Decoding Nitrogen Dynamics in Soil through Novel Integration of in-situ Wireless Soil Sensors with Numerical Modeling

Excess nitrogen leaching from agricultural and horticultural lands into waterways is a long-standing
challenge for agricultural sustainability and environmental protection. An effective approach to improving
the water/fertilizer use efficiency is through precision farming practices guided by real-time monitoring
and near-term forecast of crop irrigation and fertilization needs. However, this initiative is hampered by
the lack of reliable sensing technologies and modeling tools for elucidating the spatiotemporal variability
of soil moisture and nitrogen concentration. The current state of the art is to collect soil samples at field
sites and bring to the laboratory for analysis, which is prohibitively expensive, labor-intensive, and is
unable to track the transient variation of soil nitrogen content in a timely manner.

This interdisciplinary collaborative US-UK SitS project aims to tackle the grand challenge of decoding
nitrogen dynamics in the soil through seamless integration of four innovative solutions: hydrogel-coating
solid-state ion-selective membrane (HS-ISM) based wireless nitrogen sensing technology, droplet-flow
microfluidic-based sensors (DFMS) as in situ calibration, high-resolution profiling of nitrogen species
and moisture level in different ecosystems, and data-driven modeling of rhizosphere nitrogen dynamics.
Together, this project will transform existing labor-intensive and inefficient soil analysis practice to
automated and highly efficient soil nitrogen dynamics decoding and field modeling strategy, and thus
advancing the underlying science and engineering of soil nitrogen dynamics and providing guidance for
sustainable agricultural and ecosystem management.

This US-UK SitS project features many scientific and engineering innovations that will yield high payoff for a fundamental understanding of soil nitrogen dynamics, providing a brand new vision in nitrogen
sensing technology and soil modeling methodology, and enabling better management of natural resources and agricultural practices in both US and UK. "Visualizing" the soil moisture and nutrient conditions
using our cutting-edge in-situ sensing technology and data-driven modeling approach will, for the first time, execute swift and precise agricultural practices, thus leading to high efficiency and resilience.
Multiple broader impact initiatives including hands-on experiments, freshman workshops and seminars will stimulate students' interest and passion in learning and in STEM career, especially for
underrepresented groups. All these features contribute to improving resource use, increasing food security, and reducing contamination of soil and water in US and UK, and thus help addressing the
National Academy of Engineering Initiative of "Grand Challenge of Managing the Nitrogen Cycle".