Equiosity Podcast Episode 79: Manda Scott Pt 3: Soil Farming, Horse Welfare, and the Link to Training

 

Before I jump into what this means for our horses, I just published Part 3 of our interview with Manda Scott. We pick up where we left off with a discussion of regenerative farming and the connection to both the health of our horses and of the planet. We address the question of what to do with our manure piles and how to get more organic matter into our soils. And that in turn takes us straight to a discussion of this week’s Planet Project: the water infiltration test.

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I’ll share with you some of what I have been learning from Gabe Brown’s book “Dirt to Soil”. Brown describes his journey from commercial agriculture (what he was taught in Ag college) to regenerative farming.

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He summarizes his recommendations in the Five Principles of Soil Health. He would say these are principles developed by nature. When you learn to follow them, your land can thrive.

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Principle 1: Limit Disturbance

He is referring here to tilling the soil to prepare it for crops. Even if all we have is a small vegetable garden, often we begin by tilling the soil. We’ve been taught that tilling improves the soil when in fact it is the opposite. Tilling, according to Brown (or he would say nature), breaks down soil structure.

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From Dirt to Soil:

“It destroys soil aggregates, significantly decreases water infiltration rates, and accelerates the breakdown of organic matter, among other effects. During this intrusive process oxygen is infused into the soil, which stimulates particular types of opportunistic bacteria that quickly multiply and consume the highly carbon-based biotic glues.

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These highly complex natural glue substances hold the micro and macro aggregates (composed of sand, silt and clay particles) together. When the glues are gone, the silt and clay particles fill the voids, which reduces porosity.

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This reduction results in anaerobic conditions in the soil, altering the type of soil biota, which in turn may lead to an increase in pathogens and loss of nitrogen in the system because of an increase in denitrifying bacteria.

Carbon dioxide is released into the atmosphere. As microbes die, they release they release soluble forms of nitrate nitrogen into the soil solution which stimulates weed growth.

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Tillage also diminishes complex mycorrhizal fungal networks. The severed hyphal network can no longer deliver complex amino acids and other complex organic/inorganic molecules, thus impacting plants and animals. Fewer nutrients for plants means fewer nutrients for animals.

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This is the main reason the soils on my ranch saw organic matter levels drop from an estimated over 7 percent pre-European settlement to less than 2 percent at the time we purchased the land. Consider that organic matter (carbon) controls 90% of soil functions related to plant growth, and you understand why tillage is so destructive.” (excerpt from Dirt to Soil).

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Now none of us are tilling our horse pastures, but some of the mud lots I see in my area are victims of the same effect. Too many horses on too small a space break down the protective barrier of sod and churn the soil into knee-deep muck. Especially when they are on clay, the soil structure breaks down. The water can no longer be absorbed. The horses are squeezed into smaller and smaller spaces as they try to avoid ever-expanding pools of standing water.

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This week I had you do a water absorption test. Brown talks about the change in his land’s ability to absorb water. In the water absorption test you are looking at the rate at “which rainfall can infiltrate our soils rather than ponding on the surface and evaporating or exiting as sheet flow.”

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Here’s another short excerpt from his book:

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“Our decision to stop using synthetic fertilizers on the ranch was a big step on our journey into regenerative agriculture. It was easy at that point to see the difference between our soil and our farming neighbors, including an organic producer. Their croplands clearly lacked organic matter and soil structure. The water infiltration rate on our farm had increased significantly. In 1991 the rate was one-half inch per hour. In 2015 it was one inch of water in nine seconds. A second inch will infiltrate in sixteen seconds. That’s two inches in twenty-five seconds!

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That’s the power of mycorrhizal fungi and soil biology. They combine to build soil aggregates, which allows water to infiltrate, and then the organic matter stores that water. It’s not a matter of how much total rain falls on your land, it’s how much can infiltrate your soils and be stored there that counts. That storage ability is the effective total rainfall. If we have low amounts of effective total rainfall, we create our own drought.” (And we also create flooding into the areas where the rain runs off instead of being absorbed into the soil.)

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I tested three areas at the barn. I used a 2 inch cylinder and timed how long it took for 2 ounces of water to be absorbed.

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In my upper pasture which is a clay soil it took 3 minutes 11 seconds. On a hillside where I have put a combination of shavings and horse manure it took 1 minute 15 seconds. In the garden by the driveway where I have used my premium compost from the horses it took 9 seconds! That’s quite a difference!

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So limit disturbance is Principle #1. I’ll share the other four principles in the weeks to come.

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For now look at your land. Are there areas where your horses have “tilled” your soil? How can you turn things around and transform mud lots into good grazing? That’s the question we’ll be exploring in the weeks ahead.

As a sneak preview next week we’ll be recording a podcast with Jane Myers, the developer of the equicentral system. This week she shared a video in the Horses for Future facebook page on using hay mulch to restore areas that have been broken down and damaged by over-grazing. I thought that was perfect timing given this week’s Planet Project.

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