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Post by mnjrutherford on Jul 26, 2009 7:35:04 GMT -5
I think you are on to something regarding the terra preta Patrick. I think it's highly doubtful that they thought of it as anything more than a garbage pit that required proper tending to keep from being a nuisance bug and smellwise.
Because everything was in there, you had maximum diversity. Max in, max out...
What I'm unclear on though, is how did the fire/heat effect the NPK content? Did it just make the nutrients easier to access?
We still have our pit going but it has tons of flys. Not all the flys are of our own making, we have hog lagoons less than a mile away. I just found this out a couple months ago. I try not to think about it to much...
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Post by paquebot on Jul 26, 2009 21:59:57 GMT -5
That is correct. Once P & K are removed from the soil, it must be moved from elsewhere before it can be returned. No plant can produce it on its own.
Yes, every non-parasitic plant relies upon NPK for growth.
See previous quoted statement. The need for NPK has been known for as long as Man has been tilling the land and planting things. He may not have known what it was but knew that he wasn't going to get any food back for his efforts unless there was fertilizer in the soil.
That is only possible if nothing is ever removed. Every blade of grass or leaf contains a certain amount of NPK. The natural way is for them to fall to the ground and degrade in place to keep the status quo. If removed from the area, that amount is gone and the percentage of NPK in the soil is that much lower. If "green" organic fertilizer is employed to replace it, the source must suffer according to Nature. If from a terrestrial source, land elsewhere must suffer. If marine, than the sea must suffer the loss.
Same as pre-fertilizer company days. They didn't know what P & K was but knew that their own ashes supplied something that their crops needed. Those people had no cemeteries! Had they had a better understanding of how many people the system could support, their civilizations would still be going strong. As good as many claim that it was, it still failed. They ran out of people!
Martin
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Post by grunt on Jul 26, 2009 23:50:01 GMT -5
Not really trying to pick nits here Martin, but the reason they failed was massive outbreaks of disease caused by the contact with the Spanish. I agree that closed system agriculture only works if nothing is removed from the system. Patrick, if you look at any past agricultural society to use it as an example, you cannot look at a single farm/growing unit in the same way. The society as a whole is the unit from which nothing is taken, provided there are no exports. A single farm/growing unit that moves nothing out of the system is almost impossible, and is bound to degrade over time. On the human scale of viewing time, it may indeed seem to be sustainable, but in the long run it is the same as entropy, a one way movement of energy. Anything that is removed from the system, even if it is only the bodies of the farmers, results in fewer resources being available to the system, which over time cannot help but degrade the system. In the world of physics, which rules the world of gardening, there are no free rides. Robert Heinlen introduced a phrase in The Moon is a Harsh Mistress, that applies here "TANSTAAFL" -There Aint No Such Thing As A Free Lunch. If you eat the produce from the garden, you have to replace all of it, including that which your body has converted to energy to allow you to work in the garden. If you do everything else right, the degradation of the system will not be enough for you to notice in any normal human time frame, but using a more cosmic time frame is a different matter. If you transpose the matter of the farm/growing unit into energy (physics says they are equivalents) it becomes much clearer, the removal of any portion of the unit results in a diminishing of the unit = entropy is.  |
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Post by PatrickW on Jul 27, 2009 8:59:08 GMT -5
Jo: You're right, the fire won't change the NPK content, but like you said the potassium in wood ash is very available, and not the best thing to put a lot of directly on your garden.
Martin and Dan: The thing is we live here on planet earth, and it's one big ecosystem. NP&K are never destroyed, they just change form and move around. In modern society, we are so into producing and transporting. We like things like running water coming into our house and sewage running out, which cause all kinds of natural imbalances, but the basic elements are never destroyed. Nature can often compensate for these imbalances, but it's of course always better to work with nature than against.
If you're an ordinary gardener, and sensibly manage your inputs and outputs, once you have a stable system you don't need to worry about NPK imbalances. This is because the loss of P & K will be so slow, that it's not likely to be important in your lifetime, and there will be some natural systems reintroducing it into your garden anyway. You can garden in this way without soil amendments. Even composting is unnecessary, as you can do what I frequently do and just put weeds and other waste directly back into your garden beds where they act as mulch until they decompose.
There's no way of knowing for sure if the terra preta people knew what they were doing, but even if they did use the black earth they created as a soil amendment, there no reason they would have needed to. They were creating some of the richest land the world has ever seen, and if they just abandoned their waste pits natural forces like flooding of the rainforest would have spread them around.
When the time comes you realize you have a problem with a loss of P & K, while soil amendments are one way to deal with it, there are natural ways too. Like I mentioned before, attracting wildlife that would do it for you or encouraging flooding or whatever. It's not like the ground is hurt in any way by this.
It's just not necessary for the average gardener to concern themselves with NPK, except at the beginning to identify pre-existing problems as well as to understand the basic natural mechanisms surrounding them well enough to track down problems when they exist.
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Post by silverseeds on Jul 27, 2009 10:03:39 GMT -5
I am going to try this terra preta concept on a bed of mine, I think it has amazing properties, and seems to solve many issues, my soil has. Anyone know a good source on info on how to do it?
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Post by PatrickW on Jul 27, 2009 11:23:44 GMT -5
I am going to try this terra preta concept on a bed of mine, I think it has amazing properties, and seems to solve many issues, my soil has. Anyone know a good source on info on how to do it? Yes, Alan. If you look in the Soil Building section, there were some very long discussions on the subject. |
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Post by mnjrutherford on Jul 28, 2009 17:51:03 GMT -5
Yea Zac, a HUGE thread on the subject. I've posted photos of our own project currently underway. If you search on the forum for Terra Preta and go back to March time frame you should find it. Meanwhile, I'll try to find the link for you...
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Post by mnjrutherford on Jul 28, 2009 17:55:04 GMT -5
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Post by silverseeds on Jul 28, 2009 18:20:47 GMT -5
Thanks for the link, I am going to try it I think for one bed and see what happens.
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Post by bunkie on Jul 29, 2009 8:51:07 GMT -5
Yea Zac, a HUGE thread on the subject. I've posted photos of our own project currently underway. If you search on the forum for Terra Preta and go back to March time frame you should find it. Meanwhile, I'll try to find the link for you... jo, i can't find your photos? have you a link for them? and how does one keep an open pit going during the fire season? i know here, they ban all burning, campfires, etc... during that high fire danger season. |
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Post by mnjrutherford on Jul 29, 2009 11:43:52 GMT -5
trulythankful.typepad.com/photos/terra_preta_pit_project/index.htmlThat link will take you to the first album dedicated to the project on my blog. There are a few more photos in the dated albums posted later. I have to laugh about your question regarding keeping it lit for several reasons. First, we came from California. Back home you had troubles lighting a match let alone a fire! When we came here, we were told that the best way to get rid of massive trash piles was to burn and to go get a permit at the store down the road. Naturally, we kinda figured we were getting our legs pulled. Regardless, we went to the store. At the store, there's a little sign by the door reading "Burn Permits" and it had the logo of the state forestry service. OK, well, guess our legs weren't being pulled to hard. Went in, asked for the permit, we were given a ledger book to fill in (the permit is free by the by) and we nearly passed out laughing when we had to answer "How many acres will you be burning?" The drought has changed that a LITTLE, but not here on the coast. The other thing that makes me laugh is that despite our best efforts, the darn thing goes out after a couple days.  So, when the collection is "noticeable" or a lot of green (weeds, trimmings, grass clippings, etc.) goes in, then we light it and let it cook down. Not what we had in mind, but then that's part of research. Right? 
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Post by pattyp on Jul 30, 2009 13:57:47 GMT -5
Hi everyone. I really appreciate all of the comments that I have received on this thread. The science teacher in me wanted to weigh in with one observation about the physics that have been employed in the discussion. Grunt said: The law of entropy applies to closed or isolated systems, but our gardens aren't really closed systems in terms of energy because the sun inputs a huge amount daily. The same could be said for lightning in that it fixes nitrogen into a usable form for plants (although I'm not certain how many of us have experienced lightning strikes in our gardens ). However, raindrops also contribute to inorganic nitrogen in the soil, which can then be fixed by bacteria. So I'm not certain how useful it is to apply the law of entropy in this case - although I love the addition of Heinlein to the discussion  . Patty |
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Post by Alan on Jul 30, 2009 15:23:04 GMT -5
Wonderful and valid points pattyp, atmospheric nitrogen is trapped within rain and "zapped" by lightening as well! Something we probably all knew but hadn't thought of in this thread, thank you for bringing that up my friend!
-Alan
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Post by silverseeds on Jul 30, 2009 17:54:22 GMT -5
The natives americans of this area used that idea well. They would often use an area for a couple years, then abandon it for up to 10 or 15 years, waiting for the atmospheric nitrogen whether they knew it or not. I also think trees add to this, bringing up things from very deep levels of the soil.
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Post by paquebot on Aug 2, 2009 21:42:35 GMT -5
The natives americans of this area used that idea well. They would often use an area for a couple years, then abandon it for up to 10 or 15 years, waiting for the atmospheric nitrogen whether they knew it or not. I also think trees add to this, bringing up things from very deep levels of the soil. I've never seen any credible mention of native Americans doing that. The opposite was generally true with them long ago having learned the importance of fertilizer. They are famous for getting great harvests year after year by using fish for fertilizer. Many southern tribes had huge permanent fields already before European settlement. They didn't know what NPK was but knew that fish and their own manure was great for growing food. Trees can bring up elements only if they exist in the soils. Each variety of tree grows naturally in soil having the elements which are needed for it. Many trees have adapted to having their leaves remain close to where they fall. Most of the elements contained in them is thus recycled back into the soil within the root feeding zone. Others are more efficient and have leaves which are easily blown away. It's almost as if the tree knows that there is an excess that they don't need. Where I garden, it is impossible to even think of waiting for a single ounce of phosphorus or potassium to renew itself. The soil is split almost 50-50 between alluvial and airborne silt. The alluvial half came from Canada via a glacier 10,000 or so years ago. The airborne half came from Nebraska and Iowa over the 10,000 or so years since. It was grassy prairie for good reason, there were no sources of phosphorus or potassium within reach of any roots. Were it not for thousands of years of bison grazing and dying, there would have been even less than the minimal phosphorus existing today. Potassium is merely a trace despite there being an excess 60-70 miles south of here. Before farm fertilizers were available in blends specific for a certain field, the generic corn formula for this area was 5-10-30. The northern portion of Illinois needed 6-24-12. The soils in both areas were the result of the last Ice Age. I don't think that Man can sit around and wait for another to replenish it! Martin |
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So, when the collection is "noticeable" or a lot of green (weeds, trimmings, grass clippings, etc.) goes in, then we light it and let it cook down. Not what we had in mind, but then that's part of research. Right? 
.
