CV.98 Dataset
=============

Description
-----------
* Target Soil Properties: SOC, pH, Clay
* Groups of Features: vis-NIR 
* Sample size: 98
* Number of Features: 2,151
* Coordinates: Without coordinates because dataset was not georeferenced
* Location: Canton of Vaud, Switzerland
* Sampling Design: Stratified random sampling based on different treatments of organic amendments, fertilization, crop rotation and soil cultivation
* Study Area Size: 28 ha
* Geological Setting: Glacial or fluvioglacial deposits
* Previous Data Publication: Full dataset published in Metzger et al. (2024) but under embargo until June 2025
* Contact Information:
    * Konrad Metzger (konrad.metzger@agroscope.admin.ch), Agroscope
    * Luca Bragazza (luca.bragazza@agroscope.admin.ch), Agroscope
* License: CC BY-SA 4.0
* Publication/Modification Date (d/m/y): 28.02.25, version 1.0
* Changelog:
    * Version 1.0 (28.02.25): Initial release

Details
-------

Dataset
^^^^^^^
The dataset contains the following target soil properties and features:

Target Soil Properties:
""""""""""""""""""""""

SOC - Soil Organic Carbon
    * Code: ``SOC_target``
    * Unit: %
    * Protocol: Measured through titration after oxidization of the organic carbon (Walkley & Black 1934)
    * Sampling Date: May - June and September - October 2021
    * Sampling Depth: 0 - 20 cm

pH
    * Code: ``pH_target``
    * Unit: Unitless
    * Protocol: Measured in water suspension with a glass electrode with a 5:1 liquid:soil volumetric ratio (NF ISO 10390)
    * Sampling Date: May - June and September - October 2021
    * Sampling Depth: 0 - 20 cm

Clay
    * Code: ``Clay_target``
    * Unit: %
    * Protocol: Sieve-Pipette method, measured through fractioning the soil into the sand fractions by sieving, and the silt and clay fractions by sedimentation in water (Gee and Bauder 1986)
    * Sampling Date: May - June and September - October 2021
    * Sampling Depth: 0 - 20 cm

Groups of Features:
"""""""""""""""""

vis-NIR – Visible and Near Infrared Spectroscopy
    * Number of Features: 2,151
    * Code(s): ``wl_350``, ``wl_351``, ``wl_352`` ... ``wl_2500``
    * Unit: % (Reflectance)
    * Sensing: vis-NIR spectrometer (PSR+3500, Spectral Evolution, Haverhill, USA), in-situ from Edelman auger (denoted as scantype = a in original dataset publication), spectral range was 350 - 2500 nm at 3 - 8 nm intervals
    * Processing: Resampling to 1 nm intervals
    * Sampling Date: May - June and September - October 2021
    * Spectral Information (After Data Processing):
        * Data Representation: Wavelength (in nm)
        * Spectral Resolution: 1 nm
        * Spectral Range: 350 – 2500 nm

Examples
--------

.. code-block:: python

    from LimeSoDa import load_dataset, split_dataset
    from sklearn.linear_model import LinearRegression
    from sklearn.metrics import r2_score, mean_squared_error
    import numpy as np

    # Load and explore the dataset
    data = load_dataset("CV.98")
    dataset = data["Dataset"]
    folds = data["Folds"]
    coords = data["Coordinates"]  # Note: No coordinates available for this dataset

    # Split into train/test using fold 1
    X_train, X_test, y_train, y_test = split_dataset(
        data=data,
        fold=1,
        targets=["pH_target", "SOC_target", "Clay_target"]
    )

    # Fit model and get predictions
    model = LinearRegression()
    model.fit(X_train, y_train)
    predictions = model.predict(X_test)

    # Calculate performance metrics
    r2 = r2_score(y_test, predictions)
    rmse = np.sqrt(mean_squared_error(y_test, predictions))
    print(f"R-squared: {r2:.7f}")
    print(f"RMSE: {rmse:.7f}")

References
----------

Gee, G.W. & Bauder, J.W. (1986) Particle-Size Analysis. In: Klute, A., Ed., Methods of Soil Analysis, Part 1. Physical and Mineralogical Methods, Agronomy Monograph No. 9, 2nd Edition, American Society of Agronomy/Soil Science Society of America, Madison, WI, 383-411.

Metzger, K., Liebisch, F., Herrera, J. M., Guillaume, T., Walder, F. & Bragazza, L. (2024). Agroscope_SoilSpectralLibrary _2024. Zenodo repository. https://doi.org/10.5281/zenodo.11204174

Walkley, A. & Black, I. A. (1934). An examination of the Degtjareff method for determining soil organic matter, and a proposed modification of the chromic acid titration method. Soil science, 37(1), 29-38.