Engineers at the University of Wisconsin-Madison have developed groundbreaking low-cost sensors capable of continuously monitoring nitrate levels in common Wisconsin soil types. These printed electrochemical sensors promise to revolutionize nutrient management practices for farmers, offering real-time data that could lead to significant economic benefits.
Nitrate, essential for crop growth, poses environmental and health risks when excessive amounts leach into groundwater. The newly developed sensors not only enable precise monitoring of nitrate levels but also serve as a tool for agricultural research, facilitating the study of nitrate leaching and the development of effective mitigation strategies.
Traditionally, methods for monitoring soil nitrate are labor-intensive, expensive, and lack real-time capabilities. Recognizing these limitations, Professor Andrew and his team leveraged inkjet printing technology to fabricate potentiometric sensors. While potentiometric sensors are adept at measuring nitrate in liquid solutions, their application in soil is challenging due to abrasive soil particles that interfere with accuracy.
To address this challenge, the researchers devised a solution using polyvinylidene fluoride, a material featuring ultrafine pores that selectively allow nitrate ions to pass through while blocking soil particles. Moreover, its hydrophilic nature ensures water absorption, crucial for stable sensor performance in soil environments.
The team’s breakthrough was published in a March 2024 issue of Advanced Material Technologies, detailing successful sensor trials in Wisconsin’s sandy and silt loam soils. These trials confirmed the sensors’ accuracy and robustness in diverse soil conditions.
Moving forward, the researchers are integrating their nitrate sensors into a multifunctional “sensing sticker,” incorporating moisture and temperature sensors on a flexible plastic surface. This sticker, equipped with adhesive backing, allows for easy deployment at various depths in soil using rods, facilitating comprehensive soil monitoring.
In summer 2024, the team plans extensive field testing at UW-Madison’s Hancock and Arlington Agricultural Research Stations, deploying 30 sensing rods to validate sensor performance across different agricultural scenarios.
The engineers are also pursuing patent protection for their technology through the Wisconsin Alumni Research Foundation, ensuring their innovative sensors can benefit agricultural practices beyond Wisconsin.
This pioneering development promises not only to enhance agricultural productivity through optimized nutrient management but also to safeguard groundwater quality and environmental sustainability, marking a significant advancement in precision agriculture.