Field measurement of soil moisture using neutron probes

Abstract

Soil moisture measurements are critical to all field studies of soil-plant-water relationships. Dependable and reliable techniques are required to provide such measurements. Neutron probes were developed more than 40 years ago and continue to be used today. They offer many advantages as a measurement technique, the most important of which is non-destructive, repetitive measurements of soil moisture. Much research has been focused on overcoming the two major limitations of neutron probes: measuring near-surface soil moisture and a smoothing of moisture data at sharp moisture discontinuities in the soil. Various techniques have been devised to overcome the first limitation and the error associated with the second is acceptable by probe users The dramatic decline in the number of articles in the scientific literature related to neutron probes during the past decade is likely an indication that neutron probe technology has matured and that neutron probes have become accepted as a reliable and dependable field technique for soil moisture measurement. Key words: Neutron probe, soil moisture, water budget