Carleton Bern of the US Geological Survey was the lead author on a two-part paper covering 1) water and solute movement and 2) geochemistry beneath BeneTerra’s longest operating deep subsurface drip irrigation system. The articles appear in the February 2013 issue of Agricultural Water Management. These can be accessed at Science Direct or by email request to BeneTerra.
http://www.sciencedirect.com/
installing deep drip irrigation tubing to 90 cm (36-in)