Nitrogen fixing plants for apple guild, where to buy them?

I've come up with a good list of nitrogen fixers for using with our apples in N California; does someone know of a good place to buy any of these, hopefully many in one place? Ideally in or near California?

Amur Maakia
Narrow leaf birdsfoot trefoil seed (this is more drought tolerant than common birdsfoot trefoil
Coulter arborescente (Bladder senna)
Baptista australis (blue false indigo)
Shepherd argentea (silver buffalo berry)
Lespdeza thunbergii - a bush clover
Elegysnus multiflora (Goumi)
Astragala (milk vetch, any)
Myrica certifiera - (waxmyrtle)

Gale

What about comfrey as a ground cover around the tree. I know it is a big biomass accumulator as well as a nitrogen fixer. Then there are the beneficial properties of comfrey itself. We use it as fodder for both poultry and goats. I think I bought it from Coe's comfrey.

http://www.coescomfrey.com/comfrey.html

I have no affiliation with Coe's, just happy with my dealing with them.

Thanks Lorens; I don't see comfrey listed anywhere in my sources as a nitrogen fixer. I do have it under many trees and will put it near the ones that don't have it.

There are quite a few plants that have a high protein content but unfortunately they like high-protein animal animals dont make it from the air they depend on legume+co doing the nitrogen fixing.

Brassica is the scientific name for turnips, and radishes. They actually have a higher protein content than many legumes, averaging 24% crude protein in our samples,
https://onpasture.com/2015/06/15/looking-for-high-protein-in-your-summer-mix-consider-brassicas/

eastern gamagrass ranks near the top in forage quality, testing up to 17% protein and 65% TDN
http://www.beefmagazine.com/mag/beef_eastern_gamagrass_queen

The spinach family has high level of protien and even "toxic" nitrate level, too.

Well a site that is used over on the west coast is:

https://onegreenworld.com/

Since I live in KY, its not terribly practical to have them ship to me, but you being in California it might be a good fit. They have a great selection of plants. Now lespadeza can be bought from co-ops and such from seed. It is rather expensive but because its perennial it will self sow into larger numbers. We have a lot of native lespadeza here on the farm. Also most nurseries should have blue false indigo, including Lowe's. Hope that helps.

Thanks Kevin and Benji,

I looked at the OneGreenWorld site; I'm glad to know of them in general. They do have one very promising looking plant, which they call Floaty Boat Pea Tree – Colutea arborescens. I'll also look into the others you mentioned.

I personally prefer Burnt Ridge. They sell a number of nitrogen fixers and I have found that they have good prices and quality in general. That's just my experience. I use primarily goumi and now, this year, siberian pea shrub for my nitrogen fixing in the orchard. I like to eat goumi berries, so I get a double crop that way. I hear that seaberries spread aggressively, which is why I haven't planted those. I haven't ordered from One Green World but will probably try them next year.

So your plan is to plant these and then do chop and drop several times a year?

Nitrogen fixers do this for themselves not for other plants unless you kill the nitrogen fixer plant so the stored nitrogen can become, through bacterial action, available to the trees.

I've found that a better way to get my trees the nitrogen and other nutrients they need is to increase the fungal hyphae and bacteria counts in the soil around the root systems by using good compost teas and mulching with good finished compost.
The Nitrogen Fixers are all dependent upon Rhizobium Bacteria, which are the nodule forming bacteria to fix their nitrogen for the roots to take up as needed, in turn the plant provides carbon in the form of simple sugars (exudates) to the bacteria.
There are three other major players (Azotobacter, Azospirillum and Clostridium) in the circle of nitrogen availability to plants as well as several fungal players, none of which are nodule forming which means the ammonium they make is available right now to the roots.
You might do better by using a dual set up, growing those nitrogen fixers for a living mulch cover crop and adding bacteria and fungi to the soil in the area of your trees roots, that way there will be available nitrogen all the time.

Redhawk

I second Burnt Ridge. They're very good.

James Landreth wrote:I hear that seaberries spread aggressively, which is why I haven't planted those.  

I can vouch for this.  I planted them in an area that my chickens have access to, and even chickens can't keep these things down.  I really like the berries, so the fact that they spread is awesome if you can keep them contained, but my 5 plants turned into about 105 after a year or so.

We seem to have an important difference of opinion here over whether  a nitrogen fixer next to a fruit tree will contribute nitrogen to it. Anyone seen any science on this?

I understand that roots die and grow regularly. Wouldn't a legume's root release its nodule  nitrogen when it dies?
 
Would a good compromise be to let the legume plant grow, cut it back, put the branches under the fruit tree. Then the legume would let a bunch of roots die, releasing their nitrogen, and the fruit tree would get the nitrogen from the dead roots and the legume branches.Does this sound right to you all?

I appreciated hearing about the other grower (whose name I can't now see above). If I'm confident about this way of working the the legumes, I'll shop with one or the other of your recommendations.

Todd Parr wrote:

James Landreth wrote:I hear that seaberries spread aggressively, which is why I haven't planted those.  

I can vouch for this.  I planted them in an area that my chickens have access to, and even chickens can't keep these things down.  I really like the berries, so the fact that they spread is awesome if you can keep them contained, but my 5 plants turned into about 105 after a year or so.

Must depend on the variety of seaberry. I planted around 12 of them a year ago and they have grown but so far I only have 1 new root sprout.

Another nitrogen fixer I would recommend are the native lupins I'm your area. I think sickle keeled lupin is found in northern California and it is drought resistant. There are other varieties in your area too. Most can be found from seed stores and just broadcast

There are at least 5 native types of lupins up here in Western Washington. I'm planting 4 of them this year and planted one type last year. The ones I planted are doing great and I'm getting volunteers showing up this year.

Just something to consider.

Lupines are beautiful and also fix phosphorus.
John S
PDX OR

Gale Zimmerman wrote:I understand that roots die and grow regularly. Wouldn't a legume's root release its nodule nitrogen when it dies?

This is my understanding based on observation growing lemon trees with and without neighbouring legume trees (leucaena leucocephala). These trees are my lynchpin for rehabilitating various plots and it seems to work, tho just the presence of other trees with their shade and biomass and windbreak could be as significant as any nitrogen fixing.

I had a neighbour rip out his leucaena "weed trees" along with yuccas, aloe vera, prickly pears etc cos they didn't give him conventional crop-like fruit which he wanted to receive all the limited water, and his garden started to resemble a desert.

Gale Zimmerman wrote:We seem to have an important difference of opinion here over whether  a nitrogen fixer next to a fruit tree will contribute nitrogen to it. Anyone seen any science on this?

I understand that roots die and grow regularly. Wouldn't a legume's root release its nodule  nitrogen when it dies?
 
Would a good compromise be to let the legume plant grow, cut it back, put the branches under the fruit tree. Then the legume would let a bunch of roots die, releasing their nitrogen, and the fruit tree would get the nitrogen from the dead roots and the legume branches.Does this sound right to you all?

I appreciated hearing about the other grower (whose name I can't now see above). If I'm confident about this way of working the the legumes, I'll shop with one or the other of your recommendations.

hau Gale, Since I am currently working on my PHD in microbiology and already hold BS and MS degrees in Biology and Chemistry I think you could probably take what I wrote as science of Legumes and Nitrogen fixers.
But incase you don't; nitrogen fixers can't do anything without the Rhizobium Bacteria, which are the nodule forming bacteria to fix their nitrogen for the roots to take up as needed.
This nitrogen is stored in the nodules the bacteria form as ammonium, which is the form of N that plants can use.
The only way to have other plants have access to that ammonium is to kill the nitrogen fixer so it rots and the ammonium is open for other plants roots to take up.

Redhawk

Just to add another source to this conversation...

New Mexico State University - Nitrogen Fixing Plants

Nitrogen Return to the Soil and Other Crops
Almost all of the fixed nitrogen goes directly into the plant. However, some nitrogen can be “leaked” or “transferred” into the soil (30–50 lb N/acre) for neighboring non-legume plants (Walley et al., 1996). Most of the nitrogen eventually returns to the soil for neighboring plants when vegetation (roots, leaves, fruits) of the legume dies and decomposes.

When the grain from a grain legume crop is harvested, little nitrogen is returned for the following crop. Most of the nitrogen fixed during the season is removed from the field as grain. The stalks, leaves, and roots of grain legumes, such as soybeans and beans, contain about the same concentration of nitrogen as found in non-legume crop residue. In fact, the residue from a corn crop contains more nitrogen than the residue from a bean crop simply because the corn crop has more residue left after the harvest of corn.

A perennial or forage legume crop only adds significant nitrogen for the following crop if the entire biomass (stems, leaves, roots) is incorporated into the soil. If a forage is cut and removed from the field, most of the nitrogen fixed by the forage is removed. Roots and crowns add little soil nitrogen compared with the aboveground biomass.

The above seems consistent with Bryant RedHawk's post. Got to chop and drop the nitrogen fixing plant or let it die and decompose naturally if you are going to get much benefit from it. Though from the above study there is a little bit of nitrogen transfer to the surrounding soil but at relatively low rates.

I did a quick Google search for average lbs of nitrogen added to crops per acre and while there are a lot of variables several sites listed the amount to apply to a corn field as well over 100 lbs of nitrogen per acre of corn. Several sites put it at over 200 lbs per acre depending on soil fertility.

So while there might be some leakage of nitrogen from nitrogen fixing plants it is at a low of enough rate that it is unlikely to have a massive difference. Especially, since we are just fitting in the nitrogen fixing plants where we can around fruit trees so we are likely not going to have the planting density that the above study tested (the study looked at a field planted with an alfalfa and meadow bromegrass mix - likely much higher density of nitrogen fixing alfalfa than the nitrogen fixers we would plant in a food forest).

Though if as Bryant Redhawk recommended you focus on improve the soil fertility by building the soil life and organic content then you will get nitrogen from other sources (soil life) than just the nitrogen fixing plants.

For my own property I'm planning my food forest to start with a lot of red alders mixed in with the fruit trees. These red alders will likely be grown by broadcasting seeds over prepared ground - hopefully prepared by chickens before hand which will also improve soil fertility. A couple years in I will significantly thin the alders and then add my fruit trees and some other edible plants such as berries, hazelnuts and herbaceous plants to the openings. The following year I will further thin the alders and eventually over 5 to 7 years I will cut down all the red alders though I may keep/add some Sitka alders since they grow as a shrub and should be able to take being chopped and dropped on a regular cycle (they normally grow in avalanche shoots and other sites that are disturbed on a regular basis). Though I need to test that and see if it works - can't find anything talking about Stika alder's ability to be coppiced.

I'm still working out the details on the above plan and won't actually implement it for a couple more years (need chickens first and I have some other projects to get through) but my hope is that by growing and then cutting down the red alders I will be able to build soil fertility quickly. Then by continuing to chop and drop the Sitka alder on a regular cycle I hope to continue to build soil fertility and help my fruit trees grow quickly.

There are studies done by the US Forest Service that show growing red alders alongside black cottonwood significantly increased the growth rate of the black cottonwood so I'm hoping that I can duplicate this but instead of growing black cottonwood grow fruit trees and other edible plants.