Well, I have a conundrum. The more I read about tilling, perhaps I shouldn't be doing so every year, but... I have been adding my city's compost and well rotted horse manure for many years. Every year I till my veggie plots before planting. Every year my soil seems as hard as before. Today I spent 3 hours turning over soil in one plot and breaking up the clods with the shovel. I only turned over 6'X 4'. It is so rough, I don't know how I would plant seeds there. Folks, I'm 68 years old, and an active female, but this is nuts! I'll never get the friable soil I dream of this way. So, do I keep adding stuff and keep tilling? Perhaps I should till only shallowly instead of as deep as I can go with my Mantis. The topic might bring a storm of tillers and non tillers, but I'd like input here. I want soil that crumbles in my hands! You know - Martha Stewart soil!
There are 30 steps from my driveway to the garden, but I'm willing to spend more money to get what I want. The compost and manure is free, but not the labor to get it up to my garden. All your help is appreciated.
I'm paralyzed from the waist down, and the native soil here is gooey, thick clay. Since I can't run a rototiller, I cheat.
My first tactic is to build raised beds, because it's easier to pile good raw materials on top of the clay than it is to incorporate it into the clay.
Next, I plant cover crops wherever I want to really bust up the clay & bring minerals up from below. Clovers are very good at driving their roots very deeply into the subsoil. This opens up channels for water & microorganisms to get down there & expand those pathways. I also plant Daikon radishes in the nastiest clay patches, & I never pull them; they rot in place over the winter & leave big holes behind.
At the same time, I scatter all the spent coffee grounds I can get my hands on. It's like ringing the dinner bell for worms. Worms do a fantastic job of aerating soil, and they leave behind castings that plants love.
I didn't get good soil quickly, but I did eventually get it. Now I just maintain the conditions needed to keep forming more: plants on top, plant litter & organic matter at the surface, occasional water, and that's it. Worms & microorganisms do the rest for me.
I thought that enough compost and manure would soften anything, but I noticed that my clay stayed gooey when I only added compost. Then I added coarse sand, and that seemed to make it more friable, even though many people say "sand doesn't help clay".
Now I add medium pine bark mulch, screened if I have the time and energy. And sand if its in the budget.
You might think about mechanical compaction and drainage.
If you walk on top of soil with any clay in it, it probably will pack down hard and tight.
Especially if you walk on them when wet.
Make narrow beds, and ALWAYS walk around them, never ON them.
Since walking around a long bed takes time, make them narrow and fairly short.
3x15 feet? 2.5 x 20 feet?
You can even till "from the side" though it is harder.
If narrow enough, and some of the plants are short, you can step over them. Or set two cinder blocks on their sides in the center as a stepping stones.
It's better to have 50 square feet of GOOD aerated soil than 150 square feet of hypoxic clay pudding.
Even heavy rain seems to pound clay down into a harder state. Keep some coarse mulch on top. Pine bark mulch has become my hero.
Wet clay is hopeless - you want very good drainage. At least you have a slope! Why does that argue against raised beds? Think of them as terraces.
If you have great drainage, the soil won't stay as wet as long. That may encourage to compact itself less over the months.
This is speculative, I haven't built beds on anything this steep, but I've been thinking about it for a steep, shady spot I have.
Chop a WIDE staircase into the hill, where each 'step' is a rasied bed. You might use the removed soil to form the next step down, probably adding manure, compost, sand, crushed rock or bark as you go.
Or, if you have infinite energy or helpers, wheelbarrow it away to somewhere you can screen it and amend it before bringing it back.
(And consider filling the new beds or the top half of the new beds with much better imported soil or LOTS of organics. Like 3-5 parts compost and amendments to one part clay. The lasagna method of building soil lays down corrugated cardboard or many layers of newspaper on the floor, before adding lots of organic material.)
Each step or raised bed would cut into the slope 4-6 feet, for a bed 3-4 feet wide and a walkway 1-2 feet wide. Depending on how far you're willing to walk to get around each bed, maybe run them for 15-20 feet of length (this dimension is at a constant height on the hill; I'm not explaining this very well). Probably start with just one bed near the top of the slope.
You want a 1-2 foot wide walkway BELOW each bed, so you don't have to stoop as much.
If the walkway is BELOW the 'floor' of the bed, it has better drainage, especially if your lower walls have some holes or notches on the bottoms, or you chop a few drainage cuts where the floor of the bed meets the RB wall.
The "floor" of each RB should be mostly level, so the RB has fairly uniform depth, but should slope downhill just a little for drainage. Maybe just an inch or two of drop over 2-3 feet of bed width.
The wall on the downhill side ought to be 8" to 16" high, so you have some depth of soil.
If your base, unimproved clay is hard enough to be a structural material, the uphill wall might be partly or all clay (like the riser of a staircase). Since the upper wall of one bed would merge into the walkway of the bed above it, that should stay packed pretty hard!
I think the slope of your hill and width of bed plus walkway determines whether the uphill wall is all clay, or clay plus a short wall. One nice thing about RBs on a steep slope: you might only need half as many walls!
I like paving stones stood on end and tilted back an inch or two into the bed for stability. I don't need stakes - they lean on the soil. It also motivates you NOT to walk on the soil in the bed! That tends to topple walls and maybe send you rolling downhill!
An 8x16" paver lets you have an 8" depth, or a 12" depth. But the 12x12" pavers are thicker and give more stability. Either costs around $1 where I live.
Depending on slope, you might have 12" or 16" lower walls, but 4-6" upper walls. Thent he upper walls could be one wooden board, and the lower walls paving stones (or 2-3 boards nailed together).
If you need or want to till with a machine, you can take paving stone walls down, lay them on the walkway, and put them back up easily. I till with a gardening fork and a "sharpshooter" spade. It has a long, narrow blade that goes down 14-16". But once the soil gets soft enough that worms don't need jackhammers to penetrate it, and has enough 'structure' to drain well enough to let air in, I seldom till deeply.
If I can find something I like that grows in deep shade, one of these years I'll let you know how this scheme works in practice! Until then, I hope you can turn your clay into soil!