Recent Advances in the Cosmic-Ray Neutron Probe Method: Estimating Soil Water Content across Spatiotemporal Scales.

Local, state, national, and global initiatives exist on collecting and maintaining long-term soil water content observation networks. However continual funding for such networks is challenging for a variety of factors, in particular quantifying the societal value of their existence. Fundamentally this is because soil water content is a highly heterogeneous state variable where society values medium to large-scale water fluxes (i.e. evapotranspiration of crops, recharge into aquifers, runoff into streams). In this work I will summarize the value of soil water content observations in understanding the dynamical system, highlighting recent advances in the stationary and roving cosmic-ray neutron probe method for estimating soil water content and parameters that control water flux. Specific examples from a variety of agricultural applications in the Midwestern United States will be presented.