West-Central Forage Association

Pulp Mill Sludge v. Dry Fertilizer

Sludge pile.jpg

Pulp Mill Sludge vs. Dry Fertilizer on Perennial Forages

This five year demonstration trial will observe perennial forage species growth and assess soil quality when two different fertilizer products are applied: mechanical pulp mill sludge and dry fertilizer. The project is being conducted at the already established perennial forages site in Woodlands County. The site is located near the Anselmo hall and was seeded in 2014. 


To observe the changes in soil biota and chemistry when comparing dry fertilizer and pulp mill sludge over 5 years. To compare forage yield and quality between the fertilizer and pulp mill sludge application. 


Marleen Audrey


Trial Information

The site is located in Woodlands County at SW-32-56-10-W5 (near Anselmo Hall). The site was seeded to a prepared seedbed on June 23th, 2014 using a small plot Fabro disc seeder. 

5 varieties of each perennial forage were seeded (each variety was replicated three times), with the exception of Birdsfoot Trefoil (one variety replicated five times). Forages used were: 

  • Alfalfa
  • Brome
  • Cicer Milkvetch
  • Clover
  • Orchardgrass
  • Reed Canarygrass
  • Ryegrass
  • Sainfoin
  • Timothy
  • Birdsfoot Trefoil

In 2017 WCFA began a five year demonstration trial to assess growth differences, as well as soil health effects when applications of either pulp mill sludge or dry fertilizer were applied. Each forage received 5 treatments of pulp mill sludge, 5 treatments of dry fertilizer and 5 control treatments (no application). 

Pulp mill sludge was applied at a rate of 25 tonnes/ha, as per the recommendation, and will be reapplied every two years. Dry fertilizer was applied at the recommended rate from the soil tests for both the legume species and the grass species, and will be applied yearly. Both treatments were applied on July 24,2017. 

Soil tests were done prior to the application, and will be continued throughout the duration of the project. Yield and quality analysis were also completed in August, and will continue throughout the duration of the project. 

2017 served as the establishment year, and all data collected will act as the baseline for future comparison. As the project continues, reports will be made available.