Nothing wasted: NMU collaborates with farmers to use wood ash

It's not too often the public sector and private sector can work together seamlessly, as they say. But when they do, good things happen. This is the case with the partnership that has formed with Northern Michigan University, area logging concerns, and local agriculture.

 

In 2013 NMU opened up a $16 million biomass plant on campus that produces electricity via wood chips purchased and hauled in from local mills. The wood chips are a byproduct from the mills. In turn, wood ash is created as a byproduct in the biomass plant. And in turn, instead of sending it off the landfill, the university is offering the ash from the wood chips to area farmers as a soil amendment for their fields.

 

Wood ash has a high pH content, much like dolomitic lime used on farms and in gardens. Farmers can use the wood ash from the NMU heating plant as a cheaper alternative to lime to raise the pH in their soil as needed. However, before NMU can offer the wood ash to area farmers they must get the blessing of the Michigan Department of Agriculture, via licensing.

 

"We send wood chips to a lab that burns the wood and tests the resulting ash," says Gisele Duehring, the associate director for facilities and the biomass heating plant. "We make sure there aren't heavy metals present in the ash; we obtain data for calculating the Neutralizing Value (NV). We include this information in our application to the MDA for a liming license; they look at it and go 'That's good.'

 

"Part of our responsibility as a liming license holder is to look at the proposed storage site for the ash," continues Duehring. "The site needs to be secure enough that ash will not wash into a body of water, e.g. a swamp, and change the pH of it. We provide the NV number to the wood ash recipient. As an example, a farmer will test his soil so he knows how much lime to spread per acre. Then he uses that NV number to know how the wood ash compares to lime regarding field application."

 

So far, one local farmer is using the wood ash on his farm and has reported positive results with his crops. Wood ash contains potassium and some trace elements, according to Dan Sullivan, soil scientist with Oregon State University Extension Service. However, the main benefit for farmers is to be able to increase the pH of a soil where it is low, so crops can utilize nutrients, such as nitrogen, more efficiently.

 

The wood ash project has been a learning experience for at least one NMU student. Eric Martin was urged into getting involved in the project by his advisor Suzy Ziegler, head of the Earth, Environmental and Geographical Sciences Department at NMU. Martin helped Duehring apply for the liming license and assisted Curt Goodman, Marquette water/wastewater superintendent, in preliminary research on alternative uses for wood ash and biosolids.

 

"That really interested me," says Martin. "I toured the Ripley Heating Plant and the wastewater treatment plant. Curt and I brainstormed how an experiment could be set up to combine biosolids and wood ash and test the effects on soil remediation."

 

Martin says for a senior project he may create test plots behind the wastewater plant to compare the growth of crops in soil amended with wood ash, biosolids and various combinations of the two to determine the ideal ratio for optimum soil.

 

As for Goodman, he says he'll continue to experiment with the wood ash as he has time to determine beneficial uses for the byproduct. He says he's working with the DEQ on an uncontaminated site, a brownfield, which is hard-packed with iron ore deposits. Goodman says they could use a mix of the biosolids from the treatment plant with the wood ash to grow poplars and willows on the site. 

 

The Ripley Heating Plant on NMU's campus is expected to save the school $300,000 per year in heating costs and is expected to produce close to 90 percent of the energy that would otherwise be supplied by the burning of fossil fuels and more than 15 percent of NMU's electricity purchased from the Marquette Board of Light and Power.

 

NMU president Les Wong says it is part of NMU's strategic plan to consume renewable energy and reduce the university's carbon footprint, which he says also is the message they wish to pass along to students.

 

 It's a win-win situation for all involved:  "It helps the overall economy to have a diverse market," says Duehring of the collaborative effort. 

 

 

If you heat with a wood stove and burn local hardwood or softwood, you've got an abundant supply of a soil amendment for your lawn and gardens.

 

Wood ash contains 13 essential nutrients the soil must supply for plant growth, according to Dan Sullivan, soil scientist with Oregon State University Extension Service. Use it on your lawns, vegetable, and flower gardens, but not on acid-loving plants like blueberries, rhododendrons and azaleas.

 

It is best to test your soil prior to applying wood ash to your lawn or garden. Do not apply if your soil pH is over 7.0 or if there is already excessive potassium in the soil, advises Sullivan. Spread ½ to 1 lb. of wood ash around shrubs and rose bushes annually. Apply no more than 10 to 15 lbs. of the stuff per 1,000 square feet on lawns and 5 to 10 lbs. per square feet in vegetable and flower gardens.