I thought that consultants prided themselves on being up to date. The publication you posted ( in total, by the way ) was written in 1993 and it referenced 2 publications from 1977 and 1 from 1985. Didn’t see the words “preferential flow” even mentioned. Back then, no one thought to look for preferential flow nor did they understand that microbes in surface applied manure extend their biological viability by using organic acids/materials in manure to encapsulate themselves – and ultimately end up in the tile lines and the rivers they drain into. In 1993, every farm publication was running articles on how to count earthworm populations, how to seed soils with earthworms, etc. Do you suppose, just maybe, that there is a reason that the the ag press doesn’t run these anymore?