Evaluation of cesium-137 conversion models and parameter sensitivity for erosion estimation.

Area of Science:

• Environmental Science
• Soil Science
• Geomorphology

Background:

• The Cesium-137 (Cs) technique has been a primary method for soil redistribution estimation since the 1970s.
• Existing Cs-conversion models often lack theoretical validation and empirical testing.
• Accurate soil erosion and deposition quantification is crucial for land management and environmental studies.

Purpose of the Study:

• To validate four widely used Cs-conversion models for soil redistribution.
• To analyze the sensitivity of model parameters to estimate water erosion.
• To assess the efficacy of ordinary kriging in enhancing soil redistribution estimations.

Main Methods:

• Soil samples were collected on a 10-m grid from a 1.6-ha plot with measured soil loss data since 1978.
• Four Cs-conversion models (Proportional Model, Simplified Mass Balance, MBM2, MBM3) were applied to estimate soil redistribution.
• Ordinary kriging was employed to interpolate soil redistribution rates and assess improvements.

Main Results:

• Reference inventory significantly impacted water erosion estimates, followed by particle size correction and tillage depth.
• The Proportional Model (PM) showed lower relative errors (28% without, -17% with kriging) compared to mass balance models.
• Kriging interpolation generally improved the accuracy of mean soil redistribution estimates across models.

Conclusions:

• The Proportional Model demonstrated superior performance over mass balance models under the studied conventional tillage conditions.
• Ordinary kriging is a valuable tool for improving the accuracy of spatial soil redistribution estimates.
• Further research is needed to evaluate advanced mass balance models (MBM2, MBM3) in scenarios with significant loss of recently deposited Cs.