The usefulness of the Munsell colour indices for identification of drained soils with various content of organic matter

Abstract

Purpose The aim of the study was to determine the usefulness of the Munsell colour indices for identification of drained soils with various content of organic matter, developed on the sandy substrate. Methods The analysed soils, according to the Polish Soil Classification (PSC 2019), belong to thin murshic soils (WRB 2022: Murshic Histosols/Histic Gleysols), typical semimurshic soils (Mollic/Umbric Gleysols (Arenic, Drainic, Mulmic)) and to postmurshic soils (Umbric Gleysols (Arenic, Drainic, Nechic)). The following dry colour indices: value (V), chroma (Ch), V+Ch, V+0.5Ch, V×Ch and V/Ch, were correlated with soil variables (LOI, Corg., Ntot., C:N and FeHCl, MnHCl—elements extracted with 0.5 M HCl). Results The strongest correlation with the SOM content was displayed by the Munsell value, which allows one to estimate the SOM, Corg., Ntot. content in the soils studied. The classification and regression trees (C&RT) revealed that the analysed soil materials could be successfully divided based on the Munsell value alone. The V/Ch quotient demonstrated significant correlations with LOI, Corg., Ntot., C:N, FeHCl and MnHCl. This quotient equalled 1–2 for murshic (≥ 12% Corg.) and semimurshic (≥ 6.0 Corg. < 12.0%), but varied greatly (1–5) for postmurshic (≥ 0.6 Corg. < 6.0% Corg.) soil materials. Conclusion The analysed soil materials had the Munsell value differentiated enough to enable their identification. The V/Ch quotient can help to trace the origin of postmurshic soils. Its narrow value (1–2) indicates that the postmurshic soil developed through advanced transformation of murshic soil materials, whereas a broader value (2–5) indicates that the postmurshic soil originated from dewatered Gleysols.

Pedodiversity and Organic Matter Dynamics in the North Apennines (Italy): Relationships among Soil Types, Biodiversity, and Ecological Functionality

“…Specifically, the BAC6 soil profile was located on the ridge, which allowed the deepening of the soil [56,57]. Considering the soil profiles as a whole, a darker soil color observed within the upper 18 cm for the HLD and HD soils than TD [54] indicated an overall higher organic matter accumulation in HLD and HD compared to TD [58,59]. This fact might be attributed to the slightly lower plant biomass amount in the forests of TD than in those of HD and HLD due to the diverse beech forest management, which affects the organic matter input into the soils [60,61].…”

Application of portable colorimeter for identification of mollic horizon and mollic-based soil groups

“…Soil colours have been applied to recognize soil composition and quality, and as one of basic parameters for soil classification since the beginning of the modern soil sciences (Linné, 1748). In particular soil colour may apparently reflect the origin and content of organic matter in soil (Łabaz et al, 2019;Łachacz and Załuski, 2023;Zhang and Hartemink, 2019), transformation/degradation of soil humus and humus horizons (Drewnik and Żyła, 2019;Łabaz and Kabała, 2016), mineral weathering and accumulation of iron compounds (Barajas and Ceron, 2022;Jankowski and Bednarek, 2022;Wakwoya et al, 2023), pedogenic accumulation of secondary carbonates and gypsum (Ayala-Nińo et al, 2022), illuvial accumulation of humus, iron, and clay (Durn et al, 2023;Gus-Stolarczy et al, 2023), water stagnation and redox processes (Repe and Pristovsek, 2022;Świtoniak et al, 2022), morphological transformation of soil profile (Czigány et al, 2020;Krupski et al, 2017;Mendyk et al, 2020;Świtoniak, 2014), persistence of parent materials in soil, in particular the light-coloured limestones/dolomites (Łabaz et al, 2022), lithogenic stratification of soil profile from alluvial (Jonczak et al, 2023;Kawałko et al, 2021;Loaiza-Usuga et al, 2022) or glacial (Kabala et al, 2022;Woronko et al, 2022) sedimentation, and other.…”