The impacts of aerated compost teas on trees, soils, and the environment

2008 | Bryant Scharenbroch, The Morton Arboretum, Illinois

Aerated compost tea (ACT) is gaining interest as a nutrient amendment for urban trees. This study examined the effects of ACT, synthetic fertilizer, and deionized water on 15 biochemical properties with two soil types. Significant effects for pH, Mg2+, Na+, C, N, and C/N ratio were not observed among treatments. No differences between dilute ACT (ACTd) at 22.4 kL ha-1 and water were detected. Soil K+ was greater with ACT concentrate (ACTc) at 224 kL ha-1 compared to 30-10-7 fertilizer at 195 kg N ha-1 with A horizon soils. Soil K+, NH4+, and microbial respiration were greater with ACTc compared to water in A soils. Soil P (A soils only), NO3- (Bt soils only), dissolved organic N, microbial biomass N, and N mineralization were greater with fertilizer compared to ACT. Increases in denitrification were seen with ACTc compared to fertilizer and water in the first 24 hours (+4 to +12 mg N2O kg-1), but greater increases were observed with fertilizer at hours 48 and 96 (+65 to +127 mg N2O kg-1). Greatest improvements in soil fertility were observed with fertilization. Minor improvements in soil fertility were observed with ACTc, and denitrification losses were lower with ACTc compared to the fertilizer.

Year: 2008

Funding Duration: 3-5 years

Grant Program: Hyland Johns

Grant Title: The Impacts of Aerated Compost Teas on Trees, Soils, and the Environment

Researcher: Bryant Scharenbroch


Key words: aerobic compost teas (ACT); fertilization; microbial activity; microbial biomass; nitrous oxide; nutrient availability; synthetic fertilizer

Peer Reviewed Publications from Grant:

  • Scharenbroch, B.C., M. Catania, W. Treasurer, V. Brand, V. 2011. Lab assays on the effects of aerated compost tea and fertilization on soil biochemical properties and denitrification in A and Bt horizon soils. Arboriculture and Urban Forestry. 37:269-277 View the Publication >

General Audience/Trade Publications: none

Presentations: none

For more information on this project, contact the researcher via TREE Fund at