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What's The Deal with Syntropic Agroforestry?

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At first glance, it sounds like one of those "hey I've got the magic beans to make your landscape extremely productive even if Aluminum saturation is 90% and every nutrient is deficient in your soil" approaches.

The guy who coined the approach, Ernst Gotsch, seems to be a pretty intelligent person, although I get sleepy watching his presentations, and have to muck through his diatribes about the usual environmentalist gripes in order to glean a few nuggets of gold. What's missing is the hard data. Or perhaps it's not presented well and I haven't found it yet with my less-than-extensive internet searches. Most everything seems anecdotal, although it looks like a good approach to regenerative agriculture as far as I can tell.

Okay he started with a desertified piece of land with "soil pH from 3.7 to 4.5" in northeastern Brazil. What was the aluminum saturation? What was the CEC? Which species did he use in the areas that were pH 3.7? Did anyone conduct a geological assay of the soil using Inductively Coupled Plasma - Optical Emission Spectrometry? What elements were deficient?? Were any of these elements imported to the landscape in the form of amendments, fertilizers, manures, mulches, etc? Was any liming ever done during the reforestation process? What was the average annual precipitation of the area?

Hard to believe that a property that was a total desert with soil so poor that farmers "couldn't even produce a pineapple", was able to be converted into a thriving rainforest ecosystem without any irrigation nor inputs besides seeds and hard work - but that appears to be the insinuation. I guess if it took the guy thirty years to get to that point, it makes more sense. But I imagine the better part of the first decade saw little to no production, which wouldn't be practical for most people lacking a swiss bank account.

How does pruning tall trees effectively mine subsoil of elements? I can understand that, but what if those elements aren't there in the first place? Surely healthy populations of microorganisms can access unavailable nutrients, but I don't believe they have the ability to add elements that aren't in the soil profile or parent materials in the first place. If I'm wrong, someone please tell me there's a microorganism capable of the alchemy necessary to start adding gold to my soil. Now that would solve some of my problems. I have a lot of questions about this approach, which sounds like it's being marketed as a silver bullet solution.

For the uninitiated, here's probably the most watched video on the topic:

Its like weeds they grow on poor soil then rot and replenish it. Brazilian pepper tree in Florida grow like weeds in soil with few nutrients and over time the leaves rot and create top soil. I guess they pull nitrogen out of the air and I don't know how they get micronutrients. Just really big root systems that can scrape small quantities together i guess.

I am only generally familiar with these systems, but here are a few observations from common agricultural knowledge. Clay is actually pretty fertile soil. It mainly lacks nitrogen. About 10% of the world's nitrogen is fixed from the atmosphere by lightning. Organic matter mineralizes back to nitrogen and other components through biological processes over time. For every 1% increase in soil orgnic matter content, nitrogen inputs can be reduced by 10% according to recommendations I have read from the University of Nebraska. Logically, building up organic matter will supply the missing ingredient in a clay soil. Organic matter also improves water retention and infiltration and can absorb harmful elements like aluminum (similar to how activated charcoal absorbs odors in your fridge). Shade also reduces transpiration. I think those factors account for most of the benefits in the system.

I live pretty close to Ernestís farm. Degradation is real here and itís pretty easy for them to destroy land temporarily. Calling it a desert is an exaggeration. Not sure how much rain he gets as Iím closer to the coast but our averages are 2000+mm and he has to be near that. The Atlantic forest regenerates without any intervention in many parts of Brazil so Ernest accelerated this process only. If you leave pasture alone it will become forest in about 5-10 years. The other component of regeneration is microbes making nutrients available in soil that otherwise wouldnít be. Increased rotting biomass contributes to this.

I will say thereís lots of hype around syntropic stuff which is innovative and interesting hype aside. Two big weaknesses I see are labor and commercialization. Ernest did everything manually. Much of the techniques require either expensive machinery often not accessible to small or medium farmers outside the us and Europe or plentiful cheap labor which is also less and less likely in many rural areas. The other weakness is if you plant a crazy amount of crops you often canít sell most of it if supply chains donít exist where you are. These issues are surmountable but worth mentioning because in my limited experience most syntropic projects are noncommercial, small scale, or done by independently wealthy people. There are some medium scale things happening in Brazil but itís all initial stages, funded, and pending the test of time.


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