Proximal sensing of soil moisture

Soil moisture (SM) is of paramount importance for society and the global environment. Accurate SM information is at the core of a plethora of applications that include forecasting of weather and climate variability, projection and monitoring of drought conditions, precise agricultural irrigation management, conservation of water resources, monitoring of ecosystem response to climate change, and impact mitigation of natural disasters such as wildfires, landslides, floods, or dust storms, whose occurrence is intimately connected to the moisture status of the land surface. Variations in SM can have substantial impacts on ecosystem health, agricultural productivity, and forestry. In this chapter we present state-of-the-art and novel technologies and sensors for proximal sensing of SM together with the underlying concepts and theories.