Ditch-Witched hugelkulture swale

An idea i had the other day while using a ditch-witch to lay some conduit for a solar install...

a ditch witch trench digger is a marvelous tool. it can dig a 18" deep by 6" wide trench at a few feet per minute, and throws up a small berm to one side of the trench. so, i thought, why not run a ditch-witch on contour so that the spoil (small berm) is thrown up on the downhill side of the trench. the trench can then be filled with logs, sticks and rough mulch (the bottom 12") and covered with 6" of soil/compost/ammendment mix. the spoil is essentially well tilled, and could be seeded with clover, clump grasses, comfrey or whatever groundcover is appropriate. the trench, filled with organic matter, helps water infiltration and to capture nutrients otherwise washing away. My previous method of making small swales (2-3' width) was to use a small motorized tiller to break up the soil, usually takes 2-3 passes, and then form the swale with hoes and shovels - not too labor intensive, but still plenty work, and lots of fighting the machine. I'd imagine that two people working with a ditch-witch could form about 150ft/hour of trench (in not too rocky soil), and say another hour to backfill the trench with organic matter. so two people could make something like 600 feet of hugel-swale in a long, pretty frustrating days work. most of the swales ive been making are spaced at about 12 feet, due to high rainfall and pretty steep slopes...so 7,200 sq ft/day, say 5 days to finish off an acre. less if the swales can be spaced out more of course. a ditch witch could safely be used to a 25 degree slope, or less safely up to about 35 degrees...which is pretty steep for any machine running cross-slope.

i'm a fan of small machines to do precise work. i loath to let a backhoe or bulldozer tromp around my land - it's seen more than it's fair share of overweight, unweildy machines with dumb humans driving them already. SO, the next time i have free time (hah), am caught up on chores (never?), and need to plant more trees (always), i'm going to try this method. in the mean time...any comments?

the attached piece of art shows a side view of the slope, with the trench filled with branches/mulch, a cover crop planted on the spoil/berm, and a tap-rooted legume or other useful tree.

edit: thinking about it, two weeks work with two folks (one week forming swales, one week planting trees) would get an acre of orchard on steep-ish land planted...and the combination of hugel and swale should mean no irrigation and very little fertilizing, even in the first year. enough fertilizer (100% organic locally sourced, of course ) could be applied in the hugel-trench to last a long, long time, given the huge carbon buffer of rough mulch and logs. hundreds of linear feet of mycellium-connected trees growing on contour, restoring damaged soil...oh, it warms my heart to just think of it!

Makes sense. I did similar things in my backyard by hand, but that is only 1/2 acre, a few hundred feet of swale, and I thought that digging was an alternative to joining a gym. I would certainly turn to a machine if I wanted to do more.

Also, sometimes I plant trees in the ditch/swale, as our soil is so sandy. But I wouldn't advise that in soil that contained clay. If the swale is not exactly on contour, plug it up every so often so that the water doesn't all run to one side and overflow.