Effect of municipal and pulp mill effluents on the chemical properties and nutrient status of a coarse-textured Brunisol in a growth chamber

Abstract

Maximizing productive use and minimizing the environmental impacts of effluents require research on application rates. This study evaluated the effect of effluents from a Kraft pulp mill [a final effluent (KPME) and a waste activated sludge (WAS)], a municipality (ME) and tap water (TPW) applied at rates of 1.5, 3 and 6 mm d-1 on reed canarygrass (Phalaris arundinacea L. cv. Vantage) and hybrid poplar (Populus deltoides × P. petrowskyana var. Walker). The two pulp mill effluents significantly increased soluble soil SO4, Na and Cl. Soil solution electrical conductivity (EC) and sodium adsorption ratio (SAR) increased with pulp mill effluents compared with ME and TPW. Soil solution SAR increased from less than 1 to a range of 2.7 to 4.0 for the municipal effluent and 8.4 to 14.0 for the two pulp mill effluents. Soil solution EC increased from 1.1 to 2.3 dS m-1 to a range of 1.8 to 3.4 dS m-1 for municipal effluent and 5.1 to 6.1 dS m-1 as a result of pulp mill effluent applications. Under reed canarygrass, soils had lower concentrations of cations and anions than those under hybrid poplar, suggesting crop uptake and leaching. Thus, salt loadings of soils must be considered when determining application rates of effluents for irrigation. Key words: Electrical conductivity, hybrid poplar, effluent irrigation, sodium adsorption ratio