I put a mix of tritacale,oat, two or three peas, and vetch under my walnuts this last winter. That soil is completely different this year. I had major compaction issues going on and that solved it. In fact it worked so well I had a hard time getting water across the whole thing. The trees look a little healthier as well but I won't be able to tell if it helped production until next year as the trees decided what this years crop would be before I planted the cover crop.
An interesting side note: I incorporated the crop into the soil at about fifty percent bloom on the vetch and the peas had already bloomed. I had green lacewings and lady beetles BOILING out of there. I have a block of citrus and a block of pecans across the road from those walnuts and neither of them had to be sprayed for any thrip, aphid, scale, nothing. I also never sprayed for walnut husk fly and I'm one of very few growers who din't have a problem with them this year. Now I'm toying with adding flowering crops into my IPM program at specefic times just to boost my beneficial insect populations.
