biosolids on sod farm production?
Doug Soldat: Sod farming is a really unique agricultural practice. And when we harvest sod we actually remove a layer of soil. And so you can imagine if you do this for years and years and years, you start to worry about how much soil’s going to be left on the sod farm. So one of the things we’re thinking about is ways to incorporate other products to minimize that export of the soil from sod farms.
Sevie Kenyon: And Doug, what did you learn when you did your research with biosolids?
Doug Soldat: Biosolids are the solid material that’s left over after we treat the waste, and has a really strong nutrient value, but also contains a lot of carbon, and it’s a physical solid. So we thought that we could add the biosolids to the sod farms to help offset the need for fertilizer, and also to replace some of the soil that gets sold off to the consumer.
Sevie Kenyon: What did you learn from doing that exercise?
Doug Soldat: The carbon in the biosolids that we put down doesn’t hang around the soil very long. It goes into the atmosphere. Which is normally where it would end up; we thought that if we put the biosolids into the soil, that some of that carbon would get sequestered and locked into the soil. But we found that actually wasn’t the case.
Sevie Kenyon: Where do you want to go with this research, knowing what you now know?
Doug Soldat: One of the exciting things that we learned was that biosolids can be used as a fertilizer replacement for growing sod. Which means that we can reduce the cost to the growers. We can beneficially get rid of what we normally think of as a waste product; in fact make sod production a more sustainable practice.
Sevie Kenyon: And maybe you can tell us, Doug, where these biosolids are sourced from, what are they?
Doug Soldat: Now biosolids are essentially the solid waste that we generate. So it goes into the sewer; we used to call it sewage sludge, the new term is biosolids, maybe a little bit more confusing, but that’s the term we use. Essentially we are talking about human solid waste.
Sevie Kenyon: Are sod farms an alternative to solid waste disposal now?
Doug Soldat: In Madison, the biosolids are used on agricultural fields. They’re injected into the soil. But one problem with that is that after awhile the phosphorus begins to accumulate, and we know that we want to keep our soil phosphorus levels low to protect the surface water around the state. So what happens is you start to have to drive further and further and further out to find places to put these biosolids. So sod farming, we looked at, is a really good option because you’re removing the sod, and then reducing the amount of phosphorus that accumulates in the soil.
Sevie Kenyon: We’ve been visiting with Doug Soldat, Department of Soil Science, University of Wisconsin-Extension and the College of Agricultural and Life Sciences, Madison, Wisconsin, and I am Sevie Kenyon.