Since I first wrote about dynamic accumulators in 2013 and again in 2014, there has been a fairly fundamental change in presentation around the Net. The Oregon Biodynamic page now produces a “404” message although the information continues to exist in the Internet Archive. And Toby Hemenway and Eric Toensmeier who included the Kourik table in their books have now changed their views. John Kitsteiner, a permaculture practitioner, has blogged about The Facts Behind Dynamic Accumulators and his post has been posted at Geoff Lawton’s permaculture news website.
So it would seem that this set of information is being removed, more or less, from the permaculture environment. Hopefully, it will be replaced by more substantiated information.
I think that a very strong case can be made for not needing the function that dynamic accumulators supposedly served – that of mining micronutrients which could then be made available to the plants in one’s food forest or vegetable garden via chop and drop, plant teas, or compost. It doesn’t hurt to use so called dynamic accumulators but their function is not as essential as it was in light of a substantiated, more holistic, soil-based approach.
Elaine Ingham says:
if the proper sets of organisms are present in the soil, and you are growing plants so that there is food for those organisms, nothing else is needed. The plant puts out the exudates from photosynthesis to feed those bacteria and fungi that specifically make the enzymes to solubilize the needed nutrients from the rocks, pebbles, sand, silt, clay and organic matter… There is an infinity of all plant-required nutrients in any kind of parent material. There is no parent material on the planet that lacks the nutrients needed to grow plants. Until the day you run out of rocks, sand, silt, or clay, there should be no need to apply a mineral fertilizer
Whenever Ingham says that “all agricultural soils have the needed nutrients in them to grow plants. Everything except carbon dioxide, sunlight energy, and nitrogen are in the soil.“(page 24), the immediate intuitive response many is “How can that be? The land has been farmed continuously for years and is depleted and produces very little. There are plenty of examples of this.” And that’s correct in the scenario as it currently exists. But there are examples where land has been commercially farmed continuously for years on a large scale with no chemicals and the yields exceed those of surrounding farms.
Gabe Brown of Bismarck, N.D. has used cover crops and no till for 20+ years. His fields haven’t seen commercial fertilizers since 2008, and it’s been 12 years since any insecticides or fungicides were used. And after having applied herbicides once every two or three years in recent times, the plan for 2013 [was] to completely eliminate such applications and let the cover cocktails and mob grazing do their thing. He may, in fact, now be totally chemical free. The county average corn yield where the Browns live is 100 bushels per acre yet their average yield is 127 bushels per acre which is achieved at a cost of only $1.42 per bushel. The average cost to produce a bushel of corn in the United States is over $5.00 per bushel. And he’s not the only one doing this.
OK, so it’s about building soil organic matter, not disturbing the soil by tilling, and never leaving the soil uncovered. If you do that, you will have a healthy soil microbiology including mycorrhizal fungi.
Mycorrhizal fungi explain both what Elaine Ingham is saying and Gabe Brown’s results. Mycorrhizal fungi form symbiotic relationships with most of the plants on the planet. In exchange for sugars from the plant, mycorrhizal fungi provide nutrients and possibly water to the plant. You can do a soil test and it will tell you, among other things, which nutrients and micro-nutrients your soil is lacking in. If you do a total soil test, you may find that what your soil is apparently lacking is, in fact, there. Soil tests are designed to detect and measure nutrients that are available for plants to uptake. Total soil tests include detecting and measuring nutrients that are not in a form that plants can uptake. Mycorrhizal fungi in the soil will transform these nutrients into a form that plants can uptake.
What if the total soil test shows that you a deficiency in some nutrients? This is where mycorrhizal fungi come in. They form networks. Research has established that they network to at least 30 metres although “[t]he role of mycorrhizal networks in forest dynamics is poorly understood because of the elusiveness of their spatial structure. ” Research has determined that mycorrhizal fungi associated with one plant connect with mycorrhizal fungi on adjacent plants:
The indicated ability of AM fungal mycelia to anastomose in soil has implications for the formation of large plant-interlinking functional networks, long-distance nutrient transport and retention of nutrients in readily plant-available pools.
Mycorrhizal network modelling has determined that [mycorrhizal networks] facilitate transfer of C, nutrients, water, defence signals and allelochemicals
Although much of the research is either speculative or says that much work still needs to be done, the possibilities are significant: if nutrients in plant-usable form can be moved from an area of higher concentration to an area of lower concentration based on plant needs, then areas naturally deficient in a nutrient(s) might still be productive to us if we manage the soil properly. It might also mean that degraded areas could be brought back to useful, healthy production.
And if the supposed function of so called dynamic accumulators is made redundant by establishing and maintaining a microbiology-rich soil, perhaps ongoing soil testing is also redundant. If you’re going to lab test, perhaps it’s better to test the fruit, vegetable or nut. If what you’re putting in your mouth has the nutrients that you need, then your soil management programme is working – the proof is in the