Development of Electronic Nose (E-Nose) Sensors for the Detection and Monitoring of Water Deficit in Agricultural Crops

• Grant number: 25/26204-9
• Support Opportunities: Scholarships in Brazil - Post-Doctoral
• Start date: May 01, 2026
• End date: April 30, 2029
• Field of knowledge: Engineering - Materials and Metallurgical Engineering - Nonmetallic Materials
• Principal Investigator: Daniel Souza Corrêa
• Grantee: Rafael Aparecido da Silva
• Host Institution: Embrapa Instrumentação Agropecuária. Empresa Brasileira de Pesquisa Agropecuária (EMBRAPA). São Carlos , SP, Brazil

Abstract

Water deficit is one of the main factors responsible for reducing agricultural productivity, causing significant losses in regions affected by climate change and shortages of water resources. Early detection of this process is a strategic tool to ensure sustainability and efficient water use in agricultural systems. The development of electronic nose (e-nose) systems has emerged as a promising approach, as it enables the detection of volatile organic compounds (VOCs) emitted by plants undergoing water stress, resulting from metabolic alterations, even before visual symptoms appear. Thus, the objective of this research project is to develop and validate an electronic nose system capable of identifying and classifying different levels of water stress in agricultural crops. To achieve this, sensor materials will be synthesized and characterized in terms of crystal structure, morphology, composition, and electrical properties. A sampling chamber will be designed and constructed using acrylic or PTFE, with precise control of temperature, humidity, and gas flow ensured by auxiliary sensors integrated into a microcontroller. The electronic data acquisition system will consist of a multiplexer module coupled to a potentiostat/galvanostat equipped with an electrochemical impedance spectroscopy (EIS) module. The data processing code will be developed in Python, including routines for acquisition, filtering, visualization, and multivariate analysis (PCA and HCA). The system will be tested on soybean, maize, or wheat plants grown in pots and subjected to three different water regimes: full irrigation, moderate deficit, and severe deficit. During the experiments, the e-nose system will continuously collect the air surrounding the plants, correlating the measured signals with VOC emission profiles and physiological parameters. The collected data will be processed and analyzed to identify characteristic patterns associated with each level of water stress and to validate the sensitivity and reproducibility of the developed system. (AU)