Yes, I sometimes use well-rotted steer manure at least a month before I plant. This gets the soil well-aerated and friable and mixed in with the manure from tilling, rain, and the other elements like frost; and it is well incoporated. I usually plant in autumn anyway so have a good crop by the time spring comes. I also use a good plant based additive made up of composted grapes, and apples and other vetatative goodies.