Ion-Selective Electrode Offers Accurate, Inexpensive Method for Analyzing Soil Solution Nitrate in Remote Regions

Abstract

Nitrogen (N) applied as fertilizer is subject to runoff and leaching. Nitrate (NO3−-N) concentrations in soil solution reflect the impacts of farm management on N cycling. Some of the most remote regions in the world are undergoing rapid land-use change, yet there are major barriers to conducting research in these locations. Fortunately, new tools such as ion-selective electrodes (ISEs) provide low-cost and simple methods for conducting chemical analysis in the field. Researchers compared soil solution NO3−-N concentrations measured using an ISE with concentrations measured on a colorimeter (cadmium reduction) and found good agreement (r2 = 0.96, P < 0.0001) between the two methods. The ISE is also 66 times less expensive than in-country laboratory analysis or shipping and analyzing the samples in the United States. Thus, the ISE is an excellent tool for rapid analysis of N in soil solution, providing critical information on N dynamics in remote regions.