Soil testing

Discussion in 'Planting, growing, nurturing Plants' started by purplepear, Nov 28, 2009.

  1. pcereghino

    pcereghino Junior Member

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    Random thoughts

    Some random thoughts to add to the mix:

    Taking nutrients from the ocean is a good way to compensate for mineral leached soils. the minerals leached from our soils end up in the ocean. Shell provides calcium and micro-nutrients, seaweed for potassium and micro-nutrients. We have been dumping nutrients in our waters for so long, taking some back up onto land is probably a good thing.

    I think Sue is on target with her yelling about how you can't concentrate things that are not there - if you have old leached soils (read Australia) you may have to be more aware of nutrient deficiencies then those of us who live of young post glacial and volcanic soils.

    If you know about how climate affects your soils, and the nature of your parent materials, you may be able to get away with much less soil testing. However if you are going to put your family's health and/or livelihood in a soil, why not test it?! Nutrient deficiencies in soil lead to nutrient deficiencies in our bodies. That being said, I am confident enough in my nutrient collection and importation that I don't worry about testing.

    If you are trying to grow annual food crops in a cool climate, you may not get the early season nitrogen release you want for early greens from any old organic matter. Making compost with nitrogen release is a good trick. Not all organic matter is created equal. Spinich and mustard families are not terribly mycorrhizal, and so depend more on free nutrients. Animal sourced nitrogen (manure) solves this.

    We are surrounded by surplus imported nutrients (food waste). At least until the rest of society catches on, we have pretty easy access to all kinds of imported minerals through restaurant and home food scraps.

    Animals are natural nutrient accumulators. I treasure my chicken poop and my egg shells. They all go through a compost and into my intensive growing area, where soils are flecked white with egg chips, which makes me happy in our calcium poor humid temperate soils. Those egg chips we actually imported from calcium rich Canadian prairie where our only local source of bought organic chook feed is grown, as is the Phosphorus in the guano - but I suspect they get some from calcium rich bug shells.

    Keep your eye on phosphorus... most parent materials (rotten rock in which soils develop) are not naturally rich in Phosphorus. Atmospheric inputs are VERY slow. Bones are good source of accumulated P, I bury all my chicken bones. Only a few sources of extractable rock phosphorus are found on earth and will be increasingly hoarded by our corporate overlords. Lack of P on leached and damaged soils is very hard to solve without import--lots of people starving in the world for lack of phosphorus, and more to come.
     
  2. Ichsani

    Ichsani Junior Member

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    Sorry mate, I'm thinking 'not impressed'. There is some truth in your adage, but it is not a gem and does not shed much light on working with soil. Indeed it seems to refuse several other useful things to know about soil - which I simply cannot agree with.

    SueinWA sums up why pretty well - all I'd add is this... if you have made a significant investment in growing plants then a soil test is a small cost that will easily pay for itself. When it comes to recommendations about WHAT TO DO about what the soil test says THAT'S when you have choices where you can exercise your abilities to choose more sustainable options.

    I agree with you that soil tests are often overperscribed. I don't agree that they are particulary expensive considering the investments (time, money etc) involved in serious food production in well-off western countries such as Australia. As to are soil tests necessary? Not really if you haven't a 'problem' soil - in all other instances it'll save a lot of heartache.

    I'm happy to discuss about they key soil variables and options as best as I'm able if you like - maybe we should build a list for the forum.... a 'soil charter'... or something like that.

    Interested?

    You could amend the adage to 'no matter the question about soil, you can be sure the first answer is organic matter, the second and third answers depend'.... a little long but I hope you get my point

    Cheers
    Ichsani
     
  3. purplepear

    purplepear Junior Member

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    warm temperate - some frost - changing every year
    Sorry mate I've moved on - perhaps you should too.
     
  4. Ichsani

    Ichsani Junior Member

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    What a shame!
     
  5. ppp

    ppp Junior Member

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    I don't really think people who say "why test" are talking pH since it costs ~$10 for a kit
    what soil tests are pebble et al suggesting and how much do they cost.

    What would you suggest for someone who has recently bought 5 acres on residual silty sand soil overlying granite.
     
  6. Ichsani

    Ichsani Junior Member

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    Hi PPP,

    Firstly congratulations :)

    Here's a link to an Australian soil testing lab that has a pretty good reputation amongst organic growers etc. as far as I am aware
    https://www.swep.com.au/pages/home/home.html

    My next question would be 'what's your major plan?' ...i.e. If you're developing a food garden with the insitu soil then its prob a good idea to get an idea of the mineral soil that you're starting with (so that pretty much means a standard garden soil test with macro & micro nutrients but I would add total P to that). This means you can address deficiencies upfront and do some follow-up testing (if you like) after a few years.

    Also consider getting the topsoil and the subsoil done separately if you're planning lots of fruit & nut trees.

    With soil derived from granite it will typically need some micro & macro nutrient amendment to be a satisfying garden soil (especially B) - its usually used as grazing country because granite derived soil is relatively fragile (broadly speaking) that doesn't hold up to tillage well (but what soil really does in the long term?!).

    Essentially, the more intensive the extraction the more often the testing - the converse of this is that the more the system cycles its own nutrients the more often they get used (if they are there in the first place)... make sense?

    .....I agree it doesn't cost much to test pH, OM is great at buffering soil at around 6.5-7.5 pH once its there - actually moving pH there is another matter.

    Cheers
    Ichsani
     
  7. ppp

    ppp Junior Member

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    so we're talking a minimum of $126 or $385 for the "complete test"

    unfortunately, I'd say one test wouldn't be particularly representative.. from the extensive soil investigation program of conducted over the last 6 months (read planting out trees and vegies) I'd say I have at least four possibly three soil units so at least 4 tests.. one of the "hillside topsoil" one of the "creek topsoil" one of the "hill residual soil" and one of the sandy alluvium underlying the darker "creek topsoil".

    https://www.swep.com.au/pages/price/soil.html ??

    that's $500.. hmm I haven't added up the weight of the produce we've grown in the couple of months we've been here (from the diary), and we haven't really been trying, but I'm sure it would already top30kg.. things look relatively healthy.....
     
  8. Ichsani

    Ichsani Junior Member

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    Yep that price is about right. Mind you it does work out at about $5 per measure which is fairly good value (except that its a package). I personally wouldn't do the 'complete test'... I do think biology is vitally important but testing for it is another matter... But if you think that testing won't yield much benefit to you compared to the efforts put in then its a bit of a no-brainer.

    Me, I don't think its very expensive but then I also hold the info that tests can give generally in high regard, because its pretty hard to get that info any other way and I spend most of my time thinking about such things- having said that, you're already on the way towards knowing more about the whole of your soil than anyone else.... digging around is the best way to get to know the types of information that testing can't give you (colours, types, where the water flows, depth etc)

    One sample isn't very representative, you are correct. To get around this you make a composite of the particular soil area you're testing - the same amount of soil from the same depth for several places in your area, mix it thoroughly in a bucket and extract a sample to be tested - giving you an average of all the spots you extracted from. Might be a useful technique at some point.

    Else, there's always a container or two of 'trace elements' from the garden store... I use this when I know the soil isn't much chop in this regard but testing isn't warranted (ie too small).... it really is a investment/risk decision etc

    Anyway - sounds like things are doing great guns

    Cheers
    Ichsani
     
  9. ppp

    ppp Junior Member

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    I'm searching for literature on my soils.. there is /was an agricultural research area very close by, I can only find stuff on low nitrogen so far. I beleive the granite unit I sit on is fairly extensive, so I expect the soils to be similar
     

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