The potential of gamma-ray spectrometry as supplementary information for mapping central European soils Ulrich Schuler & Michael Bock, Rainer Baritz, Jan Willer, Enrico Pickert, Kati Kardel, Ludger Herrmann

Detailed and continuously updated soil information is required: to determine protection zones where erosion is noticeable to determine intervention zones where land use intensification seems to be wise to optimize consumption of fertilizer and irrigation water for flood prediction Why gamma-spectrometry?  the necessity to exploit remote and fast non-destructive proximal sensing

Soil mapping: Cook et al 1996, Bierwirth 1997, Wilfrd & Minty 2007 Erosion: Dickson et al 1996 Land use and land degradation: Gunn et al 1997 Salinity: Anderson-Mayes 1997, Dent 2007 Texture: Pracilio et al 2006 Soil porosity, density: Beckett 2007 The most significant misunderstanding surrounding the application of radiometric surveying for soil mapping is the fact that not all characteristics that are diagnostic of a soil type are reflected in radiometric data, and not all the characteristics of the radiometric data represent changes in soil type (Beckett 2007). Gamma spectrometric applications for soils

Concepts behind soil type mapping application B Limestone t Residual accum. A Loess t Translocation Bg Fluvial sediment t Absolute accum. E Bt A A Th U K K Bt E

HWSD, FAO / IIASA / ISRIC / ISSCAS /JRC, (2012). General Soil Map of Thailand 1:1M, Vijarnsorn and Jongpakdee, (1979). The national soil map is coarse, does not contain further information about soil properties, and is geo- metrically (the borders of units) outdated. Example: Status of available soil information in Thailand

Gini index confirms importance of gamma spectrometric data for map unit prediction. K and Th radiation allow for separation of reference soil groups (Schuler et al., 2011). Example: Soil mapping in Thailand

1550 Acrisol K = 0.7 % Limestone 1494 Acrisol K = 1.1 % Granite/gneiss No depth trends for Acrisols Radio K depth functions of RSGs in Thailand Clear depth trends for high activity RSGs 1625 Alisol Mudstone K = 2.6 % 1678 Luvisol Siltstone K = 2.6 %

K-depth functions explanation No mono-variate explanation by texture! Explanation by clay * BD * CEC clay

Th-radiation Case study - Chemnitz eTh [ppm] Geology Soil Th-radiation

Radiometric signatures of Leptosols, Cambisols and Podzols Case study - Chemnitz

Soil texture prediction using gamma spectrometery Case study - Chemnitz

Dose rate [nGy h-1] Radiometric signatures of different parent rocks Case study - Ehingen gravel limestone landfill limestone marlstone freshwater limestone, marly freshwater limestone loam

Case study - Ehingen Kolluvisol Parabraunerde-Terra fusca; Pelosol Parabraunerde,Terra fusca, Pseudogley Kalkgley Lockersyrosem Pelosol Humus-Pelosol Rendzina Pararendzina-Pelosol Braunerde-Pararendzina Pararendzina Radiometric signatures of different soil types Dose rate [nGy h-1]

Conclusions is useful to distinguish certain soil types along geochemical gradients distinguish soil properties (e.g. texture) as well as characteristics (e.g. potential rooting volume) is most often linked to a combination of soil properties (e.g. carbonate concentration and water saturation) requires parent material information Gamma spectrometry

Outlook investigation of the radiometric signal along different landform gradients, e.g. salt concentration, texture, moisture investigation of alternative channels in the gamma ray spectrum (0-3 MeV) investigate the effect of increasing loess coverage

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