Conventional practice of applying fertilizer and irrigation are empirical, often resulting in negative consequences to the environment and human welfare due to the insufficient or excess usage of fertilizer and water. Hence there is a persistent need for the knowledge to assist farmers in determining the quantity and timing of fertilizer and water application to maximize crop yield, minimize waste, and reduce cost. In this study, we aim to develop a highly sensitive radio frequency microfluidic coplanar waveguide array (MCWA) based sensor that can measure N-containing species down to the 3 picomolar by detecting small changes in permittivity of the sample solution upon analyte binding. Based on the single senor unit, we will develop an integrated MCWA sensor array by constructing a series of electrical and microfluidic circuits with each of the sensor units targeting specific analyte species for simultaneous measurement of different N-containing species simultaneously. The MCWA sensor array will be further integrated into a field-deployable soil probe and used to demonstrate the ability of mapping nitrate, ammonium, pH and soil moisture content on the farm using a network of sensor probes spread over a large area. The data from the sensor networks can be used to determine when and how much fertilizer and water should be applied, enabling just-in-time and just-enough geospatial applications of fertilizer and irrigation water, which would contribute to the food-energy-water nexus by increasing crop yield and, at the same time, reducing usage of water and fertilizer.