Keyline is a system of subsoiling in an *off*-contour pattern (starts above contour, goes below at the ridge). These rips in the ground serve to slow and add water, and air, into the ground, and spread it from valleys (where there's lots of water accumulating) to ridges (which tend to be dry). It can include building dams (in keypoints in valleys), and channels. Basically, you take a tractor with a subsoiler from the keypoints in valleys, and make long, subsoil rips towards the ridges surrounding valleys. Swales on contour are more of a permaculture thing; they are on-contour (meaning same elevation) trenches and berms that hold water. On top of them, usually a food forest with diverse species and layers of canopy. They too are a way of slowing, spreading and sinking water (and nutrients); but they primarily support the trees, bushes etc on top of the berm. Built on contour, usually it isn't necessary to consider primary ridges and primary valleys, since they tend to spread water equally (due to all being on same contour/elevation). The two systems are not mutually exclusive, but they do overlap in purpose and effects to an extent.
Enjoyed Jacob's case study. I've been adding trees to my pasture for years and specie selection/protection/layout are the three main concerns. Matching appropriate alley use to tree size is huge as well. He nailed it.
The last question they talked about tilling to dig a hole for trees. I used a 3 point post hole digger to dig about 20 holes to plant my trees. That was so easy and simple. I’m not sure how that would work planting 1000 of trees but it cut my time a lot.
I am planting walnuts in my sheep pasture. I used a ripper to rip a 10 meter N-S and E-W grid and planted the trees on where the ripline crosses. The soil was nicely broken up so I could easily plant just using a spade. This is flat ground, with the grid more or less perpendicular to the shallow slope.
