After plowing to loosen up the soil, a disc works well to expose large rocks that you can remove by hand (if it is an acre or two). After the large rocks >6" are removed, my rototiller does a good job of breaking up sod and exposing rocks >2". If the soil is dry enough and there is little sod clumps left, then my rock bucket, while slow, will remove >2" rocks without retaining too much soil.
At this point both the disc and the tiller has a tendency to bury rocks less than 1-2" and the seed bed looks nice. However, if I run over the seed bed at this point with a chain harrow (either the chain side or the aggressive side with tangs down), it will bring the small rocks back up to the surface. I borrowed a harley rake and while it can windrow small rocks fairly quickly on the surface of compact soil , with loose soil I wasn't that impressed. A lot of soil was mixed with the windrowed rocks that I removed with the loader. Might have been my technique, who knows.
When I removed a small gravel parking space and converted it to a deep flower bed I went with screening the soil as most implements only removed surface (1" deep or less) rocks. I box bladed off the top layer of gravel. Dropped the rippers and loosened the soil (glacial sand / gravel with a little loam on top), rototilled it to make it easier to move and screened out all the rock > 0.5" using a frame covered with 1/2" hardware cloth and angled at 45 degrees.
If I had a large amount of soil to screen I'd try to rent one of the commercial screeners like a
DeSite SLG-78 portable topsoil and rock screener or contemplate purchasing and then selling when done. They have a variety of screen sizes and options.
If you have real rocky soil, define a small rock as 2", and have lots of acreage, then a real rock picking implement like a
Rite Way rock picker or a
Rock-eze would be the way to go. Around here used ones show up at auction for $2k-6k and in need of some welding. They are amazing to watch in action and appreciate if you have been picking rocks by hand for years ...
