Nitrogen Fixing Species for Agroforestry Systems

Discussion in 'Planting, growing, nurturing Plants' started by permaship, Jul 1, 2014.

  1. permaship

    permaship Junior Member

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    I am currently working on an Agro-Eco design for a site in Todorovo, Bulgaria. The plan is to establish an Agroforestry system known as Alley Cropping wherein rows of mixed species edible trees and shrubs are planted at intervals with spaces for herbs, forage and/or grain crops to be grown in between. It's a dynamic system which is inherently diverse, providing multiple yields and excellent habitat for wildlife while at the same time being relatively resilient to a changing climate.

    I cannot fit the full article into this post so have left out vital info on the plants and the images. You can click on the link below to view the original post.
    https://balkanecologyproject.blogspot.com/2014/07/nitrogen-fixing-species-for.html

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    An essential component of the design will be the Nitrogen fixing perennial plants within the community of fruit and nut trees. These plants will be pruned at regular intervals to provide biomass for surface mulch and to release a biological source of nitrogen to the surrounding productive plants and soil life by means of root shed associated with top pruning.

    When selecting plants for the Nitrogen Fixing component of this design, I was looking for species that could withstand record lows of -28 (Zone 5), tolerate some shade, were fast growing, tolerant of trimming and coppicing, able to grow in clay soils, known to provide significant quantities of nitrogen, easy to propagate from seed and provide some food for humans and other animals. The following plants fit the criteria.

    • Elaeagnus angustfolia - Oleaster, Russian Olive
    • Elaeagnus commutata - Silverberry, Wolfberry
    • Elaeagnus umbellata - Autumn Olive. Autumn Elaeagnus
    • Caragana aborescens - Siberian Pea Tree
    We are planning to grow the nitrogen fixing plants for this site from seed and to involve the local community in doing so. Many local people, particularly the older generation are skilled horticulturalists with many seasons of experience behind them. We hope to include a large number of these people in the process of propagation, each one functioning as a individual unit. This will keep the propagation process small scale, making it far easier to use biological methods. The propagation will begin in the autumn as Elaeagnus spp. all require cold stratification unless they are sown immediately after they are picked. Caragana aborescens will be sown in the spring 2015.

    The Benefits of Propagating from Seed

    When I first started growing shrubs from seed I was pleasantly surprised at how fast the plants establish. In my experience from growing these and other nitrogen fixing shrubs, seeds germinating in the spring can establish well and be ready to plant out in the autumn of the same year (subject to species hardiness and, of course, the weather conditions in a given year). The following spring after autumn planting, I practice formative pruning to encourage the shrubs to become denser and by the third summer after sowing I have recorded growth of up 80cm high and 60cm wide specifically for Elaeagnus angustifolia . The growth I have witnessed from plants in my own stock have, in some instances, outperformed established 6 year old plants I have growing in the garden, purchased from a commercial nursery.

    When propagating from seed you have the advantage of selecting the strongest seedlings. Another significant reward is that you are promoting genetic diversity within your populations, something you are not likely to find in the majority of cloned nursery stock.

    If you would like to grow your own nitrogen fixing plants we are have a supply of excellent seeds at very reasonable prices currently only available to our blog readers. Visit our blog for more details

    Plants Profiles for the Nitrogen Fixing Component of this Design.

    Elaeagnus angustfolia - Oleaster, Russian Olive


    Uses: Edible fruit -raw or cooked as a seasoning in soups. The taste is dry sweet and mealy. The oval fruits are about 10mm long and contain 17 amino acids with total sugars making 54%of the composition. In China they are made into a beverage
    Expected fruit yields are 7-9kg per plant. The seed is edible raw or cooked. The seed oil, flowers and leaves are used medicinally. Plants can be grown as a hedge in exposed positions, tolerating maritime exposure. An essential oil obtained from the flowers is used in perfumery. A gum from the plant is used in the textile industry in calico printing. Leaves are used as goat and sheep fodder. The wood is hard, fine-grained and used for posts, beams, carving, domestic items and makes good fuel. The plant is attractive to bees and is known to be grown as a biomass crop on a 3 year rotation. In Pakistan it is valued as a pollard fuel and fodder crop.

    Nitrogen Fixing Potential: This specie is classified by USDA as being a HIGH nitrogen fixer with estimated yeilds of 160+ lbs/acre or 72>kg/4050m²

    Propagation:Establishment and reproduction of Elaeagnus angustifolia is primarily by seed, although some spread by vegetative propagation also occurs. Cold stratification required for 30-60 days.

    Elaeagnus commutata - Silverberry, Wolfberry


    Uses: edible fruit, raw or cooked, good with soups and for making jelly. Edible seed, raw or cooked. Plants can be grown as a hedge in an exposed position, tolerating maritime climate. The fibrous bark is used in weaving and rope making. Dried fruits are used as beads. Flowers provide nectar for bees. Cultivated as an ornamental plant for its silvery foliage.

    Nitrogen Fixing Potential: The species is classified by USDA as being a MEDIUM nitrogen fixer with estimated yeilds of 85-160lbs/acre or 39-72kg/4050m²

    Propagation: Seed is best sown as soon as it is ripe in a cold frame. It should germinate in late winter or early spring, though it may take 18 months. Stored seed can be very slow to germinate, often taking more than 18 months. A warm stratification for 4 weeks followed by 12 weeks cold stratification can help. The seed usually (eventually) germinates quite well.

    Elaeagnus umbellata - Autumn Olive. Autumn Elaeagnus

    Uses: Edible fruit raw or cooked which is very tasty and can be made into jams, preserves etc. The fruit contains about 8.3% sugars. 4.5% protein. 12mg per 100mg Vitamin C. Mature bushes in the wild yield about 650KG of fruit over 2-3 pickings . The harvested fruit stores for appox. 15 days at room temperature. It can be used as a hedge plant and tolerates maritime exposure succeeding in the most exposed positions. The wood is a good fuel. The nectar from the flowers is attractive to bees comprising 28% sugars. The plant is used as a nurse tree, when planted with fruit trees it is reported to increase the overall yield of the orchard by 10%. It can also be grown as a biomass crop on a 3 year rotation.

    Nitrogen Fixing Potential: The species is classified by USDA as being a MEDIUM nitrogen fixer with estimated yeilds of 85-160lbs/acre or 39-72kg/4050m²

    Propagation:Seed - best sown as soon as it is ripe in a cold frame. It should germinate in late winter or early spring, though it may take 18 months. Stored seed can be very slow to germinate, often taking more than 18 months. A warm stratification for 4 weeks followed by 12 weeks cold stratification can help. The seed usually (eventually) germinates quite well. Prick out the seedlings into individual pot as soon as they are large enough to handle and plant out when they are at least 15cm tall.

    Caragana aborescens - Siberian Pea Tree

    Uses: The young pods are eaten as a vegetable, lightly cooked. The pods become tough later in the season. The seeds are rich in fats and proteins (12% and 36% respectively) about the size of lentils and can be cooked and used in any way that beans are used (the cooked flavour is somewhat bland, so best used in spicy dishes ). The young raw seeds have a pea-like flavour although it is not clear whether they should be eaten raw in much quantity. Widely used in windbreaks and shelter belts and used in wildlife-erosion control plantings stabilizing soil with an extensive root system. Good wildlife fodder and can be used to as poultry food. A fiber is obtained from the bark and used for rope making.

    Nitrogen Fixing Potential: The species is classified by USDA as being a MEDIUM nitrogen fixer with estimated yields of 85-160lbs/acre or 39-72kg/4050m²

    Propagation: Seedpropagation is the norm. Seeds germinate better after a short period of stratification and/or soaking in warm water prior to planting.

    Cheers ,

    Paul

    https://balkanecologyproject.blogspot.com/
    www.balkep.org
     
  2. eco4560

    eco4560 New Member

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    Great report Paul! Thanks for sharing your progress.
     
  3. Tasman

    Tasman Junior Member

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    Excellent read! Thank you.

    Your blog is also well worth a visit. There is a lot of information there. I especially liked the guild article and the plant list.

    cheers,
    tas
     
  4. abdullah

    abdullah Junior Member

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    any chance i could get this in pdf?

    edit:
    i need to analyse several reports as part of my horticulture studies, i'd prefer to do interesting things like this :)
     
  5. andrew curr

    andrew curr Moderator

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    As you are in the neigbhourhood may i suggest you get over to Hungary and obtain some shipmast locusts (Robinia pseaudoacacias) they apparenty have selected cultivars and if you are after legumes go with selected cultivars unless you are chasing biodiversity !
    Tas im exited!
     
  6. chook-in-eire

    chook-in-eire Junior Member

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    Excellent post indeed.
    I too grow Elaeagnus here in the West of Ireland (E. umbellata, E. angustifolia) as a hedge species, support species for fruit, cut&bring browse for goats, food source for our bees and other pollinators. We get fruit only occasionally. This year looks good as we had good weather during the flowering period. I will plant more this autumn in a mixed linear planting with crabapples and elderberries. Caragana unfortunately does not like our climate.
     
  7. permaship

    permaship Junior Member

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    Sure Abdullah, send me an email and i'll post it over to you. [email protected]

    Cheers

    Paul
     
  8. permaship

    permaship Junior Member

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    Thanks for the tip Andrew.
    There is actually a good stand of Robinia pseaudoacacia already on the site, mainly in the hedgerows but starting to run towards the land marked for crop cultivation. I would like to prevent it from spreading and manage it to produce poles for the future as well as biomass from the thinnings for use as mulch. I leaned away from using these trees amongst the fruit and nut crops as they are not shade tolerant.
     
  9. sweetpea

    sweetpea Junior Member

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    Hey, Paul, looks like a wonderful project. For what it's worth, and I guess most here know I like to be a realist, not a total optimist (but what is farming if it isn't complete optimism and belief in the Powers That Be) and I've lost a lot of years, and caused myself a lot of depressing labor undoing what I thought/planned/researched ought to be just great. I think it's a little deceiving about nitrogen fixing perennials (and annuals.) Maybe my experience can be of some help. I'll sum it up in a list, because this is getting a bit long!!!

    1. Fruit trees don't need access to nitrogen all year long, only during their growth period.

    2. I haven't found nitrogen-fixing perennials or annuals to ever be enough for a fruit orchard, it requires manure (which has lots of nutrients in it, but only during the growth period) and lots of compost rock powders/sands and mulch the rest of the time.

    3. Compatibility in the root zone. Drought-tolerant, nitrogen-fixing perennials roots will extend out to all that water and nutrients around a fruit tree and invade a fruit tree's space. Fruit trees don't want competition from perennials. Annuals are easier to control.

    4. Nitrogen-fixing plants do use nitrogen and other nutrients, so they will compete with other plants to some degree. Fruit trees can be really fussy about how big of a crop they put out. It's only when the annual nitrogen fixing peas/beans/vetches are mowed away and the pinhead-sized nodules are allowed to break down, in 6 months to a year depending on soil conditions, that the nitrogen is there for another plant.

    5. I have found blooming perennials and annuals to be much more beneficial for a fruit orchard.. They bring in beneficial insects and birds.

    6. Lots of air flow around a fruit trees keeps the leaf diseases away. Lots of shrubs would block this.

    7. I like to mow away the weeds and grasses (that will compete with and actually kill fruit trees) because it's quick and makes great mulch.

    8. I have Silverberry elaeagnus and they have giant, painful spikes, does not bring in as many beneficial insects as a blooming plant would. The first year of trimming was fun. After that it was just a lot of work!!

    9. I don't know what "medium nitrogen fixing" means but it doesn't sound like enough. I have seen charts for annuals that fix nitrogen, listing pounds per acre of nitrogen, but when a mature fruit tree needs nitrogen it needs a lot right then, not 3 or 6 months later.

    10. Walnuts put off growth inhibitors not only in their roots but in the green-turning-black husks that cover the nuts. They should be off by themselves and very far apart from each other in a Food Forest setup so there can be lots of biodiversity between them.

    11. A lot of people are allergic to acacia pollen.

    12. If you want to interplant between fruit trees, don't do it all at once. And try a few different plants, not all the same type. Leave some places empty for future experimentation. Elaeagnus are great, but biodiversity is more helpful. Blooming hydrangeas, honeysuckles, herbs, annual bloomers, catnip (stunning beneficials come for this), borage, parsley left to bloom, buckwheat. if you change your mind with annuals it's easy to get rid of them. Perennial rye grass, for me, has been a real nightmare to get rid of.

    13. If I could do it over with my 90 fruit trees I would plant them twice as far apart as conventional distances say, and plant a row of blooming annuals and perennial flowers to bring in beneficial insects and critters to help. I like to keep the area under the fruit tree free to walk and mow easily underneath and mulch it heavily out to the dripline. Makes for quick picking and easy access up into the tree.

    14. I would install a design plan in a small portion of the property and see how it evolves. It will change according to what works for your location and for your psychological happiness, the way you want to do things. Putting in fruit trees is a huge investment in time and money, and to find out 5 years later it should have been some other way is a real disappointment, exhausting work undoing it, and sometimes even fruit trees are lost.

    I am closer to making my orchard suit not only my plants, but me, too. It is more efficient and uses lots and lots of biodiversity. Some things work, some things fail, some things burst into life that completely surprise me. That is what we are looking for, compatibility for where we are. :)
     
  10. sweetpea

    sweetpea Junior Member

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    Edit on Number 9:

    I see your lbs/acre on the elaeagnus but that involves shoulder-to-shoulder planting of a nitrogen fixer perennial that is using that nitrogen for itself. 10 percent isn't enough of an improvement, considering the work involved in controlling a shrub like that. It probably wasn't the nitrogen that improved the crop, )(nitrogen only improves growth) It might have been the mulch dropped by the elaeagnus providing potassium and phosphorous, or the weather, or the rainfall, or a year of good bee pollination.

    Maybe there's more information on that study? :)
     
  11. sweetpea

    sweetpea Junior Member

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    After watching this YouTube film on a Permaculture orchard I might stand corrected about the nitrogen fixing shrubs competing with the fruit trees. This is inspiring.

    https://youtu.be/3riW_yiCN5E

    This guy says he hasn't added fertilizer (I assume he means manure) for 7 years, and I would dearly love to not have to haul and shovel manure. Although I think there are wonderful extras in manure that do good things.

    Maybe, too, in my situation, where we have no summer rain, the breaking down of nitrogen is slowed. And now with drought and even drier conditions, that could be why I am not seeing major results with only using nitrogen fixers. But I do love the biodiversity at Miracle Farms

    For my situation I want to stick with natives that fix nitrogen, since I won't be here forever to keep things in check :)

    In looking for biodiversity in nitrogen fixers I found these that bloom:

    French honeysuckle
    Blue Wild Indigo (Baptisia australis)
    and other Baptisias
    Siberian Pea Shrub
    Ceanothus (all)
    Lupinus (all), Lupine
     
  12. Pakanohida

    Pakanohida Junior Member

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    Wisteria, the lovely vine with awesome flowers that makes me chooks & humminbirds so happy on a daily basis is also nitrogen fixing. A Cold snap during this summer has actually caused it to bloom a 2nd time this year.
     

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