A field test of an electrical-capacitance method for measuring soil-water content

Several studies have compared gravimetric sampling to the neutron-attenuation method of soil-water measurement. However, less is known of the relationship between these two methods and a more recently developed technique based on electrical capacitance. Our field experiment allowed us to: (1) determine the accuracy of the neutron-moderation and electrical-capacitance methods by comparison to gravimetric sampling; (2) establish a relationship between the three methods; and (3) determine the field effectiveness, applicability, and ease of operation of the methods. The principal hypotheses are that we can establish the relationship between the three methods using simple regression, and that the three methods give statistically equivalent measures of soil-water content and thus can be used interchangeably. An alternative hypothesis is that no valid relationship exists between the three methods, with each giving a statistically different measure of soil-water content. We found that the electrical-capacitance method provides a viable alternative to the neutron-attenuation method of soil-water measurement in the field.