Galvanic Cell Type Sensor for Soil Moisture Analysis

Abstract

Here we report the first potentiometric sensor for soil moisture analysis by bringing in the concept of Galvanic cells wherein the redox energies of Al and conducting polyaniline are exploited to design a battery type sensor. The sensor consists of only simple architectural components, and as such they are inexpensive and lightweight, making it suitable for on-site analysis. The sensing mechanism is proved to be identical to a battery type discharge reaction wherein polyaniline redox energy changes from the conducting to the nonconducting state with a resulting voltage shift in the presence of soil moisture. Unlike the state of the art soil moisture sensors, a signal derived from the proposed moisture sensor is probe size independent, as it is potentiometric in nature and, hence, can be fabricated in any shape or size and can provide a consistent output signal under the strong aberration conditions often encountered in soil moisture analysis. The sensor is regenerable by treating with 1 M HCl and can be used for multiple analysis with little read out hysteresis. Further, a portable sensor is fabricated which can provide warning signals to the end user when the moisture levels in the soil go below critically low levels, thereby functioning as a smart device. As the sensor is inexpensive, portable, and potentiometric, it opens up avenues for developing effective and energy efficient irrigation strategies, understanding the heat and water transfer at the atmosphere-land interface, understanding soil mechanics, forecasting the risk of natural calamities, and so on.

Redox Active Binary Logic Gate Circuit for Homeland Security

“…UV–vis spectroscopy of as synthesized polymer indicates the signature peaks at longer wavelengths corresponding to its conducting states (Figure S6, Supporting Information). − When the Al electrode is short circuited to polymeric cathode half-cells, the polaronic band at longer wavelength is blue-shifted for PPy (483 to 465 nm), PANI (836 to 609 nm), and PEDOT (686 to 612 nm) electrodes, spectroelectrochemistry data, (Figure S6, Supporting Information) indicating the formation of the nonconducting state of respective polymers. After 1000 s of the removal of short circuiting, the recorded spectra of conducting polymers demonstrate their recovery almost to respective conducting states.…”

Precision Fertilization and Irrigation: Progress and Applications

“…Examples of soil information management, crop growth information, pest and weed information, and farmland environmental information acquisition are listed in Table 2 [49][50][51][52][53][54][55][56][57][58][59][60][61][62][63][64][65][66]. The methods and techniques used are analyzed, and the data obtained and the development of precision fertilization and irrigation are briefly summarized.…”

Precision Agriculture for Crop and Livestock Farming—Brief Review

“…Soil moisture content sensors (or “volumetric water content sensors”) such as tensiometers evaluate the soil water tension or suction, which is a denotation of the plant root system effort while extracting water from the soil. It can be used to estimate the amount of stored water in the soil or how much irrigation is required to reach a desired amount of water in the soil [ 13 ]. Soil moisture content can also be determined by Photodiode, an optical sensor that uses the light to measure soil properties, namely clay, organic matter, and moisture content of the soil [ 9 ].…”