Last year, my husband designed a subsoiler to help improve our pasture soils, based on P.A. Yeoman's keyline and subsoiling principals. We have been eagerly awaiting good weather and moist soils to try it out. This past weekend, we got that weather, the ground was thawed, and soil was moist enough. So we hooked it up and tried it out. We hitched our two big Belgian boys, and the subsoiler roughly 6 inches into the soil. In our hard, thick clay soils and virgin ground, the boys seemed to pull with the same force as would be required from a 12 inch plow in broken ground, for what it's worth. Hubby is going to make a few changes to the subsoiler, but for the most part, we were pleased. Now I just have to perfect my keyline patterns and subsoiling techniques! Here are a few photos, and some YouTube links for anyone interested in video and more explanation.