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Can alkaline residuals from the pulp and paper industry neutralize acidity in forest soils without increasing greenhouse gas emissions?

Authors :
Royer-Tardif, Samuel
Whalen, Joann
Rivest, David
Source :
Science of the Total Environment. May2019, Vol. 663, p537-547. 11p.
Publication Year :
2019

Abstract

Abstract Alkaline residuals, such as wood ash and lime mud generated from pulp and paper mills, could be recycled as liming agents in sugar maple (Acer saccharum Marsh.) forests affected by soil acidification. The objectives of this study were (1) to evaluate soil chemistry, in particular soil acidity, after the application of three alkaline residuals from the pulp and paper industry, and (2) to determine if these alkaline residuals altered soil greenhouse gas (GHG) emissions as a result of the change in soil pH or due to their chemical composition. Soil properties and GHG fluxes were monitored for two years after alkaline residuals were applied to six forest sites dominated by sugar maple in southeastern Quebec, Canada. Each site received six treatments: wood ash applied at 5, 10 and 20 t ha−1, lime mud (7.5 t ha−1), a mixture of slaker grits and green liquor sludge (7 t ha−1) and an unamended control. These treatments had acid-neutralizing power from 0 to 9 t ha−1. All alkaline residuals buffered soil acidity as a function of their neutralizing power, and more neutralization occurred in the forest floor layer than in the underlying mineral soil. In the forest floor, the alkaline residual treatments significantly increased pH by more than one unit, nearly doubled the base saturation, and reduced exchangeable acidity, Al and Fe concentrations compared to control plots. The CO 2 and N 2 O fluxes were lower after application of alkaline residuals, and this was related to the soil pH increase and the type of alkaline residual applied. Lime mud was more effective at reducing GHG fluxes than other alkaline residuals. We conclude that these alkaline residuals can effectively counteract soil acidity in sugar maple forests without increasing soil GHG emissions, at least in the short term. Graphical abstract Unlabelled Image Highlights • Alkaline residuals are potential liming agents for acidified sugar maple forests. • Soil pH after liming is explained by the neutralizing power of alkaline residuals • More neutralization occurred in the forest floor layer than underlying mineral soil. • Greenhouse gas fluxes were lower after application of alkaline residuals. • Reduction in greenhouse gas fluxes was related to the increase in soil pH. [ABSTRACT FROM AUTHOR]

Details

Language :
English
ISSN :
00489697
Volume :
663
Database :
Academic Search Index
Journal :
Science of the Total Environment
Publication Type :
Academic Journal
Accession number :
134849977
Full Text :
https://doi.org/10.1016/j.scitotenv.2019.01.337