Ray Weil was a guest speaker at the 2017 National No-Tillage Conference in St. Louis. His presentation focused on how cover crops benefit soil nutrient levels not only in topsoils, but in lower depths as well.
Ray is a Univ. of Maryland professor and co-author of Nature and Properties of Soil.
Here’s a link to the podcast he delivered this year.
Ray’s research has covered how cover crops influence soil nutrient profiles at various depths and optimal planting dates for cover crops, their effects on moisture retention and how compaction influences deep root penetration.