A significant goal for my site has been to amass reliable information for myself, and therefore, my readers. The information I place on this site has been extensively researched before it is posted. As a physician (M.D.), I strive for scientific accuracy. I am well-versed in the scientific method and critical reading of scientific research articles. I understand the world of academia. I know, beyond doubt, the benefit this arena has provided for the world. However, I also know, beyond doubt, that there is a lot of truth that has not been proven in a lab. This may be due to many factors. To name but a few: the topic has not yet been studied, there are flaws in the design of the study, the topic is too complex for reductionist evaluation.
It is with this mindset that I readdress the concept of Dynamic Accumulators.
Within the world of Permaculture we often find reference to plants known as Dynamic Accumulators. I wrote about these plants in a previous article, but in brief, it is the idea that certain plants (often deep-rooted ones) will draw up nutrients from the lower layers of the soil, and these nutrients will be deposited in the plants’ leaves. When the leaves fall in autumn and winter and are broken down, those stored nutrients are then incorporated into the upper layers of the soil where other plants will benefit from their deposition.
Comfrey is one of the most popular Dynamic Accumulators.
So, with our scientific minds turned on, does the concept of Dynamic Accumulators hold merit?
In short, my answer is a non-comital “maybe”.
Let’s start with the scientific evidence… well, there is not much. In fact, I can find almost no research into Dynamic Accumulators. Strike that – I can find NO research into this concept at all. None. Many sources site references, but these references just don’t pan out. There are circular references, there are references to non-existing sources, and there are references to (just being honest) less than reputable books or authors. I have to be very fair and state that I am not the utmost scientific-research-article-searcher in the world, but I am pretty darn good, and my lack of results was a bit disappointing.
As it turns out, it appears that the concept of Dynamic Accumulators has been passed down and around for so long that it has been accepted as fact. This concept did not originate with Permaculture, but it has been adopted and advocated by it for a long time. So much so, that many people associate Dynamic Accumulators with Permaculture.
Chickweed is another popular Dynamic Accumulator with many additional benefits.
Well then, how did this concept get started? Where did it originate? Is there any proof at all?
This is where I back away from the cliff a bit. We do have evidence that some plants accumulate minerals in high concentrations in their tissues. This concept has been significantly researched. In the botanical community, this concept is known as Phytoaccumulation or Hyperaccumulation. There are a number of hyperaccumulator plants that can grow in soils with high concentrations of certain minerals, often metals. These plants can be grown in areas that have been contaminated with heavy metals or high-value metals. The plants pull out these minerals (phytoextract) from the soil. The plants are then harvested and processed to extract the minerals from plants to be recycled or dealt with in a more ecological manner. This “phyomining” has been used, with success, on significantly contaminated sites.
In addition, there has been an extensive database put together by botanist James “Jim” A. Duke Ph.D which provides information on thousands of plants. Specifically, and for our purposes, the database provides information on concentration of minerals found in the tissues of plants. His Phytochemical and Ethnobotanical Database is hosted on the USDA ARS site (that is the United States Department of Agriculture, Agriculture Research Service). This is a wealth of information that would take a long, long time to fully peruse and appreciate. Using the information from Dr. Duke’s database, a free, downloadable Nutrient Content Spreadsheet was created. I am not sure who created it, but I found it on Build-A-Soil.com. This is well organized spreadsheet with multiple worksheets (pages).
Lambsquarter (Chenopodium album)
With this information we can connect the dots for Dynamic Accumulators. For instance, we can see phosphorus (P) concentration in Lambsquarter (Chenopodium album) is over 36,000 ppm (parts per million). This is a high concentration. Therefore, it would make sense to grow Lambsquarter on our site, let the Lambsquarter die back in the Autumn to be composted in place, and then have higher concentrations of phosphorus (P) in the Spring.
Unfortunately, while this scenario sounds good, we have no proof that it will work. Our logical pathway sounds plausible, but the reality is that Nature is never quite so simple as we would like. Minerals don’t appear out of nowhere (alchemy is still not a science!); if the soil has no phosphorus, then the Lambsquarter cannot accumulate it. If the soil has no biology, i.e. Dr. Elaine Ingham’s Soil Food Web, then there is a good chance the phosphorus may not be bioavailable to the roots. And while our scenario sounds good, we have no scientific proof (research data) that if the Lamsquarter did accumulate phosphorus it would indeed be returned to the soil in a usable form to future plants. Maybe it will, but would it take 1 year, 5 years, 25 years to become available again? This is information that we just do not have.
People will often swear by their Dynamic Accumulators. They will site their own garden as “proof”. Unfortunately, this is anecdotal information and not scientific evidence. I am not saying that their soils did not improve with the planting of Dynamic Accumulators, but was it the dynamic accumulation or another factor that caused the improvements such as mulching, composting in place, biomass accumulation, biodiversity, microclimate creation/enhancement, etc. As a good friend of mine likes to say, “The plural of anecdote is not data.”
What then should we do with the concept of Dynamic Accumulators? Take the information for what it is, soft data. That is, we can make some logical assumptions, i.e. “guesses”, and hope for the best. But we should not treat or teach the concept, the theory, of Dynamic Accumulators as scientifically proven information. We should not treat it as fact. We should definitely not rely solely on dynamic accumulation as our single solution for degraded soils. Of course, if we are appropriately applying and practicing Permaculture, we wouldn’t do this anyway.
Personally, I will continue to use Dynamic Accumulators in a holistic approach to soil improvement. It may help our soils for our intended purposes. It may help for entirely another reason. And having more diversity on our sites will almost always be of benefit… scientifically proven or not.
Note: If anyone has come across published research (not books and not anecdotes) on Dynamic Accumulators, please send me a link!
*SECOND NOTE: Due to some great input and conversation on this topic both here and on my Facebook page, I updated this article. It was published on the Permaculture Research Institute’s page here.
Photo References:
- http://lh6.ggpht.com/_ofF5B1eh_dM/SxPeCIYqJNI/AAAAAAAAITE/_azGECDUfi0/Symphytum%20officinallis.jpg
- http://luirig.altervista.org/cpm/albums/bot-045/stellaria-media268.jpg
- http://ca.wikipedia.org/wiki/Blet_blanc#mediaviewer/File:ChenopodiumAlbum001.JPG
Excellent article on Dynamic Accumulators. Is it possible to somehow easily determine for example, soil levels of phosphorus prior to planting an accumulator plant such as lambsquarter, and after dieback over subsequent years to see if any changes take place? As you mentioned, I feel it would be advisable to do this in an area of your property where you are not amending the soil via compost, mulch, etc. Also, how can we measure phosphorus or calcium levels in the plant tissue itself without having to pay a chemist? Is there a DIY method for the average Joe?
My HMI teachers, who have studied with Elaine Ingham and Betsy Ross, say that the commercial tests are worth it. They recommend the basic test at Logan Labs, though everyone has a favorite. FWIW.
Thank you for this excellent site. Have you seen Robert Tate’s excellent book Soil Microbiology?
Besides the data, there are explanations of his methods and procedures.
Soil Microbiology, Second Edition
Robert L. Tate III, Rutgers University
John Wiley & Sons, Inc 2000
excellent aproach to the subject, thank you for aplying high standards to this, we need to do exactly that.
Greetings from Argentina
Hi kury!
I’m a novice permaculturist from Argentina! I’d love to contact you if posible.
Thank you for this. There are lots of so called truisms within horticulture that are promulgated that dont appear to have any scientific basis. I understood that Comfrey is deep rooted so would probably harvest minerals at a greater depth than average plants. It probably is fine as part of a mulch and/or in the compost. But the transfer of minerals in a form that microorganisms can convert to forms that can be plant absorbed is not proven?
There are other folk lore type beliefs. I was told that pine needles are too acidic for mulch purposes and that the resin will act as a growth inhibitor and will not allow other species of plants/trees to germinate in the pine needle bed. Well I have evidence of rampant native evergreen seedlings/growing up through what must be an average 100-200 mm of pine needles. I have used pine needle mulch for 2 years now with no detectable ill effects. I then found a site in California that markets pine needles and had a pdf file on some tests they ran on ph of pine needles in solution etc. their evidence was that the pine needle compost was no more acidic than rain water.
There are strip test kits available. Part of my Soil Health classes at UW-Madison.
https://www.youtube.com/watch?v=Onvue39-lvY
Thank you for this post! I didn’t know that this was dynamic accumulation was even possibility.
In regard to its validity: ask the plant! … They will tell you, unequivocally. Science will find out what they know about themselves given time.
If science is where your sole faith lies, then, well, I’m stumped.
References for the concept of plants communicating their uses to humans: Sacred Plant Medicine by Stephen Harrod Buhner; The Cosmic Serpent by Jeremy Narby, Anthropologist
See the conversation about this same topic in the forum at Geoff Lawton’s site. They discuss proof vs dogma of the dynamic accumulators reasoning. http://www.geofflawton.com
Andrea, please give a more specific link to the topic. Thank you!
Thanks John. It is so good to see such a clear assessment of the science or lack of it in relation to long-held myths. I will continue to use Dynamic Accumulators (so-called) if I see that they are having a beneficial effect on my soil, I just won’t be using the term dynamic accumulator or suggesting that this is their role. Science-based permaculture. Yes!
I am not sure who created it, but I found it on Build-A-Soil.com. This is well organized spreadsheet with multiple worksheets (pages).
http://portageperennials.wordpress.com/?s=dynamic+accumulators
Sounds like an opportunity for us permaculturalists to do some citizen science. I’ll be setting aside a test plot or plots.
Well writen blog post. A good read. A refreshingly structured approach to the topic.
Hi John, I’ve been reading your blog for ages, and this is the first time I’ve really needed to drop a comment. I think what you’re doing with this post is incredibly important, and it’s something I’m intending to do with my own permaculture projects as well. I think that Permaculture badly needs open-minded skeptics and quantifiers, becuase while there is a lot of great information, there’s also a lot of stuff that’s either misunderstood or overstated.
I have 20 acres that I’m using to put many of the claims of permaculture to a controlled experimental test, but it’s a slow process. I think that by bringing people’s attention to these issues, you’re probably going to inspire people to question some of the dogma and put it to the test, and as a result permaculture will lose some myths and gain some facts, and ultimately become a much more powerful force for changing the world. Great work!
Thank you for doing the work to analyze this issue. As someone pretty new to pemaculture concepts (but not to herbal medicine), I find it difficult to separate the hopeful from the logical … I also appreciated the comment about pine needles and acidity; I’ve been rejecting pine straw as mulch because my sandy soil is already acidic but it’s good to know that I might be able to make use of this very available, reasonably priced resource.
Thank you again for your work and your communicating the results to us!
Hello John,
Great approach to blogging information. I also strive for scientific evidence.
As soon as I heard about “dynamic accumulators” I felt the urge to investigate for evidence. I remember looking first for evidence about the accumulation of the stated nutrients for each plant and finding what seemed sufficient reliable data to confirm it. Than I looked into proof of release of these nutrients and reading papers about the release of N from leguminous plants or about nutrients from tree fallen leaves for example in agro-forestry inter cropping studies or forestry (there’s seem to be some published information on this) I assumed the reasoning was sufficiently sound. I still miss quantitative and specific information for each plant.
There are a lot publications on decaying of organic matter and nutrient release and cycling.
I believe the information is there but not as straightforwardly as we would like to read it. Anyway, any update on this post will be highly appreciated!
Robert Kourik’s book “Designing and Maintaining Your Edible Landscape” is the first major source of information on dynamic accumulators, and the table of them that is reproduced all over the web is from that book. I meet with Robert regularly, and he says he regrets ever having published that table. I’m in agreement with John that the research is largely lacking and is mostly anecdotal or folklore. Robert is now in the process of doing lab analyses and a deep literature search to find hard data on accumulators. We do know from hyper-accumulators that there are plants that specifically uptake certain nutrients, so there probably really are “dynamic accumulators,” but we’re a ways from knowing truly what they are. The table in my book “Gaia’s Garden” was taken in part from Robert’s, and part from some papers on hyper-accumulators (which are now lost due to a hard drive crash). I will almost certainly omit that table in the next edition of GG, and just have a general note about accumulators.
Thanks for the useful post.
That is awesome, please keep us updated on Robert’s findings!
John, I liked what you said, in your 8th paragraph. It starts,”Unfortunately, while this scenerio sounds good,”. The point was made, ” if the mineral is not there, in the soil to begin with, then It will not , at any time, be in the plant!”. It will not take part in any process necessary to produce vitamins or chemicals that plant is capable of making. So, it makes no difference if concept of Dynamic Acummulators holds merit or not. Of course logic, my own common sense and research tells me it does.
This is 2015 we are able to build a perfect root growing inviroment with the exact mineral content that we choose,,, in a form that causes the mineral to be USABLE NOW! We can also control the PH, moisture/ drainage, texture and temperature, as well as lighting.
With the advancements modern space age technology, tools for plastics and other materials, Three-d printing and other forms of manufacturing. We are right around the corner from an 21st century evolution in how we ( personally) will grow our own food. Good article friend.
Dynamic accumulators? Every plant is an accumulator. Water, carbon, minerals – most plant nutrients occur at higher concentrations in the plant than in the soil. The ability to gather minerals from less accessible portions of the soil, and having the vigor to do it when other plants fail, seem like the only interesting points. For example, aggressive roots that can penetrate compacted layers, deep taproots that can exploit otherwise unused portions of the soil, adaptability to fluctuating moisture regimes (drought or flood), etc. The ability to quickly absorb nutrients like nitrogen from the soil is typical of any fast-growing plant – not very unique. But the ability to cover the ground and enrich the soil in conditions so adverse that they would leave typical crops with little or no harvest, that’s a valuable quality. And if it can do this without being invasive, it’s a winner.
Well said Brian. I try to chop and drop with a lot of different plant materials and comfrey is in that mix. I remain deeply impressed with the impact that chop and drop has on the soil. I’ll leave the science to other people and keep doing what I’m doing. As I read through this article, I kept thinking about the property that used to be the Permaculture Institute up near Mt Warning, which is now an extraordinary forest for foragers. If the end result is a garden of Eden and comfrey was part of that process then this is something that cannot be ignored. I do get it about extraordinary claims though.
Great to see someone digging into the murky world of Permaculture “sacred cows” !
On the subject of dynamic accumulators (such as Comfrey) has anyone seen a report into their effect on livestock?
My concern is having plants such as comfrey available as feed given the high levels of pyrrolizidine alkaloids which I understand are toxic to many animals (eg. horses,cows) and detrimental to others (such as sheep and goats which I understand are better able to tolerate them).
A excellent podcast on comfrey. It will answer a lot of questions on comfrey. http://www.thesurvivalpodcast.com/episode-1371-all-about-comfrey-the-miracle-plant
I heard one guy say he was cutting some comfrey to feed to his goats for the B12 for their milk. Made sense to me.
What about research into prairie grasses? I know they have done a lot of research into their greater drought resistance, maybe some mineral profiles were also done? It would be from different or non-native plants in the same area so might be a good comparison.
Contemporary science does take a whole approach to anything…it compartmentalizes and seeks the answer to specifics as the article author shows. If there is no paper on it then the odds are it is anecdotal and cannot be true right up a paper is produced which makes a claim one way or the other.
Instead of seeking papers people need spend time with the plants growing on the land through one and if possible two full growing seasons and record everything no matter how seemingly common or unimportant. They don’t need science to grow where they do. They simply need the right conditions for them to flourish and as the commenter up away’s said all plants are bio accumulators…the term itself needs composting not verifying with a scientific paper.
Your articles are wonderful! Thank you so much for your time and effort in collecting this valuable information!
Ben Stallings wrote an article on the PRI website showing before and after soil test results on soil under comfrey plants after 5 years. That does show quantifiable data on nutrient levels for one specific dynamic accumulator on one site, but that isn’t the large-scale study you are looking for, if I understand you correctly. Here is the article for what it’s worth: http://permaculturenews.org/2014/03/18/comfrey-really-improve-soil/
John, I feel like you hit the nail on the head with this comment: ” if the soil has no phosphorus, then the Lambsquarter cannot accumulate it”. This has always bothered me about the mineral accumulator talk. I like the idea and feel it could work but……if the minerals aren’t there, they can’t be accumulated. Like you though, I will still plant them as part of my overall system. Thanks so much for your work.
Interesting topic John and I agree there is not enough research done, but I have found a few interesting articles in google scholar that might be related, here is research done to capture toxins and heavy metals with the help of plants as I have been involved with in Germany in the early 80’s in so-called brown-fields. We used annuals to pull out heavy metals like zinc, cadmium, and lead. They where harvested and tested and stored at a hazardous waste site, interestingly I got into a bit of trouble one year as I had surplus compost dumped on half a field and when they tested the plants the next year they found no to very low concentrations of metal, turned out that compost was fixing the heavy metals into the soil.
http://pubs.acs.org/doi/abs/10.1021/es903921t?journalCode=esthag
Herb – yes, this is the “hyperaccumulation” I was referring to. The information about the compost is really interesting. This reminds me of the salt being trapped in Geoff Lawton’s “Greening the Desert”.
John
Very good article John. I whole heartedly believe we need scientific backed research to inform permaculture techniques and principles at the academic level and in teaching permaculture, I hate to see permaculture ride down the road of purely reductionist science. Planting a diversity of plants with variety of root depths in a polyculture works. Dynamic accumulators is a good theory and makes lots of common sense, like a lot of other unscientifically proven methods in permaculture and farming; like say, designing from natural patterns to the details; we just assume it is a better way than mono cultures but do we know for sure how it works? I am not sure that we don’t also not know just how minerals and nutrients come to be in the soil as biochemistry tells us that things change in living systems and atomic structures migrate; like uranium decaying to lead. I learned about soils that if I get the biology right the chemistry would follow as it has in natural systems. I love your site and read it regularly. You are doing amazing work.
Thanks John. It is good to have proper evidence on this topic also. When using plants as Dynamic Accumulators there is one other plant feature valid to pay attention. Many plant species produce and release chemicals that are toxic to other plants, a phenomenon referred to as alleopathy. (http://en.wikipedia.org/wiki/Allelopathy). Plants allelochemicals can also have positive effects in many cases as you have described on your website for some plants (black locust, buckweat, pine tree).
e.g lamsquarters (Chenopodium album) aqueous extracts looks like to be toxic at least for lettuce, tomatoes and onions. Most probably they are toxic for many other plants.
( http://seas.iung.pulawy.pl/pdf/str102.pdf).
On the other hand when we are talking about plant toxity it is always relative concept. Even water is toxic if we drink it too much.
I really like your site!
information about comfrey being a bio/dynamic accumulator with test results. http://permaculturenews.org/2014/03/18/comfrey-really-improve-soil/
Weeds
Guardians of the Soil
by
Joseph A. Cocannouer .This is not exactly science but practice that explain the benefits from weeds..
http://journeytoforever.org/farm_library/weeds/WeedsToC.html
Great stuff,
If you haven’t come across Steve Solomon and his work at Soil and Health library already then I recommend it.
Hey John, great post here. I really appreciate your balance of science and common sense. It’s a refreshing to see someone with a scientific background being open to the possibility of something functioning without seeing hard data. That said, we would all love to see more studies to support the viability of Permaculture techniques.
It comes down to the fact that true scientific research is very costly and time consuming (you have to wait for stuff to grow and develop with natural systems). I hope that over time our movement will amass enough resources to test the theories. However, if we ever find that dynamic accumulators don’t actually work, I’m still going to love Comfrey as much as any other permie 🙂
The use of comfrey, I thought, developed from the work of Lawrence Hills and Henry Doubleday and the charity The Henry Doubleday Research Association now called Garden Organic.
I have been using comfrey for over forty years and only recently heard the term dynamic accumulator. I don’t understand the term because plants are not very dynamic and all plants accumulate nutrients.
Lots of plants can be used in a similar way to comfrey. Ken Thompson in his little book “An Ear to the Ground” suggests Stellaria media, Urtica dioica, Chenopodium album, Galium aparine and Alliaria petiolata.
I use a mixture of wild comfrey, nettle and sweet cicely to make a liquid fertiliser which seems to grow tomatoes particularly well.
I haven’t read all the comments but you might find this useful and might give you some avenues to find useful links. https://www.youtube.com/watch?v=CTcCxn4WXFc
As mentioned in earlier comments, plants can only accumulate minerals if they are in the soil. Plants can’t manufacture minerals. The facts clearly show that not all soils are created equal. This can be seen on the USGS site that shows the mineral makeup of different regions of the country. http://mrdata.usgs.gov/soilgeochemistry/#/detail/element/15
Different plants use and accumulate different amounts depending on the physiological requirements. If plants are sampled the younger tissue will have higher amounts than older tissue. There have been a number of studies showing that the same vegetables grown in different regions of the country accumulate differing amounts of minerals. Bear, F.E., S.J. Toth, and A.J. Prince 1948. Variation in mineral composition of vegetables. Soil Sci. Soc. Am. Proc. 13:380-384. Beeson, Kenneth C. The mineral composition of crops, with particular reference to the soil on which they were grown. U.S.D.A. Misc. Pub. No. 369, 1941
What we all have to understand is that there are so many variables that have to be considered. Things like soil composition ( clay, sand, organic matter ), mineral composition (17 essential minerals and how they are balanced ), environment, the requirements of the plants being grown are just a few. Always do a soil test and continue to test as you improve the soil to make sure you are providing the balance that is needed to achieve optimum growth and yield. And depending on what part of the country you live in you may need to add missing minerals.
The small acreage that I live on has 5 different soil types and each takes a slightly different approach in order to maximize results.
As everyone has already said, this article makes an excellent point — that we shouldn’t confuse folk wisdom and logical assumptions with scientific data or proof. And by saying this, we do not have to downplay the value or validity of such “unscientific” methods. Both have their usefulness and belong in our toolbelts, and I am not in favor of enshrining the scientific method as the supreme and exclusive authority. I particularly appreciated this statement: “I also know, beyond doubt, that there is a lot of truth that has not been proven in a lab. This may be due to many factors. To name but a few: the topic has not yet been studied, there are flaws in the design of the study, the topic is too complex for reductionist evaluation.”
I think the last factor you mention is too often ignored, and that the infinitely complex web of systems in which we find ourselves often eludes our simplistic — albeit logical — analyses. For this reason I appreciate the humble approach of permaculture — to start out by assuming that the natural systems that are in place probably got something right, and that we would do well to imitate them.
With regard to your point about lambsquarters, I just wanted to throw in there the fact that Dr Ingham frequently states that soil scientists agree that all of the nutrients needed by plants are present in abundance in every type of soil on the planet, but that they are simply not all in a bioavailable form. Thus, she says, we need the proper biology in place that can make these nutrients available. I would suppose that (in theory) some plants might accomplish this task better than others. As you and everyone else has noted, someone should try to verify this hypothesis empirically.
Good article, thanks! So we need more controlled studies in this area!
Anecdotal evidence provides us with the reason for scientific research.
It would also be good to know exactly why certain plants can absorb
certain minerals.
I’d like to start using vetiver as it has extremely deep tap roots, has grass like leaves and has types that are sterile and so avoid being a weed. It makes sense that the ‘accumulator’ would need roots deeper than the crop intended to follow otherwise no new depths of minerals are being accessed.
David – what were your experiences with using vetiver as a dynamic accumulator?
Nice article, some of my favorite plants in these pics. The fact is if there aren’t any minerals in the soil, they won’t be in the plant, accumulator or not. I looked at the chart from James Duke, which was very interesting, but as I looked at it I realized this is true for this patch of soil only. Go 10 feet over and the nutrient content will be totlly different. The plants can’t accumulated what isn’t there. So it seems mineral soil ammendments are neccessary to ensure nutrient value of the food grown in it. Wood ashes from your woodstove or fireplace are an excellent “free” form of minerals for the garden.
Great comments here! The dogma of materialistic science is strong, and I appreciate the (slight) nod to the fact that other modes of inquiry might also have value. Perhaps that could be a strongpoint of the permacultural approach? What if permies pursued a science of qualities in addition to the typical science of quantities? The result would be a much broader and more accurate picture, no? Biodynamics has a leg up — with about 80 years of sound, qualitative research. See for instance any work by Lili Kolisko.
Nice article, John. I saw this related article today that adds a bit to this discussion. http://permaculturenews.org/2014/03/18/comfrey-really-improve-soil/
It could be that the benefit of plants like comfrey lies not in its ability to accumulate minerals, like some kind of fertilizer generator, but simply in its ability to move minerals from one part of the soil (deep) to another (the surface) in a way that helps neighboring plants with different root configurations to absorb the minerals. What this means is that if someone proves that comfrey benefits adjacent plants, the reason may not be accumulation, but transport.
[…] https://tcpermaculture.com/site/2015/01/07/the-facts-behind-dynamic-accumulators/ […]
I loved the post! And even though deciduous trees are not lumped in with dynamic accumulators, they probably should be. There is research showing the depths to which tree roots will reach. And there is a lot of research which shows how mineral rich the fallen leaves are, and how bio-available the minerals are. A quick compost turned every other day by man, or a slow compost in a natural forest – either way, trees and their fallen leaves enhance the surface soils.
Excellent post. I believe that dynamic accumulators could be very useful for 1) bringing up nutrients from below crop root systems, 2) making “fixed” nutrients plant available (particular P, which is often present but not available), and 3) bio-weathering. On the other hand, you are correct about the research needs. Just to add other variables not always recognized: PPM alone doesn’t tell us much if we don’t know the weight per unit area (a few little chickweed plants might not give us much Fe even though the ppm looks impressive). And where is the ppm concentrated? In the leaves or the stem? What is the bioavailability of nutrients in the leaves versus the stem or roots? How long do I need to let weeds grow to get their root systems down below the roots of my crop root depth? The value of a 3-inch succulent lambs quarters will be different than a 3-foot lambs quarters due to woodiness, depth of rooting, ratio of leaves to stem…All very good opportunities for research!
Gloria Flora, of the International Biochar Initiative, and I have been talking about putting together a manual for field trials in permaculture, so that those of us who are interested in doing citizen science to research different permaculture techniques would have a set of standards to follow. We haven’t done it yet, but the International Biochar Initiative does have one for biochar research which I think is very applicable to other permaculture research. Those who are interested can download a copy of it at International Biochar’s website, or follow this link:
http://www.biochar-international.org/sites/default/files/IBI_Biochar_Trial_Guide_final.pdf
[…] They may help bring back to the surface nutrients that would otherwise runaway in the depth of the ground (this is the concept of dynamic accumulators) […]
well written and researched – feel the same after 30 years in R&D – also am stealing your stolen quote “The plural of anecdote is not data.” – which in 2017 has an all to familiar ring to it.