Using the fava beans for both fixing nitrogen and for food at the same time.

Hello.

I am trying to come up with a crop rottation method that would involve rotating legumes (mainly fava beans) with grains ( I think mainly rye and corn for start). The aim would not only to grow food but at the same time grow high carbon material (straw) and material rich in nitrogen (legumes) and to use the legumes to boost the nitrogen in the soil. Only the problem is that the during seed formation the nitrogen fixed by the legumes is used by the plant. So if I was aiming for fixing nitrogen into the soil I would have to harvest the fava beans before they flower. So I was thinking how about growing the beans densely and at the point of 50% flower of the fava harvest 50% of the plants in the bed. Does anybody knows if that would have any signifficant effect on the soil nitrogen content?

You sound like you are are on the right track.

What happens when you chop and drop a fully fruited bean plant?
Does it waste the nitrogen? Or do you get it back in the soil through green mulch?

I like favas, but perhaps they can move patch year to year, while allowing larger quantities of other crops to seasonally fix N?

Good luck to your garden! And to YOU

So don't quote me on this if you're writing a thesis - BUT

My understanding is that the nodules fix nitrogen, most of which the fava uses for itself when it's putting on those big huge seed pods. So for max nitrogen you till it in right about when it's flowering. For max biomass you let it run it's course and eat as you like.

How about eating the beans and returning the pee to the soil?

Trevor Walker wrote:What happens when you chop and drop a fully fruited bean plant?
Does it waste the nitrogen? Or do you get it back in the soil through green mulch?

That was my first thought, but then it got to me that maybe I don't want to chop and drop half of the favas when the rest will be still growing to prevent pest problems.

My understanding is that the nodules fix nitrogen, most of which the fava uses for itself when it's putting on those big huge seed pods. So for max nitrogen you till it in right about when it's flowering. For max biomass you let it run it's course and eat as you like.

Yes I know, my poin is would it be possible to eat the favas and boost the nitrogen content in the soil by cutting 50% of the plants when they flower and let the rest go to seed. Would it help in any significant in the term of nitgogen concentration in the bed?

How about eating the beans and returning the pee to the soil?

This is concept for a market garden. I may not mind fertilizing with pee but that is still a taboo for many people.

If you harvest the bean at flowering then you naturally wont have any beans. I tried this last year with grains and it worked well.
Fava beans grow pretty big (you need to stake them otherwise they'll fall over and make your lodging problems even worse), and so just after flowering (the bees love them), I cut the plant off at ground level and removed the plant for composting.

With grains, if you introduce Nitrogen at the wrong time, you get too much green growth and not very good seed growth and so any Nitrogen additions should come early in the growing season.

What happened was that the beans didn't die like I expected. In fact it burst forth new growth and flowered again about a month later. It was too late in the season for them to develop beans good enough to eat, but it was good information.

It means that the fava bean self pruned its root system, releasing Nitrogen at the right time. It then continued to grow, accumulating more Nitrogen and storing it until after the grain was harvested. I then had a second Nitrogen harvest that went into the soil ready for the next growing season. It also provided a late bloom of flowers for the bees.

I'm going to do it again this year. The only thing to watch out for is wind blowing over the beans and damaging the grains.

Nick Kitchener wrote:If you harvest the bean at flowering then you naturally wont have any beans. I tried this last year with grains and it worked well.
Fava beans grow pretty big (you need to stake them otherwise they'll fall over and make your lodging problems even worse), and so just after flowering (the bees love them), I cut the plant off at ground level and removed the plant for composting.

With grains, if you introduce Nitrogen at the wrong time, you get too much green growth and not very good seed growth and so any Nitrogen additions should come early in the growing season.

What happened was that the beans didn't die like I expected. In fact it burst forth new growth and flowered again about a month later. It was too late in the season for them to develop beans good enough to eat, but it was good information.

It means that the fava bean self pruned its root system, releasing Nitrogen at the right time. It then continued to grow, accumulating more Nitrogen and storing it until after the grain was harvested. I then had a second Nitrogen harvest that went into the soil ready for the next growing season. It also provided a late bloom of flowers for the bees.

I'm going to do it again this year. The only thing to watch out for is wind blowing over the beans and damaging the grains.

Interesting. So you interplanted the beans with grain or grown grain after beans?

Nick Kitchener wrote:
Fava beans grow pretty big (you need to stake them otherwise they'll fall over and make your lodging problems even worse),

True/False. They do grow big. You do not need to stake them. Sometimes you need to stake them. It depends. I have grown lots and lots and lots without any staking.

Michal Malinowski wrote:

Interesting. So you interplanted the beans with grain or grown grain after beans?

Yes, I interplanted them. I'm looking for a legume to use that is friendly to the grains. Vetch tends to climb the stalks, bush beans tend to smother them too as they bush out.