WNC CRAFT Farmer Round Table – Soil Testing “Demystified” w/Meredith Leigh

Even through the winter, WNC CRAFT is still going strong! With our CRAFT Farmer Steering Committee’s help, we were off to a good start with three themed farmer round tables to keep us cozy in these cold months.

What are Farmer Round Tables? They are open, farmer to farmer discussions geared toward a specific advanced farming topic. This ain’t no lecture series! We do have a designated facilitator but it’s a time for everyone to share ideas and experiences on a deeper more advanced level than we can get into at the CRAFT farm tours. All CRAFT Farmer Members are invited to commiserate and plan for the coming season. Become a member today to participate in next years’ sessions!

 

Soil Testing “Demystified” with Meredith Leigh of Living Web Farms

Meredith Leigh, the host for our first Round Table of the 2019 winter season, has been farming for a long time; for just as long, she’s been jumping around to use different soil tests. Eventually, she got into Elaine Ingham and her biological approach to soil health. Once she got into the biology, it changed her soil amendment approaches and her approaches to soil testing analysis.

Elaine Ingham’s general philosophy is that everything you need is in the soil already, and all you need are the tools to unlock it (ie; biological components of the soil). If a plant is healthy enough, it’s going to be photosynthesizing and turning sun energy into biomass, which is then feeding the soil. The “build it and they will come” rule works decently well when you’re not tilling, but you have to work pretty hard if you’re tilling as every time you aerate you’re destroying the biological components of the soil. Feeding really high nutrient foods (compost, etc.) will cause a feeding frenzy for the microbes, so it’s important to also provide ‘slow’ foods, like woodchips and rock dust.

The importance and degradation of micronutrients in soil (and therefore in our food) have been fascinating to her. Although we think and are told that there’s an average nutrient content of a food, there’s not because every soil that the food is grown in is varied and equipped with various levels of micronutrients. Meredith is mostly interested in looking at the composition of the soil and helping that interpret what can grow on your soil and what your soil needs. But, you need to look at it over time and repeatedly in order to get an accurate picture.

Here’s some good basic farmer friendly definitions of various soil terms that you’ll see on your returned soil test:

• Cation Exchange Capacity (CEC) — You can think of this as like a bank of nutrients. You need to have a good balance of water, minerals, and sun to have plants grow well. The problem with strictly looking at CEC is that doesn’t talk about AVAILABLE nutrients, just nutrients that are present in the soil. CEC is interesting, but doesn’t give you the cations that are available to your plants.
• Potential Hydrogen (PH) — the acidity of the soil. If it’s being measured in soil tests it’s usually being measured with water, but plant root exodus are actually slightly acidic which makes the readings on soil tests inaccurate. The Albrecht test mimics the slight acidic nature of root exodus for more of an accurate measurement.

One farmer suggested that once you commit a specific type of soil test, you want to stick with it in order to get consistent results. That being said, not all soils tests are created equal! Here’s a list of soils tests we discussed in the roundtable.

• The most common that folks use is the NCDA test.
  • A bit contentious as it doesn’t test for micronutrients and often gives recommendations based on conventional systems.
  • Meredith would recommend sending the same soil sample to the state and an Albrecht style lab to compare.
• Nutrien Ag Solutions (Albrecht) — has more details on micronutrient and macronutrient availability.
  • Meredith is hoping to remineralize her soil based on the Albrecht conditions this year.
• Crop Services International offers the Lamot test, base saturation, and CEC test.
• Waypoint Analytical does an Albrecht style test (which is also known as Reems test).
• Environmental Quality Institute offers heavy metal and pesticide tests.
• Kinsey Ag services in Missouri. Tells you to the pound what you want to apply to the fields.
  • Dawback: Kinsey’s lab focuses on getting the calcium and magnesium without taking into account the phosphorus. By organic standards, you can’t add phosphorus without adding calcium, so this often throws the balance off.
  • Harvesting multiple times from one piece of land is essentially starting over, nutrient-wise — Kinsey lab recommends fertilizing each time you harvest a crop.
    • Kindsey’s lab will do “maintenance” nutrient level recommendations, “slowly building levels”, and “high building” level recommendations so you can keep building on your nutrient levels, if desired.

The Bionutrient Food Association (and founder Dan Kittredge, who has come previously to Organic Growers School events) has some really interesting approaches to soil and its relationship to human health. They encourage Albrecht-style soil analysis, which is totally different than what the standard soil tests through NCDA does (which mostly focus around “SLAM” Analysis which stand for Sufficient Levels of Available Nutrients). These tests generally wash the existing nutrients out with water or acid, and their suggestions are usually nutrients that are more appropriate for a conventional farming system; because of the biological systems present in organic soils, you can’t make recommendations for chemical fertilizers that are the same for organic systems. The Bionutrient Food Association also recommends 75 lbs of sea salt and 2-10 tons of rock dust/acre (Volcan Materials Company was suggested as a good source for this. Keeping in mind all quarries around WNC are granite is important.) This focus on pre-biotics and the micronutrients available in these rock supplements is a pretty unique recommendation, although salt use on soils spans back to native agriculture techniques.

 

Meredith uses Johnson-Su composting bioreactor composting method (which was designed originally for quick composting for dairy manure.) You don’t have to worry about layering or nutrient balance. She has done only woodchips and only crop residue batches. Meredith is curious about adding rock dust directly to the compost, as opposed to spreading it on the fields directly, and what the effects may be. Compost is less about putting nutrients on the soil than it is about adding life — Meredith really believes in not turning compost for that reason.

 

Want to learn more about soil? Check out Meredith’s recommended reading list:

 

• The Ideal Soil book talks about the Albrecht method.
• The Biological Farmer by Gary Zimmer.
• Hands on Agronomy by Neil Kinsey.
• Knotts Vegetable Growers Handbook will tell you for each plant how much NPK they uptake per season.
• Southeastern Vegetable Extension Network puts out an annual vegetable growers guide, especially demands for NPK & Boron.
• Carbon Farming Solutions

 

Explanation of Handout

This is where Meredith’s nerdiness came out; I hope we captured everything accurately. Please note we’re having difficulty actually uploading the handout, so check back later for the upload.

Here is the handout that Meredith provided us to be used to calculate mineral needs/acre in order to remineralize your soil.

You can figure out the disparity between what your test says and what the ideal is, and then use this chart to apply amendments. Compare your soil vs. target amount. Mostly it’s to be used for annual vegetables. But, if you have a perennial system, all soils have been declining in mineral deficiency for a long time. This chart is very helpful in micronutrients especially. The parts per acre (PPA) = PPM (parts per million)x2; the target amount is the max you want to apply. Living Web Farms has a recording of Dan Kittredge giving a class on how to use this sheet. Skip to the end if you don’t want to hear the whole lecture.

Have questions about WNC CRAFT or about this article? Please email Sera Deva at farmer-programs@organicgrowersschool.org