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Coffee Leaf Rust, Seawater Minerals, and 327 Miles of Roots

Dr. Drake covers a coffee leaf rust research trip to Mahina Mele Farms in Kona, done with Hector from the University of Hawaiʻi and Melissa from PBARC. The conclusion: years of conventional chemical farming killed the soil's immune system, and IMO trials showed about 60% better leaf retention even though the rust itself stayed on the plants.

The fix is diluted seawater with calcium, sprayed on the leaves, since chemical nitrogen shuts down root uptake of trace minerals like boron and zinc that rain has washed into the ocean. Liquid sulfur can knock the fungus back fast but also kills beneficial bacteria and fungus, so it needs a biological follow-up. He also flags mac nuts — fats, oils, husk, and charred shell — as some of the best local IMO-pile material, answers a listener's question about a thick batch of KNF cleanser (vinegar), and announces KNF classes in Hawaiʻi for November 2023 and January 2024.

The back half walks through Master Cho's "Natural Farming: The Microorganism" presentation — the best conditions for microbes (15-25°C, 60-65% moisture, 70% shade), how much biomass lives in a quarter acre of soil, what 40 years of composting does to soil aggregate structure, and the difference between a good and bad rhizosphere.

He closes with proliferation times: lactic acid bacteria double every 38 minutes at 25°C, while coliform bacillus doubles every 18 minutes at 37°C — a reason to keep IMO piles cool — plus the fact that one coffee plant's lateral roots can run 327 miles. He wraps up telling farmers not to worry about LAB shelf life and just use it fast.

Questions answered

  • 15:45 What did the Kona coffee leaf rust research find? — Poor soil from years of conventional chemical farming killed the plants' immune system; IMO trials showed about 60% better leaf retention.
  • 21:11 Where did the coffee's boron and zinc go, and how do you get them back? — Rain washed the trace minerals into the ocean; dilute seawater 1:20 to 1:30 with calcium and spray it on the leaves.
  • 23:51 Does liquid sulfur fix coffee leaf rust? — It knocks out the fungus fast, but also kills beneficial bacteria and fungus, so follow it with a biological cover.
  • 25:40 What's the best material for building IMO piles in the tropics? — Mac nuts — the fats, oils, husk, and charred shell make some of the best IMO piles around.
  • 29:30 Jerome's KNF cleanser came out thick after a month — is that okay? — Let it keep converting and test it with a pH strip; you want it under 2.4 pH.
  • 43:30 How many microbes live in a quarter acre of soil? — About 1,500 pounds of microbes live in the top seven to eight inches of a quarter acre, depending on organic matter.
  • 52:35 What does soil look like after 40 years of composting? — Fungal hyphae bind small particles into big aggregates with airflow and water movement, unlike compacted, uncomposted soil.
  • 56:27 What's the difference between a good and bad rhizosphere? — Good rhizospheres grow bigger leaves, fruit, and roots and feed more secretions to the soil; bad ones get eaten by root nematodes.
  • 59:53 How fast do IMO microbes multiply, and why does temperature matter? — Lactic acid bacteria double every 38 minutes at 25°C, but above 37°C coliform bacillus takes over, doubling every 18 minutes.
  • 1:09:10 How big is a coffee plant's root system really? — One plant's lateral roots can stretch 327 miles with over 10 billion root hairs.
  • 1:13:27 How long does LAB last in the fridge? — Don't worry about shelf life — use it within a month or two and keep making small fresh batches.

Topics: imo, lab, coffee leaf rust, kona coffee, rhizosphere, mac nuts, knf cleanser, vinegar, seawater, foliar spray, soil microbes, composting

KNF Office Hours is a free live Q&A every Sunday at 9 AM HST. Bring your question to pureknf.org/learn/questions or join live.

In this episode

  1. 0:00 Countdown
  2. 4:33 Intro and Welcome
  3. 6:26 I Ching Reading: Development (Gradual Progress)
  4. 11:20 Conservation vs Regenerative: Linear vs Exponential
  5. 13:53 Community Chat Recognition
  6. 15:37 Coffee Leaf Rust
  7. 17:49 Organic vs Conventional Farming and Coffee Leaf Rust
  8. 25:40 Mac Nuts Make Great IMO Piles
  9. 29:15 KNF Cleanser Came Out Thick
  10. 32:41 KNF Classes in Hawaiʻi: Nov 2023 and Jan 2024
  11. 37:57 Cho's Presentation: Natural Farming, The Microorganism
  12. 40:16 The Best Conditions for Microorganisms
  13. 43:36 How Many Soil Microbes in a Quarter Acre
  14. 52:12 A Field After 40 Years of Composting
  15. 55:46 The Bad and Good Rhizosphere
  16. 59:58 Microorganism Proliferation Times
  17. 1:05:31 Synergistic Mechanisms of the Ecosystem
  18. 1:08:54 327 Miles of Lateral Roots and Root Hairs
  19. 1:12:55 How Long Does LAB Last?
  20. 1:14:42 Thanks Folks! Long Live the Natural Farmer

Transcript

Auto-transcribed with Whisper. Click any timestamp to play from there.

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