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Researchers from the University of Wisconsin Oshkosh will lead a webinar next month discussing the pros and cons of soluble salts related to the compost industry.

Soluble Salts: Are They Good or Bad? will be presented at 1 p.m. (CST) Wednesday, Dec. 9, as a webinar.

During the webinar, participants will learn what a research team from UW Oshkosh discovered during their extensive look at available scientific research and hear about the next steps taken to get the work peer-reviewed and published.


Speakers will be Greg Kleinheinz, UWO engineering technology department chair; Carmen Thiel, manager of the Environmental Research and Innovation Center lab at UWO; and Ginny Black, Composting Council Research and Education Foundation trustee chair and president of Black Gold Recycling LLC.

Kleinheinz said the purpose of the soluble salt literature review was to gather the available peer-reviewed scientific research regarding the salt content of finished composts causing the high concentration in soils. The goal was to identify the specific types of salts and whether those salts are beneficial or harmful to plant growth.

Kleinheinz noted the compost industry has met with resistance to the use of finished compost because of high electrical conductivity measurements of soluble salts. He believes soluble salts are the most misunderstood parameter in a compost test data report.

Many specifiers assume all soluble salts are harmful to plant growth and that soluble salts in compost directly translate to negative plant response.

“This leads to compost specifications based on this assumption and results in overly narrow soluble salt ranges for compost use,” he said. “What is not understood is that soluble salt is a total number assigned to an entire category of charged elements found in compost and include parts of the NPK (nitrogen, phosphorus, potassium), micro and macro nutrients beneficial, even essential, to plant growth.”

The event is sponsored by WeCare Denali, one of the largest composters in the U.S.

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