TY - JOUR

T1 - Is wood ash amendment a suitable mitigation strategy for N2O emissions from soil?

AU - Bornø, Marie Louise

AU - Rønn, Regin

AU - Ekelund, Flemming

PY - 2020/4/15

Y1 - 2020/4/15

N2 - Wood ash, the by-product of biomass combustion to energy, can return important nutrients back to the soil and counteract acidification. However, the application of wood ash may affect the emission of greenhouse gases. Here, the effect of wood ash application on nitrous oxide (N2O) emissions from different soil environments were investigated in a 40 days incubation experiment comprising ten different soil types amended with five different wood ash concentrations (0, 3, 9, 20, and 54 t ash ha−1). The emitted N2O was measured continuously, and initial soil properties without ash application (carbon (C), nitrogen (N), ammonium (NH4 +), nitrate (NO3 −), and pH) and resulting soil properties (pH, NH4 +, and NO3 −) were measured prior and after the incubation period, respectively. The Random Forests (RF) model was used to identify which factors (initial and resulting soil properties, vegetation, management, wood ash doze, and respiration rate) were the most important to predict the development of emitted N2O after ash application. Wood ash either increased, decreased, or had no effect on the amount of emitted N2O depending on soil type and ash dose. The RF model identified the final resulting pH as the most important factor for the prediction of emitted N2O. The results suggest that wood ash can mitigate N2O emissions from soil, however, this effect depends on soil type where a mitigating effect of wood ash application was observed mainly in low pH soils with high soil organic matter whereas an increase in N2O emissions was observed in mineral soils that had previously received N fertilization. This study emphasises the importance of pH manipulation in regards to N2O emissions from soil.

AB - Wood ash, the by-product of biomass combustion to energy, can return important nutrients back to the soil and counteract acidification. However, the application of wood ash may affect the emission of greenhouse gases. Here, the effect of wood ash application on nitrous oxide (N2O) emissions from different soil environments were investigated in a 40 days incubation experiment comprising ten different soil types amended with five different wood ash concentrations (0, 3, 9, 20, and 54 t ash ha−1). The emitted N2O was measured continuously, and initial soil properties without ash application (carbon (C), nitrogen (N), ammonium (NH4 +), nitrate (NO3 −), and pH) and resulting soil properties (pH, NH4 +, and NO3 −) were measured prior and after the incubation period, respectively. The Random Forests (RF) model was used to identify which factors (initial and resulting soil properties, vegetation, management, wood ash doze, and respiration rate) were the most important to predict the development of emitted N2O after ash application. Wood ash either increased, decreased, or had no effect on the amount of emitted N2O depending on soil type and ash dose. The RF model identified the final resulting pH as the most important factor for the prediction of emitted N2O. The results suggest that wood ash can mitigate N2O emissions from soil, however, this effect depends on soil type where a mitigating effect of wood ash application was observed mainly in low pH soils with high soil organic matter whereas an increase in N2O emissions was observed in mineral soils that had previously received N fertilization. This study emphasises the importance of pH manipulation in regards to N2O emissions from soil.

KW - Denitrification

KW - Modelling

KW - Nitrification

KW - pH management

KW - Random forests

KW - Soil amendment

U2 - 10.1016/j.scitotenv.2020.136581

DO - 10.1016/j.scitotenv.2020.136581

M3 - Journal article

C2 - 31951843

AN - SCOPUS:85077734116

VL - 713

SP - 1

EP - 9

JO - Science of the Total Environment

JF - Science of the Total Environment

SN - 0048-9697

M1 - 136581

ER -