The video was a very good review and did seem to advocate (pure?) cow manure as a perfect soil. It was a very interesting idea to dry the manure fresh, then only crumble it a little. I wonder if that was their "secret" for reducing comapction.
(I don't recall them saying either "add lots of this to existing soil", or "grow right in 100%
pure manure , without adding any mineral soil at all".
That surprises me: I would expect PURE manure to subside and compress, loosing its air spaces, then retain too much water, drain poorly and prevent sufficient aeration. Most soils would probably benefit greatly from adding enoguh composted manure to make it 20% to 70% of the soil, but it seems to me that the last 30% risks seriously decreasing drainage and aeration.
(Of course, that's only a concern if your soil leans in the "clay and silt" direction instead of the "sandy" direction.)
It especially surprised me that their "perfect soil" worked well in a small pot. Small containers are where I would think that aeration and drainage were most important. Maybe dry manure nuggets in small pots need a few weeks or months of softening before they subside and compress their air spaces out of existence.
Maybe the trick is to crumble it slightly while very dry, and then compress it slightly in the bed or in the field. That might make the manure crumbs or clods stable enough that air channels survive rain and compression. Or maybe the people making this video don't have much rain and don't need excellent drainage. Or maybe they have sandy, gravelly soil. And maybe they don't run tractors back and forth over their fields so their soil doesn't need to resist compaction.
Also, did that video say much about weed seeds? Maybe it is less of a problem if your cows graze only on your own fields, so that your manure only has weed seeds from weeds that are already common in your fields.
This paper makes the point that 60% of some weed seed varieties survive passing all the way through a cow. They need seven days at 130 F, or 30 days at 145 degrees F, or even more heat or time, to be killed during composting.
http://www.animalagteam.msu.ed...
P.S. My comments about weed seeds are 100% "do as I say, don't do as I do". I let live weed seeds get into my compost heap last year and saw dense, lush monocrops of weeds take over every bed like the Red Army descending on Hungary.
If I had had access to enough manure that the center of my piles got HOT, I might have squeaked through letting weed seedheads into the pile.
