Greenhouse gas emissions following land application of pulp and paper mill sludge on a clay loam soil
Citation
Faubert, P., Lemay-Bélisle, C., Bertrand, N., Bouchard, S., Chantigny, M.H., Durocher, S., Paré, M.C., Rochette, P., Tremblay, P., Ziadi, N., Villeneuve, C. (2017). Greenhouse gas emissions following land application of pulp and paper mill sludge on a clay loam soil. Agriculture, Ecosystems and Environment, [online] 250 102-112. http://dx.doi.org/10.1016/j.agee.2017.07.040
Plain language summary
Paper mill residues are used in agriculture as organic fertilizers and because of their positive effects on soil quality. Knowledge of greenhouse gas emissions associated with the use of paper mill residues in agriculture is however scant. A field study was conducted over two consecutive years to quantify emissions of nitrous oxide (N2O), a potent grenhouse gas derived from fertilization of soils, and to compare with emissions arising from the use of a popular commercial fertilizer in Canada: urea. Crop yields were similar between paper mill residues and urea. On average, N2O emisisons were similar between paper mill residues and urea. However, emissions were generally lower with paper mill residues in dry periods whereas emissions were greater with the residues in wetter period. In conclusion, even though crop yield and average greenhouse gas émissions from the field are not expected to change where urea is replaced with paper mill residues, more research is required to determine best management pratices to abate global greenhouse gas emissions associated to fertilization of agricultural soils in Canada.
Abstract
Pulp and paper mill sludge (PPMS) is applied on agricultural soils as an organic fertilizer. Although it is well accepted that land application of PPMS has benefits for soils and crops, information on PPMS-induced soil N2O emissions is still limited. We assessed the effect of substituting mineral N fertilizer for PPMS on soil N2O emissions after a single application at planting on a clay loam cropped to wheat (Triticum aestivum L.) over two snow-free seasons in eastern Canada. Fertilization treatments consisted of 0, 25, 50, 75, and 100% of crop N requirements derived from N supplied by PPMS, the remaining N being supplied as urea-N. Soil CO2 and CH4 emissions were also measured and not affected by the fertilizer addition; a slight CH4 oxidation occurred. Area-based N2O emissions from PPMS fertilization (4.4 to 12.1 kg N2O-N ha−1) were similar or higher than from urea alone (3.4 and 6.2 kg N2O-N ha−1). Although crop yields were not affected by the type of fertilizer, yield-based N2O emissions, N uptake efficiency and N surplus (applied N minus aboveground N uptake in crop biomass) indicated that N availability from the mineral fertilizer was higher than from PPMS for the wheat crop. However, treatments with PPMS had fertilizer-induced N2O emission factors (FIEF, applied N lost as N2O-N; 0.8 to 3.1%) similar to urea alone (−0.3 and 4.5%). Although substituting urea-N with PPMS in agricultural fields might reduce N2O emissions under moderate soil moisture conditions, PPMS land application produced greater N2O emissions under high soil moisture conditions. Further research on a variety of agricultural practices is needed before concluding that including PPMS in the fertilization plan could result in a global GHG abatement as compared to mineral fertilizers under the cool climate of eastern Canada.