TY - JOUR

T1 - Application of Fourier transform mid-infrared photoacoustic spectroscopy for rapid assessment of phosphorus availability in digestates and digestate-amended soils

AU - Huang, Jing

AU - Glæsner, Nadia

AU - Triolo, Jin M.

AU - Bekiaris, Georgios

AU - Bruun, Sander

AU - Liu, Fei

N1 - Publisher Copyright: © 2022 Elsevier B.V.

PY - 2022

Y1 - 2022

N2 - Digestate is the anaerobic digestion by-product of biogas production that can be used as a phosphorus (P) fertilizer. To achieve the efficient utilization of digestate as a P fertilizer and evaluate P availability in digestate-amended soils, it is necessary to assess both available P in different digestates and digestate-amended soils. In this study, Fourier transform mid-infrared photoacoustic spectroscopy (FTIR-PAS) combined with multivariate analysis was applied to predict water-extractable P (WEP) in digestates and plant-available P in digestate-amended soils. The plant-available P was determined by the diffusive gradients in thin films (DGT) technique. 45 digestate samples were collected both from laboratory-scale digesters (26 samples) and operating biogas plants (19 samples) in Denmark for WEP determination. Three soils amended with the collected 19 digestate samples from biogas plants (that results to 57 digestate-amended soil samples in total) were deployed for DGT measurement of plant- available P. The WEP predicting model had a coefficient of determination (R2) of 0.80 and a root mean square error of 0.78 g kg−1 while the plant-available P predicting model exhibited an R2 of 0.70 and a root mean square error of 134.09 μg P L−1. Furthermore, regression coefficients with a significant contribution of the plant-available P predicting model were identified, indicating that FTIR-PAS is capable for correlating spectra information with plant-available P related chemical bonds. In conclusion, FTIR-PAS can be used as a faster and non-destructive alternative for the assessment of both WEP in digestates and plant-available P in digestate-amended soils.

AB - Digestate is the anaerobic digestion by-product of biogas production that can be used as a phosphorus (P) fertilizer. To achieve the efficient utilization of digestate as a P fertilizer and evaluate P availability in digestate-amended soils, it is necessary to assess both available P in different digestates and digestate-amended soils. In this study, Fourier transform mid-infrared photoacoustic spectroscopy (FTIR-PAS) combined with multivariate analysis was applied to predict water-extractable P (WEP) in digestates and plant-available P in digestate-amended soils. The plant-available P was determined by the diffusive gradients in thin films (DGT) technique. 45 digestate samples were collected both from laboratory-scale digesters (26 samples) and operating biogas plants (19 samples) in Denmark for WEP determination. Three soils amended with the collected 19 digestate samples from biogas plants (that results to 57 digestate-amended soil samples in total) were deployed for DGT measurement of plant- available P. The WEP predicting model had a coefficient of determination (R2) of 0.80 and a root mean square error of 0.78 g kg−1 while the plant-available P predicting model exhibited an R2 of 0.70 and a root mean square error of 134.09 μg P L−1. Furthermore, regression coefficients with a significant contribution of the plant-available P predicting model were identified, indicating that FTIR-PAS is capable for correlating spectra information with plant-available P related chemical bonds. In conclusion, FTIR-PAS can be used as a faster and non-destructive alternative for the assessment of both WEP in digestates and plant-available P in digestate-amended soils.

KW - Diffusive gradients in thin films (DGT)

KW - Digestate

KW - Fourier transform mid-infrared photoacoustic spectroscopy (FTIR-PAS)

KW - Partial least squares regression (PLSR) modelling

KW - Water-extractable phosphorus (WEP)

U2 - 10.1016/j.scitotenv.2022.155040

DO - 10.1016/j.scitotenv.2022.155040

M3 - Journal article

C2 - 35385760

AN - SCOPUS:85127747309

VL - 832

JO - Science of the Total Environment

JF - Science of the Total Environment

SN - 0048-9697

M1 - 155040

ER -