In situ soil moisture sensors in undisturbed soils

Authors: CALDWELL, T. - Us Geological Survey (USGS); Cosh, Michael; Evett, Steven - Steve; EDWARDS, N. - South Dakota State University; HOFMAN, H. - Natural Resources Conservation Service (NRCS, USDA); ILLSTON, B.G. - University Of Oklahoma; MEYERS, T. - National Oceanic & Atmospheric Administration (NOAA); SKUMANICH, M. - Collaborator; SUTCLIFFE, K. - Natural Resources Conservation Service (NRCS, USDA)

Submitted to: Journal of Visualized Experiments
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/18/2022
Publication Date: 11/18/2022
Citation: Caldwell, T., Cosh, M.H., Evett, S.R., Edwards, N., Hofman, H., Illston, B., Meyers, T., Skumanich, M., Sutcliffe, K. 2022. In situ soil moisture sensors in undisturbed soils. Journal of Visualized Experiments. https://doi.org/10.3791/64498.
DOI: https://doi.org/10.3791/64498

Interpretive Summary: Soil moisture monitoring has been growing in popularity around the world, with many advances in technology. The goal is for each of these technologies to be referenced to a true value and produce an accurate and representative estimate of soil moisture at the monitored location. The first step toward this goal is to establish a procedure for installation of the sensors as well as guidance on repair and maintenance. This document provides both written and visual procedures for soil moisture sensor installation which will be of value to field scientists around the world who can now observe actual installations of sensors.

Technical Abstract: Soil moisture directly affects the climate system, food security, and ecosystem services. However, the adoption of soil moisture data into operations has been slow due to inconsistent data collection, the small support scale of in situ sensors, and its inherent variability both in space and time. Soil moisture, or more quantitatively volumetric soil water content (SWC), is measured at the site-scale using buried, in situ sensors that infer SWC from an electromagnetic response. This signal can vary considerably with site conditions like clay content and mineralogy, soil salinity or bulk electrical conductivity, and soil temperature; each of which can have varying impacts depending on the sensor technology. Furthermore, poor soil contact and sensor degradation can affect the quality of these readings over time. Unlike more traditional environmental sensors, there are no accepted standards for SWC sensors, maintenance practice, or quality control for these data records. As such, SWC is one of the most challenging variables in an environmental monitoring network. Here, we attempt to establish a Community of Practice on the installation and maintenance of these sensors so that future research and applications have consistent guidance on site selection, sensor installation, data interpretation, and long-term maintenance of SWC monitoring stations. The videography focuses on a multi-agency best-practices and recommendations for the installation of in situ SWC sensors. This documentation presents an overview of this protocol along with the various steps required for high-quality and long-term SWC data collection. This protocol will be of use to scientists and engineers hoping to deploy a monitoring station or an entire network