It sound like a plausible fusion but the problem that jumps out is with attempting to infiltrate more on the ridge. Depending on the soil type it would seem the best way to soak in more where it's needed, but it doesn't address blowout's in the uncompacted swale wall during event rainfalls. You only have to have 1 in a year to domino all the swale walls downhill in the same place. A much more practical approach would be to put event rainfall compacted spillways on the swale when the water reaches a peak holding capacity at the ridges, staying on contour has to do more with the greater purpose of filling dams. If your in a situation where you have high drainage soils then his approach wouldn't be as dangerous in producing a swale wall breach.
Swales are a tree growing system, I think keyline is a better pasture system.
The two don't fight, they just occupy different niches.
This also gets down to a level of distinction and discernment that would be so much better examined through long-term documentation and monitoring, which the Pc movement is more than a little deficient in. Hopefully in a decade's time we'll have some better data, or at least stories, to support the effectiveness of these different methods.
Well keyline plowing goes back to black and white photos, the wallace plow was the largest selling agricultural implement in Australia in the 80's. In regards to how much or how little they work well there's to many factors to make some sort of salesman's pitch about it, hillside vs valley swales on an on. I was mainly looking at what most permaculture enthusiast fail to be logical about, the downsides that can produce failure and swale blowout's is addressed in detail in the G.Lawton B.Mollison pdc, There's allot that if you overlook something as simple as a cattle track above your swale is enough to blow out the walls in a serious storm which nobody can say doesn't occur in their situation. If you want to wet up ridges a keyline rip line is just enough water, but I wouldn't send a 1 meter wide 12 inches deep swale full of water towards 1 singular point in a swale. Swales don't work if there not level they just become a drainage ditch, the best of both worlds seems to be more of the worst of both downsides. If only the landunderground was as uncomplicated as the academic presentation on how water will infiltrate soil.
10 Podcast Review of the book Just Enough by Azby Brown