Provides functions for efficiently estimating properties of 
         the Van Genuchten-Mualem model for soil hydraulic parameters from 
         possibly sparse soil water retention and hydraulic conductivity data 
         by multi-response parameter estimation methods 
         (Stewart, W.E., Caracotsios, M. Soerensen, J.P. (1992) 
         "Parameter estimation from multi-response data" 
         <doi:10.1002/aic.690380502>). Parameter estimation is simplified 
         by exploiting the fact that residual and saturated water contents 
         and saturated conductivity are conditionally linear parameters 
         (Bates, D. M.  and Watts, D. G. (1988) 
         "Nonlinear Regression Analysis and Its Applications" 
         <doi:10.1002/9780470316757>). 
         Estimated parameters are optionally constrained by the evaporation
         characteristic length (Lehmann, P., Bickel, S., Wei, Z. and Or, D. (2020)
         "Physical Constraints for Improved Soil Hydraulic Parameter 
         Estimation by Pedotransfer Functions" <doi:10.1029/2019WR025963>) 
         to ensure that the estimated parameters are physically valid. 
         Common S3 methods and further utility functions allow to process, 
         explore and visualise estimation results.

Implements deterministic classification keys for the World
    Reference Base for Soil Resources 2022 (4th edition) and the Brazilian
    System of Soil Classification ('SiBCS', 5th edition). Provides a unified
    profile representation with explicit per-attribute provenance, multimodal
    extraction from field reports and photos via vision-language models,
    spatial priors from 'SoilGrids' and national soil maps, and gap-filling of
    soil attributes from Vis-NIR or MIR spectra via the Open Soil Spectral
    Library ('OSSL'). The taxonomic key itself is never delegated to a language
    model; LLMs are restricted to schema-validated extraction. Each
    classification result reports a key trace, a provenance-aware evidence
    grade, and ambiguities that further measurement would resolve.