Field calibrations of a Diviner 2000 capacitive soil water content probe on a shallow groundwater site and the application in a weighable groundwater lysimeter

Ottfried Dietrich and Jörg Steidl

Agricultural Water Management, 2021, vol. 252, issue C

Abstract: The determination of the volumetric soil water content θv by means of capacitive profile probes is often applied to investigate the soil water storage change ΔS that serves as basis for decisions in agricultural water management. The soil properties have a big effect on the accuracy of the θv measurements. The use of only one calibration function, often provided by the manufacturers of the probes, cannot fulfil the requirements of all site conditions. Therefore, many individual calibration functions have in the past been determined for different soils and sensors. A literature review of existing calibration functions of the capacitive profile probe Diviner 2000 shows the broad range of available functions. The review makes it clear that there is a lack of functions for organic soils. These soils are typical soils of wet sites with shallow groundwater tables. The soil moisture is of big importance for many ecological processes of these sites and therefore an exact determination of θv is important. A Diviner 2000 profile probe was calibrated on such a shallow groundwater site in a classic field calibration procedure and the determined functions were applied to the soil profile of a weighable groundwater lysimeter. The soil water storage change ΔS was estimated with the measured θv values and compared with the measured mass change Δm of the lysimeter. The mean error (bias) between ΔS with the field calibration function and Δm was 7.8 kg and the root mean squared error (RMSE) 19.9 kg. An iterative adaptation of the calibration functions to the measured Δm values of the lysimeter reduced the bias to 0.9 kg and the RMSE to 14.0 kg. The investigations illustrate the problems of a classic field calibration under the conditions of a shallow groundwater site with low θv changes in deeper soil horizons and soils with high Corg contents as well as the inaccuracy in the determination of ΔS based on θv measurements with capacitive profile probes.

Keywords: Shallow groundwater site; Organic soils; Volumetric soil water content; Capacitance probe; Diviner 2000; Field calibration; Lysimeter; Water storage change (search for similar items in EconPapers)
Date: 2021
References: View references in EconPapers View complete reference list from CitEc
Citations:

Downloads: (external link)
http://www.sciencedirect.com/science/article/pii/S0378377421001396
Full text for ScienceDirect subscribers only

Related works:
This item may be available elsewhere in EconPapers: Search for items with the same title.

Export reference: BibTeX RIS (EndNote, ProCite, RefMan) HTML/Text

Persistent link: https://EconPapers.repec.org/RePEc:eee:agiwat:v:252:y:2021:i:c:s0378377421001396

DOI: 10.1016/j.agwat.2021.106874

Access Statistics for this article

Agricultural Water Management is currently edited by B.E. Clothier, W. Dierickx, J. Oster and D. Wichelns

More articles in Agricultural Water Management from Elsevier
Bibliographic data for series maintained by Catherine Liu ().