RICE BRAN & SUBSTITUTES FOR IMO-3
WHAT IS IMO-3?
IMO is Indigenous Micro-Organisms, the foundation of practicing KNF, Korean Natural Farming. It is a culture of local soil microbes. IMO-3 is the step most people have the most trouble with.
The keys to success are cultivating it in a proper location, with the proper medium, and paying close attention to the 3 Chi, the Vital Forces of air, moisture, and heat.
We collect IMO from the soil on hard-cooked rice (IMO-1) and then put the culture into dormancy with dry, raw sugar (IMO-2). This is the best stage for long-term storage.
When we are ready to use it, we first amplify the culture (IMO-3). Then, we mix it with local soil (IMO-4) to acclimate the culture to the planting soil. The last optional step is to enhance the IMO with compost, manure, or biochar (IMO-5).
IMO TECHNOLOGY STEPS
1. Collect 2. Sleep 3. Multiply 4. Acclimate 5. Enhance
A spoonful of the culture literally becomes a large pile of IMO crumbles used to inoculate the soil for planting and for animal bedding and feed.
We collect our IMO culture on simple starches (sugars) of white rice. This allows everyone in the soil to come to the party. In order to amplify the culture, it’s going to need some nutrition. However, the goal is to keep the soil ecosystem as intact as possible. We want to install what we collected as closely as possible.
Master Cho developed his IMO technology using rice bran for the IMO-3 stage. He found it has the nutrition the soil microbes need, and for him, it was always available and cheap, even free, as it is a common agricultural waste product in South Korea.
You, however, may not be able to source rice bran for a good price or at all. Ideally, you should be using a waste product available in your area, which may not be rice.
This is a guide to help you determine the best alternative to rice bran for you for the amplification stage (IMO-3). The goal is to substitute rice bran with a medium that has a pattern as similar to rice bran as possible.
For success, it is important to consider more than the carbon and nitrogen balance, more than just nutrients. Keep an emphasis on aerobic bacteria and beneficial fungi. You must also consider and balance the 3 Chi, the Vital Forces of air, water, and heat for proper microbe-culturing conditions.
Keep in mind that the IMO-3 pile is not the same as organic composting. The goal of composting is to break down organic matter into soil. IMO technology has a very different goal.
The goal with IMO-3 is to take a culture of soil biology, keeping the culture ecosystem as intact as possible, and amplify it.
Keeping the culture as intact as possible is very important. If you want to have a specific type of soil biology, the technology protocol is to collect from an appropriate site. Trying to manipulate the structure of the ecosystem after collection is haphazard at best.
This is a technology that was perfected over several decades in locations all over the world. Trust the technology, especially while still learning it.
The IMO technology was perfected using rice bran as the substrate medium for amplifying the collected culture of soil biology. If you can get rice bran, it is best to use rice bran, especially while learning the techniques. You will be more successful in making substitutes if you first understand how the process works as intended.
RICE BRAN
Rice bran is the outer layer of the rice grain that's removed during the milling process to produce white rice. It's a nutrient-dense byproduct with excellent properties as a microbial substrate. The analysis of rice bran gives an indication of what to aim for when choosing substitutes.
Macronutrients
Proteins (12-15%)
Essential amino acids
Oils/Fat/Lipids (15-20%) (rich in healthy oils)
Gamma-oryzanol (antioxidant)
Tocopherols and Tocotrienols (vitamin E)
Carbohydrates 34-52% (including dietary fiber)
Dietary fiber (20-25%)
Fiber 7-11%
Ash 7-10%
Micronutrients
Vitamins B-complex (thiamine, riboflavin, niacin), vitamin E (tocopherols, tocotrienols)
Minerals Phosphorus, potassium, magnesium, calcium, iron, zinc, manganese
Bioactive Compounds
Antioxidants Oryzanol, ferulic acid, phytic acid
Phytosterols β-sitosterol, campesterol, stigmasterol
Polyphenols Various phenolic acids and flavonoids
Anthocyanins
Flavonoids
Properties Beneficial for Microbial Cultivation
High carbon-to-nitrogen ratio
Readily available carbohydrates and lipids for microbial energy
Diverse micronutrients supporting enzyme production
Natural pH buffer capacity
Porous structure allowing good aeration
Rice bran makes an excellent substrate for soil microbes due to its balanced nutrient profile, which provides both readily available nutrients and more complex compounds that support diverse microbial communities and sustained growth.
How Lipids (oils) in Rice Bran Affect Microbial Culturing
Energy-dense substrate
Lipids provide approximately twice the energy per gram compared to carbohydrates, offering concentrated energy for microbial growth
Fungal promotion
High lipid content particularly favors fungal growth, as many fungi can efficiently utilize lipids
Slow-release energy
Lipids break down more gradually than simple carbohydrates, providing sustained energy for the microbial community
Biofilm formation
Lipids contribute to the development of biofilms that protect and stabilize microbial communities
Cell membrane development
Provides essential building blocks for microbial cell membranes
Signaling compounds
Some lipid derivatives serve as signaling molecules in microbial communities
Rice Bran Alternatives for IMO in KNF
This discussion explores rice bran (the ideal substrate for Indigenous Micro-Organism cultivation in Korean Natural Farming) and potential alternatives for those without access to rice bran or facing high costs.
The emphasis is on aerobic bacteria and beneficial fungi, maintaining the collected soil culture as intact as possible without introducing competing microorganisms, and the importance of lipids in providing energy and supporting beneficial fungal growth in the microbial communities.
Critical Factors for Alternatives
Physical properties Particle size and moisture-holding capacity should match rice bran
Lipid content High lipids (8-20%) support fungal growth and provide slow-release energy
Processing Minimal processing preserves bioactive compounds
Structure Fine, consistent texture supports uniform colonization
Freshness Particularly important for high-lipid materials to prevent rancidity
Alternative High-Lipid Substrates
Wheat germ 8-14% lipids, with excellent nutrient profile
Hemp seed meal 10-15% lipids after partial oil extraction
Corn germ 18-25% lipids, a byproduct of corn processing
Flaxseed meal 30-40% lipids, though particle size may require adjustment
Coconut Meal 8-12% lipids, good moisture retention, may select beneficial fungi over pathogenic
Considerations for High-Lipid Alternatives
Rancidity risk High-lipid materials can become rancid; fresher is better
Particle size adjustment Most seeds need grinding to match rice bran's structure
Protein to lipid ratio Rice bran has a balanced ratio that should be mimicked
Processing level Minimally processed options retain more bioactive compounds
Of these alternatives, wheat germ and corn germ most closely match rice bran's overall profile. Partially defatted seed meals can also work well if processed to achieve the right particle size.
Grain-Based Alternatives
Wheat bran/middlings Similar nutritional profile with good protein content
Oat bran High in beta-glucans that support beneficial fungi
Barley bran Contains enzymes that help initiate microbial activity
Spent brewery grains Rich in nutrients and widely available in areas with breweries
Local Agricultural Byproducts
Cornmeal/corn bran Available in corn-growing regions
Coconut Coir and Bagasse In tropical regions, can be a good structural component
Millet or sorghum bran Common in Africa and parts of Asia
Analysis of Some Key Substrates
Rice bran High lipid content (15-20%), balanced nutrients, ideal particle size and moisture properties
Wheat mill run Higher protein (15-18%), moderate fat, good all-purpose substrate
Crimped oats Moderate protein and fat, high in beta-glucans, excellent moisture retention
Coconut meal Good lipid content (8-12%), favorable texture, supports sustained microbial growth
Bagasse Very high fiber, low nutrients, excellent structure but requires supplementation
Nut husks Poor substitutes due to high lignin, low nutrients, antimicrobial properties from tannins and phenolic compounds, and may take longer for inoculation. They may do best after partial composting or mixed with other, more nutritious materials.
Nut meals (almond, walnut, macadamia have better nutritional profiles) and Nut processing waste (excluding husks) often have higher nutrient content.
Hemp Seed Meal Physically similar to rice bran, but with a higher protein content and different nutritional profile.
Spent Brewery Grain
Spent brewery grain (SBG) is the solid residue remaining after the mashing process in beer production, often free or low-cost. It offers balanced nutrition but may contain brewery sanitizers, which kill microbes if not properly rinsed.
Sweet Potato Peels
While not a perfect substitute for rice bran, sweet potato peels represent one of the better starchy alternatives, particularly when properly prepared and balanced with complementary materials. Their higher fiber content and complex carbohydrate profile create a suitable environment for diverse microbial communities.
Best Alternatives
Wheat bran Similar structure and moderate lipids
Wheat germ and corn germ Closest lipid profile to rice bran
Coconut meal Good balance of nutrients with favorable texture
Seed meals When properly processed to match particle size
What about Woodchips?
The benefits of the physical structure of woodchips include improved aeration, moisture regulation, thermal insulation, and long-term structure. These properties make the use of woodchips popular.
They also seem popular as a way to increase fungal dominance. However, there are many types of fungi, and the types matter.
Some fungi are beneficial for plant nutrition, and these fungi are highly desirable. However, excessive fungal dominance, especially of microbes that break down complex wood compounds rather than forming plant-beneficial relationships, are not. Nutrient cycling and uptake are the two main functions of IMO in the planting soil.
Additionally, decomposing wood can temporarily tie up nitrogen, and the plant-supporting microbial community may take longer to establish.
It is best to keep woodchips in a compost pile or as animal bedding, not used to amplify a culture of IMO. If you want a fungally dominant IMO, choose a collection site that is fungally dominant and also matches the ecosystem of the crops, rather than haphazardly trying to change the ecosystem during culturing.
Better Approaches
Since our goal is enhancing plant nutrition through microbial relationships, maintaining an emphasis on aerobic bacteria and beneficial fungi that directly support nutrient uptake is more appropriate than shifting toward wood-decomposing communities.
Consider plant residue or ramial wood instead of woodchips if additional structure is needed. Dried plant stems/leaves may better support the desired microbial profile.
Dried plant residues can include crop stalks, dried grass stems, non-woody plant parts, and small herbaceous stems that break down more readily than woodchips.
Ramial Chipped Wood (RCW)
Ramial wood specifically refers to small diameter, less than 7 cm (2.7in), branches from deciduous trees that are rich in nutrients and have a lower lignin content compared to larger woody material.
Ramial wood is actually an excellent choice because it tends to support the kind of soil biology that enhances plant nutrition rather than just decomposition.
Contains more cambium and phloem tissues that are more nutrient-rich than heartwood or larger branches
Decomposes more readily by beneficial soil fungi without causing nitrogen immobilization
Supports mycorrhizal networks rather than primarily saprophytic fungi
Promotes a more balanced microbial community that includes beneficial fungi without overwhelming the system with slow-decomposing lignin
The key difference between ramial wood and regular woodchips is that ramial wood supports the development of humus and nutrient cycling systems rather than simply providing carbon for decomposition.
Green prunings, when dried to appropriate moisture content, can provide structure without the heavy lignin content of mature wood.
MY EXPERIMENTATION
When I learned KNF in Hawaii, rice bran was not available. For a while, wheat mill run was available, but not for long. Without these two mediums, I was forced to experiment early.
Some local farmers had some success using their own bagasse (sugarcane waste). This has little nutrition, however. And since commercial sugarcane production had already shut down in Hawaii, I did not have access to this source either.
I used grass clippings from my pastures for my Inoculated Deep Litter Systems (animal bedding), but this did not work for culturing IMO-3. Grass clippings are mainly cellulose. And while they can be inoculated, they did not have enough nutrition to grow an IMO-3 pile.
This is basically the same effect seen with bagasse. Both can be useful for supplementing piles for proper moisture and air, but they lack the nutrients for the microbes to grow when used alone.
I then started using partially composted macadamia nut husks. I found success with this. You can see from the research above that the problem with nut husks is the lignin, which inhibits microbial growth. Partially composted, this is no longer a problem.
Once in the South Pacific, I started working with sustenance farmers. I needed to find something that they would have access to. I also knew that if it required much labor, they wouldn’t try it.
Sweet potatoes are a major staple, typically steamed and then peeled. While peeling is labor intensive, it is something already being done as part of the cooking process. I started inoculating cooked peels on a small scale and found it works well, and the results in the gardens were spectacular.
NOT RECOMMENDED
Woodchips see details above
Coffee grounds Studies show residual caffeine can be detrimental to microbes
Whole Starchy Root Crops such as sweet potato or cassava/manioc (all parts of manioc roots should be avoided altogether)
Mushrooms and mushroom cultivation materials
Coconut Flour
Finely Ground Flour (of any type) does not allow enough airspace for cultivation
Grass Clippings mostly cellulose
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