Combining cosmic-ray neutron sensor and fallout ¹³⁷Cs to explore the connection of soil water content with soil redistribution in an agroforestry hillslope

Authors

Leticia Gaspar, Estación Experimental de Aula Dei
Trenton E. Franz, University of Nebraska-LincolnFollow
Arturo Catalá, Estación Experimental de Aula Dei
Iván Lizaga, Ghent University
María Concepción Ramos, Physics and Environmental and Soil Sciences-University of Lleida-Agrotecnio CERCA Center
Ana Navas, Estación Experimental de Aula Dei

Date of this Version

6-17-2023

Citation

Environmental Research 233 (2023) 116451. https://doi.org/10.1016/j.envres.2023.116451

Comments

Open access.

Abstract

To ensure sustainable agricultural management, there is a need not only to quantify soil erosion rates but also to obtain information on the status of soil water content and soil loss under different soil types and land uses. A clear understanding of the temporal dynamics and the soil moisture spatial variability (SMSV) will help to control soil degradation by hydrological processes. This study represents the first attempt connecting cosmic-ray neutron sensors (CRNS) with soil erosion research, a novel approach to explore the complex relationships between soil water content (SWC) and soil redistribution processes using two of the most powerful nuclear techniques, CRNS and fallout ¹³⁷Cs.

Our preliminary results indicate that CRNS captured soil moisture dynamics along the study toposequence and demonstrated the sensitivity of neutron sensors to investigate the effect of parent material on soil water content. The Empirical Orthogonal Function (EOF) analysis of the comprehensive data from seven CRNS surveys revealed that one dominant spatial structure (EOF1) explains 89.2% of SMSV. The soil redistribution rates estimated with ¹³⁷Cs at the nine locations along the hillslope, together with local factors related to soil properties (SOC, soil depth, hydraulic conductivity) and land use showed significant correlations with EOF. This study provides strong field evidence that soil type significantly affect SMSV, highlighting the key impact on soil erosion and sedimentation rates. Nevertheless, more research is needed to investigate the specific contributions of soil properties to the spatial variability of soil moisture and their subsequent effects on soil redistribution dynamics of interest for soil management.