organic gardening as carbon sequestration!

[rainbowgardener]

See:

https://www.organicconsumers.org/article ... _29911.cfm

https://rodaleinstitute.org/assets/Regen ... 140418.pdf


Rodale Press put out the above article claiming if we switched all our agriculture to "regenerative organic agriculture," we could sequester much of the carbon dioxide we are currently putting in the atmosphere in the soil instead. Their list of techniques included in "regenerative agriculture" will sound very familiar to us here:

"cover crops, residue mulching, composting and crop rotation. Conservation tillage, while not yet widely used in organic systems, is a regenerative organic practice integral to soil- carbon sequestration." (conservation tillage is no-till or minimal tilling)

Moving crop rotations away from monoculture with fallow and towards polyculture with no fallow increases soil biodiversity and sequesters carbon. For instance switching a wheat-fallow rotation to a wheat-sunflower or wheat-legume rotation was found to increase soil organic carbon stocks significantly, and a continuous barley system more than doubled soil carbon stocks compared to a barley-fallow system. Integrating seeded grass species as cover crops, living mulches, or in rotation is a powerful means of increasing soil carbon due to the deep, bushy root systems of many of these perennials. Both cover cropping and enhanced rotations result in continuous cover, which also increases soil microbial biomass carbon by ensuring available energy and root hosts for bacteria and fungi."

So when we here talk about increasing the organic matter in the soil and increasing the soil microbial communities, both of those things are CARBON, held in the soil.

"after only one application season of amending with compost, soil organic carbon and aggregate stability increase significantly compared with non-amended soils. Amending with composted manure in particular shows great promise for soil carbon sequestration. In a 10-year trial, fields with a crop rotation utilizing composted dairy manure sequestered more than two metric tons of carbon (Mg C) per hectare per year, while the paired conventional farming system lost carbon"

"The goal of regenerative organic farming for carbon sequestration is not only to increase soil organic matter content through the practices highlighted here, but also to ensure the longevity of that carbon in the soil. Since the carbon cycle is dynamic and the study of soil in-situ is difficult, the factors influencing retention time of carbon in soil are inherently complex and not yet fully understood. However, rapid, stable carbon sequestration under the conditions encouraged by regenerative agriculture is possible. Fungi, depth in the soil profile and recent understandings regarding the humic fraction of soil all play a role. An Iranian trial of no-till, low-input corn production showed that regenerative methods using composted manure were able to raise soil carbon by 4.1 metric tons per hectare per year in just two years compared to .01 metric tons for the paired tilled system using synthetic fertilizer."

"While the understanding of soil carbon stabilization mechanisms is evolving, it is clear that soil biota play an important role here. In general, there is a positive relationship between abundance of fungal biomass and soil carbon. Recent research on carbon sequestration in boreal forests suggests that root-associated, or mycorrhizal, fungi are predominantly responsible for fixing soil carbon, and for fixing it over long time periods to such an extent that it is consequential to the global carbon cycle."

"How carbon acts in this subsoil range is poorly understood, but increasing rooting depth, application of irrigated compost (compost tea), choosing deep rooted grass-legume cover crops and encouraging earthworm abundance are all promising pathways for introducing carbon to depths where it is likely to remain stable over very long periods."

This is the most hopeful thing I have seen in a long time, but for it to make a difference in our situation, it still requires large scale change from giant petroleum fueled farm machinery, petroleum based synthetic fertilizers, acres of monoculture, lots of chemicals to an organic natural agriculture system. Do we have the will to make this happen?

[applestar]

You are right -- all of this sounds familiar.

Cover cropping is the one that I don't always do, though most of the time, I have something growing in succession. It's time to think about sowing winter cover crop grains, and I was wondering again if I could sow mustard cover crop where the tomatoes will be planted next year -- this is supposed to help prevent soil-borne diseases.

I've read articles of full scale small and large farm operations using these techniques --- I think many of them were participating in this or other research, and one of the things that struck me as being mentioned is how complicated it all is compared to the conventional agribusiness technique. But they said these techniques really work and they wouldn't go back.