posted 10 years ago
I would recommend leaving the stubble standing, assuming you will either broadcast the legumes or use a seed drill for planting. The stubble will reduce wind velocity and provide patchy shading, which will create a favorable microclimate for germination and growth of the young plants.
If the stubble is very dense, you could harrow the field lightly before seeding to knock down more of the residue and get the right density. If you post a photo of the field, I can give a better recommendation of whether a harrowing would be beneficial.