This is the World Organic News whoops! The ChangeUnderground for the week ending 19th of October 2020.
Jon Moore reporting!
Decarbonise the Air, Recarbonise the Soil!
So I bit the bullet, changed the podcast name and artwork. Let me know what you think. So what can you expect with this momentous change? Pretty much what I’ve been doing. I’ve just adjusted the name to the content. But as I dive more deeply into this regenerative thing, I’ve started to question everything.
Back in episode 225 I disclosed by heretical views on compost. Since then and whilst researching, other “sacred cows” of the non industrial food production world have asked to be examined.
From simple things like “weed competition”, does this really exist or is it just assumed to be the case? Of course when we set up a no-dig garden in the correct manner, weeds are never an issue. But say we “overplanted” a bed with too many seeds/seedlings and one food crop was growing more closely than the books suggest. Is this really a bad thing? Do roots compete with each other? I don’t know but I’m going to run some test plots to see. Regenerative theory would suggest the greater the root numbers from different cultivars and species, the greater the biodiversity in our soil. The greater the biodiversity the more numerous the bacteria and fungi within the soil. That being so, the “overplanted” food crops should be receiving more nutrients through this ecological web underground and thereby be healthier. Difficult to run a row cultivator through, particularly in the chaos garden model (episodes 217 and 218).
While an interesting thought experiment, I’ll be planting a few beds to test the theory in the field and to find a possible optimal spacing if this idea shows promise. As unscientific as this sounds, my gut feeling is there’s a link to companion planting that will have a significant effect. We will see.
Another question I’ll be looking into and reporting back on is….. Crop rotation. Bare with me. If digging is not a thing to do anymore what about all the other assumptions we’ve made or followed because we read it or heard it somewhere? This one has been on my mind for awhile. Fukuoka grew rice, year in and year out on the same piece of dirt/magnificent body of soil so it is, at least, possible in one scenario. We only tend to rotate annuals and some perennials. I’m thinking of things like strawberries for the perennials. Bushes, shrubs and trees like blueberries, raspberries, brambles and apple trees all stay put. Now they’re fed or should be with mulch or manures or foliar sprays and keep producing. I’ve seen apple trees sprouted from an apple core tossed out a car grow and produce for years alongside part of the Great Western Highway in the Blue Mountains and no one was feeding them.
If we run a thought experiment with some pretty bold assumptions let’s see what happens. Given the following: we never plant just one crop on its own, we plant cover crops in the “off” season and we never use artificial fertilisers nor herb/pest/fungicides. We may even develop a permanent ground cover/cover crop into which we plant say sweet corn. Now conventional sweet corn has a wide spacing between rows and generous space with those rows. The plants are often side dressed with N of some sort and pest sprayed. Maize is deemed to be a fairly heavy feeder and to chew through available NPK in the soil. But let’s look at what just happened. Wide rows means sunlight falling on bare soil. That’ll kill off your soil biology and drive the remainder deeper. The N delivered at sowing or later on destroys the need for the maize plant to form any interconnection whatever soil biology exists. The delivery of nutrients is not dependent upon this soil food web so it never develops. Once again the cides continue this process. So at the end of the season there’s not a lot of artificial fertiliser left in the ground. Ipso facto, corn can’t be grown there again until at least one summer is skipped.
But wait! A no-dig system described earlier with even an annual cover crop would be creating the soil conditions necessary to grow maize, if we picked the right cover crop. Now if this was a perennial and the soil biota supporting that perennial cover crop was also the correct mix to grow maize, would it not make sense to feed the cover crop and the soil biota in an attempt to maintain the optimal growing conditions for maize. If the crop we garlic, then I’m pretty certain the cover crop and the soil biota would need to be different. So we get a place in our soils where they are perfectly set up of maize and then we plant something else into the space the maize had been and the soil biota might not be optimal for the new crop. It performs poorly and we conclude the maize had just used too much of the available nutrient store to allow the new crop to grow.
An alternative view would be that as the soil conditions, variability, moisture, structure and biota were perfect for maize, planting an unrelated crop into the same space requires a redistribution of the soil biota types for the crop. Think of it this way. If you suddenly introduce a new form of protein to your diet as you’ve decided to drop meat from your eating experience. You could choose any number of pulses as an alternative. Let’s assume you chose baked beans. A legitimate enough choice. What are the effects of this change, from meat seven days a week to baked beans seven days a week? I’m guessing a huge amount of bloating, gas and possible indigestion. But after a week or two the gut microbiome will have adjusted, breeding up more of the s[ecies that handle pulse as those requiring flesh to dwindle in number. I think a similar thing could be happening in the soil as we rotate crops. What if we could maintain the right soil biota and, therefore, the release of exactly the right nutrients from the soil to maize. Those same soil biota continue doing their thing all year, turning bedrock into available nutrients, subsoil and topsoil fed by the sugars the cover crops are generating as they photosynthesis. It is possible this could be a thing.
Obviously this is more than a one growing season experiment but it has me intrigued and excited to try out. This, dear listener, is my saying I’ll be producing this podcast for some years to come.
There are any number of heretical ideas out there in the ether but root competition and non rotation of crops are the two that really excite me. Chaos and permeance. Has a certain poetry to it that appeals to me.
If there’s any other horticultural heresy you’d like me to try, drop me an email: firstname.lastname@example.org and I’ll have a squizz at it. Can’t promise anything but if it peaks my interest we could have a crack at it.
There you have it, ChangeUndergound rebranding podcast episode in the can. From the 1st November 2020, I’ll have the ChangeUndergound Academy up and running on the World Organic News website. Lots of courses, short quick fixes through to longer “How To” and “Why To” are coming.
I try to always remember and underpin my work with our catch phrase: Decarbonise the air, recarbonise the soil!
Thank you all for listening and I’ll be back next week.
Growing a No-Dig Garden on Udemy
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Dr Charlie Massy
Dr Christine Jones ~ Amazing Carbon
4 per 1000
Diploma in Sustainable Living at the University of Tasmania