This past spring I planted broccoli rows between my bush bean rows and it has worked out well. The broc is now gone and pulled out as the beans filled in the gaps and are now being picked for the first time today. Each year I plant green peas in rows and once done pull them up and plant corn right behind them hoping that left over nitrogen is still in the soil. Seems to work ok though I still do fert the corn as it grows.

The tomatoes will need much more nitrogen than the legume plants can supply, so I would not count on them alone to supply the N needs.

What I have always heard and from what I have read about it, it only works if you leave all the bean roots with the nodules on them in the soil or if you till in the bean plans roots and all. I know that is the case with legume cover corps.

Link below is to a study out of New Mexico State Univ. on the amount of nitrogen contributed to the soil that is usable by subsequent crops

The amount of nitrogen returned to the soil during or after a legume crop can be misleading. Almost all of the nitrogen fixed goes directly into the plant. Little leaks into the soil for a neighboring nonlegume plant. However, nitrogen eventually returns to the soil for a neighboring plant when vegetation (roots, leaves, fruits) of the legume dies and decomposes..

Dave

Here is a link that might be useful: Nitrogen Fixation by Legumes

I never knew that, Dave. Thanks for the info!

10 to 1 diluted urine can provide nitrogen, it is organic too

Understand that legumes "fix" nitrogen in the soil that is already there. While growing, they are not to be considered a source, but rather biological agent that makes various forms of nitrogen already in the soil available to other plants. If you mulch them afterwards, then yes you will get additional nitrogen like you would from any other green mulch.

The amount of N fixed in most popular edible varieties of peas/beans is quite low, and once you let them fruit it becomes even lower.

It's better than nothing, but it's not a concentrated enough N source to be more than a minor help in your fertilizing regimen.

If you're looking organic + readily available + cheap, blood meal gives good bang for the buck for N.

nc-crn, I agree completely. However we have two sectors of the organic gardening culture who will not use blood meal: (a) those that fear pharmaceuticals in beef, and (b) those from the Hindi culture who want nothing to do with slaughtered beef. For these groups, organic (non-inorganic) sources of concentrated N become more narrow, basically down into the 5% to 6% concentration range.

Tomatoes do not need much nitrogen, if they have it, they grow very bushy and green, but do not produce well. I always rotate tomatoes with zucchini, cucumbers or corn(just for rotation purpose), where LAST year I applied manure, and do not apply anymore nitrogen whole season long, and they still grow a bit bushy to my taste, but at least they produce).

I have not tried it with tomatoes, but last year I tried it with onions, letting clover grow between them instead of mulching them with hay. (can you say "lazy"?) I got small onions, and the info above has explained to me why, because of course the clover was still growing.
Maybe if I'd mulched heavily over the clover and killed it, then it would have helped? Though I've also heard that clover only fixes N in its second year of growth? Oh, if these plants only knew how detailed we get in taking care of them!