Usual and unusual CIELAB color parameters for the study of peat organic matter properties: Tremoal do Pedrido bog (NW Spain)

[摘要] We have tested the practical application of color measurements in the study of organic matter properties (C and N content, C/N ratios, degree of peat humification-DPH) of a 335 cm long peat core sampled at Tremoal do Pedrido bog. Usual and unusual CIELAB color parameters were measured on samples that were sectioned at high resolution (slices of 1 cm in thickness). The objective of the study is twofold: (i) describe a rapid, cost-effective and non-destructive method of assessing peat properties without the need of extractions and chemical methods and (ii) contribute to further research on applied colorimetry using the well-known CIELAB coordinates: L∗, a∗, b∗, C∗aband hab('usual CIELAB color parameters') and the less well-known CIELAB parameters: [a∗ x b∗], [a∗/b∗], [(a∗/b∗) x 1000], [1000 x a∗/(L∗+ b∗)], [2000 x a∗/(L∗ x b∗)] and RLab= [a∗(a∗2+b∗2)1/21010]/(b∗ x L∗6) ('unusual CIELAB color parameters'). Our findings show that L∗ and habcoordinates as well as [(a∗/b∗) x 1000], [2000 x a∗/(L∗ x b∗)] and RLabparameters give the best bivariate Spearman's correlations. Linear regression equations were calculated to predict peat properties from all CIELAB parameters under study and a notable fit (R2: 0.65-0.79) was obtained. The evaluation presented here indicates that the determination of usual and unusual CIELAB parameters offers potential for the study of peat organic matter properties and encourages the routine application of this methodology on other peat cores and organic soils.

[发布机构] Departamento de Edafoloxía e Química Agrícola, Facultade de Farmacia, Universidade de Santiago de Compostela, Santiago de Compostela; 15782, Spain^1;Departamento de Edafoloxía e Química Agricola, Facultade de Bioloxía, Universidade de Santiago de Compostela, Santiago de Compostela; 15782, Spain^2;Laboratory of Applied Microbiology, School of Engineering and Applied Sciences, Harvard University, 58 Oxford St., Cambridge; MA; 02138, United States^3

[关键词] Chemical method;CIELAB color;CIELAB coordinates;Color measurements;Cost effective;High resolution;Linear regression equation;Nondestructive methods