Response of reflectance to dielectric properties of bare tills

• Published in: International journal of remote sensing Vol. 25; no. 3; pp. 627 - 641
• Main Authors: Middleton, M., Teirilä, A., Sutinen, R.
• Format: Journal Article
• Language: English
• Published: Taylor & Francis Group 01.02.2004
• ISSN: 0143-1161; 1366-5901
• DOI: 10.1080/0143116031000139953

Parent tills are routinely exposed as a result of mechanical sitepreparation during post-harvest forest regeneration in northern Fennoscandia. Scots pine (Pinus sylvestris L.), the species most often chosen for artificial reforestation, only thrives on sites with low soil moisture content (θ v ). Hence objective methods are needed to measure θ v of bare tills to provide information on suitability of a site for pine. We studied the relationship between the spectral reflectance (350-2500 nm) and dielectric permittivity (ϵ, as dependent on the soil θ v ) of tills varying in clay fraction content (2.4-5.5%), fine fraction content (23.5-47.1%) and organic matter content (OMC, 0.6-5.8%). Laboratory measured data, analysed with correlation and regression analysis and mixed effect modelling, showed a significant negative correlation between reflectance (500-2500 nm) and the soil ϵ (i.e. soil θ v ). In addition, the proposed generic exponential models (y=ae bx +c) explained the reflectance-soil ϵ relationship well (adjusted goodness of fit 0.8-0.85) for tills with low OMC (<1.7%). The results suggest that high-resolution remotely sensed data can provide an effective alternative to traditional soil surveys for recognition of soil θ v patterns on clear-cut mechanically prepared sites.