A Simple Alternative Instrument for Measuring Temporal Soil Water Content in Repacked Soils

Hermawan, Bandi and Agustian, Indra and Suhartoyo, Hery and Sukisno, Sukisno (2017) A Simple Alternative Instrument for Measuring Temporal Soil Water Content in Repacked Soils. In: The Second International Symposium on Sustainable Agriculture and Agro-Industry (ISSAA 2017), 28-29 March 2017, Walailak University, Thailand. (Unpublished)

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Abstract

Information on temporal soil water content is needed under soil and water management practices such as irrigation scheduling, but the available instruments are either difficult to use or expensive. The objective of the study is to develop a dielectrically-based instrument to measure temporal soil water content. Electrical impedance, Z, representing the dielectrical variable, was measured from March to August 2016 using an auto-balancing bridge circuit functioned as a voltage sensor using two inverting amplifiers. The input voltage was resulted from sinusoidal voltage generator at a frequency of 3 kHz. When inserted into the soil, resulting voltage was analyzed in a microcontroller to determine Z of the measured soil. A hundred of repacked soils were used in this study, the samples were saturated for about 24 hours, Z values (in kΩ) were measured using the instrument. At the same time, soil water content values (θg in g.g-1) were determined using a standard gravimetric method. Soil samples were allowed to evaporate, both Z and θg measurements were repeated every second days. Pairs of Z and θg values were regressed to find the best equation in calculating water content from the measured impedance. Results showed that temporal soil water content were best calculated from Z values using a non-linear regression of θg = a.Zb where a and b were constants. About 90 percent of study soils had R2 values of above 0.90, suggesting the accuracy of the proposed instrument. These findings would contribute to the improvement of water use efficiency in crop production. Keywords: electrical impedance, instrument, repacked soils, soil water

Item Type: Conference or Workshop Item (Poster)
Subjects: S Agriculture > S Agriculture (General)
Divisions: Faculty of Agriculture > Department of Soil Science
Depositing User: Mr. Bandi Hermawan
Date Deposited: 02 Jun 2020 09:52
Last Modified: 02 Jun 2020 09:52
URI: http://repository.unib.ac.id/id/eprint/21184

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