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:

  • 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

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.