Review of polymer-based sensors for agriculture-related applications

Abstract

Advancements in micro-electro-mechanical system (MEMS) and nano-electro-mechanical system (NEMS) technologies IntroductionIn agriculture, soil plays an important role in the overall yield of crop production. Although it is expected to enhance the yield by applying fertilizers, lack or excess levels of soil nutrients should be monitored. In general, for optimal control of soil conditions, it is necessary to measure nutrient content, moisture and pH levels, air humidity, temperature and composition of the soil at regular intervals. It is important to test the soil parameters to determine fertility, expected growth potential of the soil and measure nutrient deficiencies. 'pH' level is a measure of the acidity or basicity of the soil. Soil temperature influences crop growth since seeds, plant roots and microorganisms within the soil will not survive below some threshold temperature. Knowledge of soil humidity is important because it affects water-related reactions in the plants such as photosynthesis, pollination and even occurrence of plant diseases.1 Soil monitoring will also be useful for providing the basis for productions from soil such as food as well as controlling and regulating environmental interactions and sustaining biodiversity. Advancements in micro-electro-mechanical systems (MEMS) and nano-electro-mechanical systems (NEMS) as well as development of various chemical compounds has led to various methods and techniques for health monitoring and study of the soil. MEMS structures may be simple with no moving parts or be extremely complex with multiple moving elements under the control of integrated circuits. NEMS are next-generation MEMS devices, which are mainly in the nanometer scale. As a result, they are of low mass, high mechanical resonance frequencies, potentially large quantum mechanical effects such as zero-point motion, and a high surface-to-volume ratio that is useful for surface-based sensing mechanism.3 Figure 1 shows the structure of two commonly used MEMS structures: MEMS SU-8 polymer cantilever and MEMS microheater having suspended serpentine silicon beam as filament. 4,5 In this article, the authors present a review on reported polymers that are used for sensing various nutrients (which are also found in the soil) such as soil moisture, pH value and humidity. A polymer is

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Editorial

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