Hmmm, I know absolutely nothing about pastures except they're beautiful, but wouldn't a sub soiler be a bit too much disturbance? I have a subsoiler, and when I use it on my garden, man, that thing does some digging. I've seen in the Mississippi Delta country where they use a thingamajig that actually cuts way down deep, I think about 10' every 10' or so, and proved that it makes a big difference in the cotton crop. Bust up way down allowing moisture to penetrate better. I reckon for a pasture do y'all use those plug pulling thingmabobs that actually pulls a bit o' soil up leaving a hole?