Demonstrating composting with paper mill residuals – Part 2

Paper mill residuals are a soil amendment available to farmers in Michigan’s Upper Peninsula.

Equipment used to spread paper mill residuals on the farm fields. Photo by Monica Jean, MSU Extension.

Paper mill residuals, commonly referred to as mill sludge, are a product of the wastewater treatment process of wastepaper recycling, wood pulping and papermaking. Michigan State University Extension coordinated and carried out a demonstration trial in Michigan’s Upper Peninsula to investigate the feasibility of composting paper mill residuals with manure.

Two equal volume piles were created with the residual and manure provided by the cooperating farm in Pelkie, Michigan. The three treatments included a pile of one part residual and two parts manure (1R2M), a pile of one part manure and two parts residual (2R1M) and a pile of manure. The manure was a bedded beef pack of manure and straw. The summary of lime and nutrient content of the composted material is available in “Demonstrating composting with paper mill residuals - Part 1.”

The composted residual piles and manure pile were applied in replicated strips to a hay field in early May at a rate of 6 tons per acre. The hay was then mowed and dried on July 2 with sample collected on July 5. Yield was reported on a dry matter per acre basis (Table 1) and showed no statistical difference between the composted manure and two residual blends. The average yield of the field in the non-treated areas was 1.78 dry matter tons per acre. The cooperating farm owner noted a visual improvement of the fields with all applied treatments.

Table 1. Summary of average dry matter yield per acre for the composted manure, composted one part residual and two parts manure (1R2M) and composted one part manure and two parts residual (2R1M).


Average dry matter yield per acre







*No statistical difference between the treatment means.

In conclusion, the addition of the residual did contribute lime, but all of the treatments contributed organic matter. A change in the soil health that would improve growing conditions can take many years to achieve. Additional research of quality analysis and multi-year approach may show some significant difference between treatments.

For questions and inquires, contact Monica Jean at 906-786-3032 ext. 106 or

For more information, see these related articles from MSU Extension:

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