Measurement precision and accuracy of selected soil moisture sensors in response to changing type and content of soil organic matter

Bc. Donatus Dziedzorm Dzissah

Master's thesis

Abstract:

Various soil moisture sensors are widely used for research and practical purposes. However their accuracy and precision can be affected either the sensors themselves, either by various soil conditions in which they are used. This study was conducted to 1) carry out the individual sensor calibration for comparison of selected soil moisture sensors in order to evaluate the sensor precision and various reading devices response; 2) evaluate the sensor accuracy affected by different amount and type of organic matter added to the soil. Sensors 5TE and EC-5 combined with ProCheck, EM50 datalogger and ECHOcheck reading devices were tested. Two organic matter sources; biochar and compost were applied to soil of original organic carbon content of 2.07% from Český Krumlov district in the South Bohemia region of the Czech Republic at two organic carbon levels of 4% and 8%. Soil was artificially repacked into containers for uniform distribution considering the average dry bulk density of the soil originally determined in the field and measurements were taken after that using the various sensors and reading devices followed by gravimetric method of water content determination. This was repeated for series of moisture levels of 0% to 30% in intervals of 5% for each organic matter treatment where these organic materials were thoroughly mixed with the soil at ratios to obtain the desired organic matter level. Statistics showed significant differences among the individual sensors on one hand, and strong correlations between various organic matter levels and sensor outputs on the other hand, with accuracy of factory calibrations ranging between 3.1% and 7.1% which was improved by own calibration between 0.5 and 1% revealing the effects of changing types of organic matter content on the measurement precision and accuracy of soil moisture sensors.

Keywords

soil water content, 5TE, factory calibration, soil organic matter

Language used: English

Date on which the thesis was submitted / produced: 17. 4. 2019

Thesis defence

• Supervisor: Ing. Markéta Miháliková, Ph.D.

Czech University of Life Sciences Prague

Faculty of Agrobiology, Food and Natural Resources

Master programme / field:
Natural Resources and Environment / Natural Resources and Environment