We have learned much more about nitrogen fixation since this was published 2014 – Read this plunge first!
One of the key roles in the establishment of a forest garden is to provide the conditions for creating and maintaining their own fertility. In a previous post I wrote about Dynamic accumulators taking up minerals from deep soil layers and making them available to other plants. Although these minerals are essential for plant growth, is the nature of the rule the nutrient nitrogen is the limiting factor. In order to maintain a healthy growth of the plants in a forest garden, it is important to meet their needs for nitrogen, which primarily occurs through nitrogen-fixing plants. These plants symbiotic bacteria that has the ability to fix nitrogen from the atmosphere and can make it available for the plants in exchange of nutrients such as carbohydrates. The bacteria live in nodules attached to the roots of plants.
The nitrogen fixed may be other, non-nitrogen-fixing plants benefit in several ways. During the growing season, it is mainly with the help of fungi that nitrogen is distributed in the forest garden. In a living soil, there are plenty of fungi with their hyphae (fine strands forming the fungal building blocks) connects various plant-root systems. The difference in concentration of nitrogen at different ends of hyphae allows the nitrogen automatically migrates from the nitrogen-fixing plants to those that do not have this ability, Thus from areas where there is plenty of nitrogen to areas where there is a lack of nitrogen. Because nitrogen is moved in the hyphae there is no risk of nitrogen leaching. The mushrooms also get nutrition in the form of carbohydrates from the plants thanks for the nitrogen they provide them with.
The nitrogen is also made available to other plants in the fall when the woody kvävefixerarna release their nitrogen-rich leaves and when the herbaceous kvävefixerarna dies down. This nitrogen runs slightly more likely to leach out and moreover it is not the fall nitrogen is needed most, but in the spring and early summer when the plant's growth occurs. A living soil with good interaction between microorganisms is thus indispensable for achieving the goal of self-maintaining fertility.
What plants are there for our climate that can help add nitrogen to the nutrient cycle in forest garden? The list below summarizes the Martin Gustafsson has made. It includes nitrogen-fixing tree, bushes, creepers, perennials, Bienne (perennial crops) and annuals (annual plants) with their names and where we have found the information even their nitrogen fixation ability. For woody plants also indicates resistance. The list includes such nitrogen-fixing plants that we find most useful in a forest garden context and of course there are many more kvävefixerare going to grow in Sweden. There are still some question marks remain and we are grateful for comments and additions!
| Scientific name | Swedish name | English name | Resistance | Nitrogen Fixation Ability | |
|---|---|---|---|---|---|
| Tree | Alnus glutinosa | European alder | Common/European Alder | Zon IV/V | high |
| Gleditsia triacanthos | Honey locust | Honey Locust | Zon III (IV) | ||
| Gleditsia triacanthos 'Inermis' | Honey locust | Honey Locust | Zon IV | ||
| Robinia pseudoacacia | Robinia | Black Locust | Zon III | medium | |
| Shrubs | Colutea arborescens | Blåsärt | Bladder senna | Zon III | creations data |
| Caragana arborescens | Sibirisk ärtbuske | Siberian Pea Shrub | Zon VIII | medium | |
| Cytisus scoparius | Harris | Common broom | Zon III | high | |
| Elaeagnus multiflora | Japansk silverbuske | Goumi | Zon III ? | ||
| Elaeagnus umbellata | Korean silver shrubs | Autumn Olive | Zon IV ? | medium | |
| Genista tinctoria | Färgginst | Dyer's greenweed | Sun V | ||
| Hippophae rhamnoides | Havtorn | Sea Buckthorn | Zon YOU | medium | |
| Myrica gale | Fears | Bog Myrtle | Zon YOU | low | |
| Myrica pensylvanica | American track | Bayberry | Zon VII | ||
| Shepherdia argentea | Bisonbuske / Buffelbuske | Buffaloberry | Sun V | medium | |
| Twisted | American apios | Potatisböna | Ground Nut | Least Sun IV | medium |
| Lathyrus latifolius | Rosenvial | Everlasting pea | Least Sun IV | ||
| Vicia pisiformis | Ärtvicker | Pea Vetch | Least Sun IV | ||
| Perennials | CLOVER | White clover | White Clover | high | |
| Trifolium pratense | Red clover | Red Clover | medium | ||
| Lotus corniculatus | Bitch Tooth | Bird's Foot Trefoil | medium | ||
| Galega officinalis | Getruta | goat's rue | |||
| Astragalus glycyphyllos | Sötvedel | Milkvetch | |||
| Perennial Lupinus | Gruslupin | Sundial | |||
| Trifolium medium | Forest Clover | Zigzag Clover | |||
| Medicago sativa | Blålucern | Alfalfa | high | ||
| Bienne | Melilotus officinalis | Yellow melilot | Ribbet Melilot | medium | |
| Anueller | Trifolium subterraneum | Subklöver | Sub clover | medium | |
| Lupinus angustifolius | Blålupin | Blue Lupin | high |
I want to add gray alder that bind nitrogen as alder, but has the advantage that it thrives in a much larger part of the country.
Hi! Completely true that gray alder is hardy, but its drawback is that it sends out suckers and thus can easily take over a forest garden. Klibbalen shoot just ordinary shot and stays on so we place. Therefore, there Grail is not on the list.
Hi! First: thanks for table Philipp, very informative written!
Subject alder: I still fairly limited knowledge about forest garden design, but thought I'd share with you my experience of alder in 60 old deciduous forest in a northern Aravin. Which I have not experienced that Grail shoot much suckers, or that it has taken over. Rather, it leaves room for other trees and shrubs (som asp, björk, hägg, raspberries, Currants). I would also guess that “Chop and drop” would work out in a northern forest garden situation on the Grail should happen to become invasive. An advantage of Grail – except that it is much hardier than alder in Norrland, is that it is relatively drought resistant and thus can be included for example to improve degraded soils with shallow root systems (old lawns on compacted soil, tex). Grail tolerates also pollarded, although it is a bit more sensitive than eg. alder and willow.
Greetings January
Thanks Jan for sharing your experience!
Read that in the United States warned of Elaeagnus umbellata because it proved to be invasive, takes over poch displaces other vegetation partly through shadows
http://www.nature.org/ourinitiatives/regions/northamerica/unitedstates/indiana/journeywithnature/autumn-olive.xml
Have just received two pieces of inspiration of your blog and get worried now. What do you think about this?
Greetings, Joanna
Hey Joanna,
whether an alien species are invasive depends very much on including climate and the locally occurring plant- and wildlife. Right Silver Bush has no such tendencies in our climate, it's probably too cool for it to become a problem. There are other examples, as wolfberry (Lycium barbarum), and even that of our very modest bitter anchored no (Lepidium leaved) which are invasive in warmer climates. Unfortunately what I have seen no comprehensive list of invasive species, but the s. 6-9 in this article, it is pretty good about invasive species in general (some examples): https://www.slu.se/Documents/externwebben/overgripande-slu-dokument/miljoanalys-dok/populart/miljotrender/2014/SLU_MT_augusti_2014_webb.pdf. Here in Dalarna there are a few species considered invasive, but it varies greatly from county to county also: http://www.lansstyrelsen.se/dalarna/Sv/djur-och-natur/hotade-vaxter-och-djur/invasiva-arter—alien to-animals-and-plants-in-the-nature / Pages / default.aspx.
Please
Philipp
Hi!
Do you know if Maackia amurensis also kvävefixernade?
According to the Plants for a Future will Maackia amurensis be nitrogen-fixing.