Fixing Sandy Soils

Discussion in 'Planting, growing, nurturing Plants' started by wenshidi, Jun 18, 2010.

  1. wenshidi

    wenshidi Junior Member

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    I was reading a transcript of one of Bill Mollison's PDC courses this morning and he said " There are only two occasions when you do not use a Wallace Soil Conditioner and one of those is very free sandy soils."
    Wouldn't you just know it, I have very free sandy soils, but he does not go on to say what solution is suitable for me.
    The sandy soil that I am looking at is the remainder of what is left from clear cutting tropical rainforest and having all the good organic stuff washed away. In places the jungle has been replaces by rubber and palm plantations but the soil has not really improved. There are also a lot of very steep slopes. The underlying rock is volcanic with large outcroppings in inconvenient places.
    What should I be doing to get this sandy soil back to its original fertile state?

    Chris
     
  2. Tropical food forest

    Tropical food forest Junior Member

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    First you have to understand that the soil was probably never fertile

    most of the fertility would have been held up in the biomass, which is now exported, eroded or volatilised

    primarily you need to cover it with something, anything
    use some fertiliser to get t going if you need to

    you may want to use some fast growing Pioneers to rebuild biomass
    in soils like this the forest grows on the fallen forest
    Fraser island is a sand island that supports tall tropical forest, but only by nutrient recycling

    it will be very hard to be sustainable for any export agriculture on soils like this. Maybe impossible
    and hard to manage for susuatinable susbstistence

    where are you in the world?
    if in the west then species like cecropia
    if in the east then good early pioneers are species like Acacia, Macaranga and Hibiscus

    you are going to have to plug the sink hole first
    then refill the bath slowly

    also youd have to look beyond Nitrogen to other issues like subsoil acidification
    you may have to import Calcium and magnesium, and incorprate deep rooted subsoil recyclers and scavengers
    luckily some crops have quite low requiremnets
    Avocado and Cacao are not hungry crops for example
     
  3. Tropical food forest

    Tropical food forest Junior Member

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    Also Biochar may help

    can you access the fronds or shells fragmnets from oil extraction?
    these would make a good Biochar

    Research on sandy soils and biochar in Vietnam is looking positive

    they are also using Casuarina to stabilise erodible slopes, it has a fine foot network that binds the soil, and self mulches
    it fixes its own nitrogen via an actinomycete partner
    it coppices well and makes excellent charcoal

    Vetiver grass is another for that purpose but mainly for engineering works and in fields
    as it is not shade tolerant

    im happy to assist with info if you need
     
  4. Tropical food forest

    Tropical food forest Junior Member

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    whats this volcanic subsoil look like?
    does it have a clay fraction?
    if so you can mine it and use it to ammend the sandy soil
    just a fe % clay REALLY helps

    i used to garden on pure sand in WA
    its actually ok!

    the biggest problem is nematodes
    a problem that deserves it own forum!

    you always keep the soil covered
    never dig in muclh
    and add clay

    upsides is you have excellent drainage, so less root rots
    and excellent growth rates on trees because roots can easily and quickly penetrate deeply

    Palm oil and Rubber are good starting points for complex agroforests
    add legumes, fruits, nuts, coconuts, bamboo, animals, medicines and you have a real ecosystem developing
     
  5. charlesinnaloo

    charlesinnaloo Junior Member

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    Its such a good long term solution on the large scale but for a backyard garden beds i.e. high output, I am now using Wicking Worm Beds, these allow water and nutrients to be contained in the system, which is impossible in the short tem on sand. So you might want to do most area in the long term technique and if you want a short term garden look up this stuff and have a go. Sand is a good medium in these beds, so you only need to add say 30% carbon stuff (compost/manuse), keep it organic otherwise you will have salts and other toxin bulidup as they are essentially closed systems.
    I have the surface mulch level of my beds in line with the surface mulch level of the surronding soil, that way soil microbes, worms and other things can migrate in and out of your beds via that layer, this allows some loss via wicking out the mulch layers but most of the water is still contained in the bed.

    Anyway check www.waterright.com.au and their suggested links. Open wicking beds are also and attractive option for shortcutting the soil improvement cycle.
     
  6. matto

    matto Junior Member

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    I have seen in a Biodynamic Journal that using BD practises, and i would assume cowpat preparations and compost, raised carbon levels in sandy soils from almost 0% up to around 5%, which is quite high for a sandy soil. This is going to increase your nutrient and waterholding capacity of the soil. I think this was from a large commercial operation too, so it should be quite relevant. I'd say PurplePear could elaborate further.
     
  7. Tropical food forest

    Tropical food forest Junior Member

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    you can have too much organic matter
    and of the wrong sort

    I have seen some examples from peru of very fast land repair using leguminous trees
    this is on Acidic sands
    the buildup in organic matter is rapid
    however...theres a catch

    if you grow a crop of biomass like Inga or Acacia then you are sucking minerals out of the subsoil
    Studies under reforrested imperata grasslands saw a significant drop in subsoil base saturation (minerals like Ca and Mg)
    and a significant drop in pH (acidification)
    long term this is big trouble. esp if you keep exporting biomass as a farm

    ther are cases in Kalimantan of this. Acacia mangium plantations stalling after a few years as the soil becomes too acid to continue extracting nutrients. Acid soils also free up aluminium which is toxic to planst and aquatic life under acid conditions

    try and source ash or lime
    but not industrial sources
    for example coal ash is radioactive, and other industrial products are full of heavy metals

    there was a big fuss in WA a few years back as the red mud from bauxite was being used on the sandy coastal plain to improve soils. worked a treat!
    then its showed up that the alakline mud had liberal amounts of heavy metals
    oops! sorry
    now that land is permanently contaminated

    also you have to take BD with a grain of salt
    its not permaculture, its not organic agriculture, its not a science
    its a religion
    if you are ok with that then its nice to be part of a club
    and for the time being you can get a premium on your produce
     
  8. Tropical food forest

    Tropical food forest Junior Member

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    heres a paper on the Acacia mangium

    https://aboutcogongrass.org/pubs/cg_yamashitan2008p362.pdf

    its worth considering
    if we try to hold systems in their early nitrogen intensive state for too long
    then we will acidify the soils, unless we add outside sources (Beach shells, fossil coral, mined deposits)

    they need to proceed once the nitrogen is restored to a later state where non legumes dominate
    theres not enough research on later states done yet
    but its starting, looking at trees that go deep and pump minerals back to the surface

    in a temperate system you might think of these like oaks which accumulatef calcium
    or in the tropics there are planst used in the amazon to make ash/lime for snuffs and pastes
    (Coca. yopo, epena, tobacco etc)
    planst that create a high grade lime are selected and in teh case of the Coca the consumption adds minerals to a diet that is otherwise poor from the leached rainforest soils

    some of these are chocolate relatives. using the bark or husks
    Cacao has 2 forms of roots, some are surface and others go deep. Its been suggested these deep roots are for pulling up minerals

    Sterculiaceae (Chocolate and kurrajong family)
    and Lecythideae (brasil nut family)
    are often reprsented in ash source lists
     
  9. matto

    matto Junior Member

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    "You don't have to believe in it for it to work"
    I believe it is as much a permaculture tool as Natural Sequence Farming or Keyline design.
    Its also rigorously tested.
     
  10. Tropical food forest

    Tropical food forest Junior Member

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    the good from bauxite tailings

    https://www.publish.csiro.au/paper/SR9890651.htm

    re the heavy metals in bauxite tailings
    i may have made an error

    however there was problems emerging when i left WA year back
    i remember they hype because i thought it was a great idea - it is in theory
    adding clay to sands
    but there was a side affect that got everyone upset ...some kind of contamination
    if i can find what it was ill post it
    it may just have been the salt content
     
  11. Tropical food forest

    Tropical food forest Junior Member

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    heres a good start anyway

    https://www.redmud.org/home.html

    https://www.redmud.org/Characteristics.html

    Up here theres another industrial product from sugar cane
    Mill mud

    its good stuff. it has the C:N ratio of a good finished compost
    and lots of nutrients
    https://www-sugar.jcu.edu.au/images/publications/Occasional/Mill Mud Case Study in Mackay.pdf

    it might also have too much cadmium to use long term
    -almost any high P source does
    but id still use it to re-establish a degraded site as a one off
    If you have Cane processing locally then look into it
     
  12. Tropical food forest

    Tropical food forest Junior Member

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    no but it should work for you to believe in it

    show me the rigorous testing

    all i find is grey literature in support
    the published peer reviewed data says there is no effect that isnt attributable to non biodynamic organic methods

    https://soil.scijournals.org/cgi/content/abstract/64/5/1651
    https://cel.isiknowledge.com/full_r...ds&qid=2&[email protected]&page=1&doc=4
    https://cel.isiknowledge.com/full_r...ds&qid=2&[email protected]&page=1&doc=2
    https://cel.isiknowledge.com/full_r...ds&qid=2&[email protected]&page=1&doc=9
    https://cel.isiknowledge.com/full_r...s&qid=2&[email protected]&page=2&doc=11
    https://cel.isiknowledge.com/full_r...s&qid=2&[email protected]&page=2&doc=18

    i find the evidence scarce. theres a definite pro for organic inputs, but BD consistently does not demonstrate additional effects worthy of the added layer of regulation. there may be something in the yields, with unknown cause, but theres cosnistently no effect on soils
    You can add it to the basket of cultural quirks that have a very interesting role to play in developing local agri-cultures, in the same way you might incorporate other elements of faith
    but its def not permaculure core principles material, and in good conscience id be keeping it well outside any PDC

    i buy mungalli creek milk
    but i still think BD is BS.
    ive visited the farm and seen the milking sheds and heard the production data from them
    they still get mastitis, its just they cant use antibiotics and the cow goes out of production till it gets better
    lucky they get a good price and have taken control of their own marketing
    im convinced the better taste is due to
    a) lower production per cow = lower stress
    b) Different breed of cow - they use the old breed with the creamier milk (someone jump in and tell me..used to be popular, big doe eyes, pale to tan coat, but is now superceded with the more watery high output black n white ones)
    and im happy topay more for them to keep making that milk
     
  13. matto

    matto Junior Member

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    I don't want to highjack this thread.
    I was told that Steiner insisted it be tested so maybe these paper are in German, and probably don't make the comparisons to organic practises, just that the hypothesis of Steiners statements be tested, and how the final product is affected.
    I know there has been some long trials done in Washington, Maria Thun has done alot of work with moon planting testing those planetary effects, and in India trials have been done for local application that do compare against non biodynamic organic production
    https://www.biodynamics.net.au/reso... ALTERNATIVE MATERIALS IN COW HORN MANURE.doc
     
  14. sindhooram

    sindhooram Junior Member

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    this may be a bit basic but I have really bad soil in my place. So I have been growing some things in containers on my roof. I mixed sand collected from near the beach (more of a sand than soil ) and mixed it with old cow dung and a bit of compost. lettuce, tomatoes, mizuma, and basil all flourished in the mix and produced fine - a respectable crop of tomatoes.
    I will grow more things next year after the rain..
     
  15. wenshidi

    wenshidi Junior Member

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    Thanks very much for the replies. They are all good for for thought. I have another site trip planned in few weeks time and then I will be able to proved more details of the soil type involved. Once I have that information I hope that we will be able to discuss some more.

    Chris
     
  16. Tropical food forest

    Tropical food forest Junior Member

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    sand is a great mix for drainage
    and tomatoes would tolerate the residual salt
    manure contains something that kills nematodes
    and compost is gold!

    keepup the good work!
    better be making the compost now!

    im not sure where you are
    but i read a paper on vermicomposting in india

    programs to regreen the streets now create a lot of flower and leaf waste that street sewwpers were buring
    a study determined that by mixing cow dung and street leaves
    composting then adding malay blue worms (Perionyx excavatus)
    a high grade compost was made

    neem leaf was the best
    Eucalyptus was high in phosphorus ( interesting for Australians )

    after that i started feeding neem leaf (lost of trees locally) to my worms and they love it
    also collected fallen flowers of albizzia lebbeck
    - they make a hot compost! hot as any manure can make!

    an avid composter will search far and wide for biomass
    when looking for manures, dont overlook leaf and flower drop of leguminous street trees.
    they can be very rich!
     

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