15 Comments
User's avatar
Kathryn Alexander, MA's avatar

Alpha, I’d hug you if I could! Not only is this brilliant your writing brings clarity, depth and meaning. I’ve watched you grow over the past year or so and you are a wonder to behold! Thank you! 🙏 🎉

Alpha Lo's avatar

thanks Kathryn!

John Lovie's avatar

This is great, thank you. Water science we can use, written so we can follow it.

Kathrin Bohr's avatar

Deep thank you, Alpha

Felipe Rossi's avatar

What a great article! Thanks for putting it out there. Loved the equations and how you manage to translate them

Into easy to understand sentences. I’ve been reading about soil and the importance of it in the context we are right now and the way we have been growing our foods! How we treat our soil could determine our future! Thank you again 🙏🏾

Josh's avatar

Thank you! I very much benefited from you walking me through these equations.

Alpha Lo's avatar

thanks. I debated putting the equations in, then thought it would be a good chance to walk people through how equations work.

Josh's avatar

One question: the equations don’t seem to factor for complexity of plantings, whether the geology is characterized by horizontal or vertical fracturing and depth of top vs subsoil. Are you aware of any coefficient charts that would address these factors like there are for runoff in built environments?

Alpha Lo's avatar

HYDRUS or SWAT includes lookup tables for vegetation type, root depth, and soil properties

Alpha Lo's avatar

If we want to see how a watershed might respond to widespread regen ag shift, change the K values in your model, and see how that affects water retention and flow.

Deanna Pumplin's avatar

Your explanations open worlds! I'm feeling excited about using Didi Pershouse's (or other readily available instructions on measuring permeability) instructions and your descriptions to increase my understanding of the conditions in our small orchard. I'm glad you'll be a part of the Global Earth Repair Convergence in May.

Alpha Lo's avatar

cool glad you like the explanations.

Leon S's avatar

Really great explanation Alpha, I've thought about these things a lot but didn't know about these equations. So how would we measure k? Would it be a permeability test, timing the water to disappear into the soil? I remember there's a test where you get a pipe maybe a couple of inches radius and hammer it partially into the soil, pour a known amount of water quickly into it, time how long it takes to permeate. Wish I'd done all these simple tests when I'd started but I was "too busy". Sigh.

Alpha Lo's avatar

Yeah you can time how long the water takes to disappear through soil as an approx to K. Like put it in bucket and then pour water on it https://www.youtube.com/watch?v=ekYwJzF1seg . If you want a more high tech way to do it https://www.youtube.com/watch?v=sRDXiJ3Fq6Q . Heres a service https://www.globalgilson.com/blog/soil-permeability-test?srsltid=AfmBOor1l8Ny1nI7f5va92QnaCr65uB14Se9FvP-Q1NgfVNYiEVp7mPs . And general description https://www.tensarcorp.com/resources/articles/the-permeability-of-soils-explained

Michael G's avatar

Thank you for the back link to this Part One article from the Part Two article. I’d missed this one while in the cloud forests of Central America. Your explanations and translations of mathematical equations to plain English are way more interesting and helpful than the dry (sorry for the pun) version I got in a Soil Mechanics class in university almost fifty years ago.