Notes for Ch. 1 Lecture 9: Soil Structure (Part 1)

---

Quiz results

---

Here is a video about soil structure from the future cannabis project!

---

Soil Structure

When we build soil structure we will increase water retention. Organic matter will hold 10x it's weight in water. But we need to have the pores and structure that will hold the organic matter and prevent it from flushing beyond the rooting depth of the plant. As structure is built we will have more nutrients. Organic matter will turn into hummus. Roots will grow deeper.

What is Soil structure?

Structure will first be built by structure. Without bacteria we will not be able to build the micro aggregates. Bacteria will glue themselves to the mineral particles and roots and be bound to the roots and mineral particles; Micro aggregates will form.

• Bacteria glues are largely alkaline. More space between minerals and organic matter is created when Bacterias form micro aggregates.

• Fungal Hypha will adhere to several micro aggregates and proceeds to pull them all together that will form macro aggregates. Macro aggregates will be visible with eyes.

• When macro aggregates are formed when then we are building the large spaces into the soil to allow for water, oxygen and roots to move through soil.

• Some spaces (pores) in the soil/macro aggregates will hold water

Anaerobic bacteria do not make glues that holds the parent materials and organic mater together.

When soil becomes less than 13% moisture than we start to lose water on the surfaces of the macro aggregates, micro aggregates and mineral particles.

Aggregates will be jagged

Bacterias will be smooth; shaped like rods and circular shaped

Amoebas like to be on surfaces of mineral particles/aggregates.

Stalked Ciliates indicate there is a lack of oxygen typically from so much microbial growth that can happen where oxygen is used up faster than the oxygen can be diffused into the water. We can have Micro-sites in good soil where anaerobic conditions happen due to a narrow pore in micro/macro aggregates. Diversity in these site with anaerobic conditions can be a good thing if in small numbers/quantity. Variability is a good thing in soil with good structure.

• In a well structured soil we will always have protected places for pray to avoid predators.

• Ciliates like to eat bacteria. But some time can get to beneficial bacterias because there will be protected places where pray organisms can hide from predators.

Flagellates can get to bacterias because it is as big as the bacterias.

Nematodes are like the big bad wolf to the amoebas and the amoebas are like the big bad wolf to the bacterias.

Larger predators(Arthopods, earthworms etc.) will create space in the Micro/macro aggregates, this will create more room for oxygen and water. More activity and life will happen.

Root hairs are single cells of the root system. Exudates are being released from root hairs.

• A Myco spore will be carried by the root hair into the soil. The plant root exudes an exudate to wake up the spore/organism. The spore will germinate and starts to grow. The fungus will follow the trail of exudates into the root then in-between the root cells into the infection site. A antibody/antigen reaction happens. The plant has to have the right type of receptors (lecithins) and the fungus has to have the opposite type of lechitins to allow for binding of the site. The fungus is then allowed to go through into the cell wall. An Arbuscule is formed, the place where the exchange of nutrients happens between the fungus and plant. The fungus sends message through hyphae to make the enzymes to pull the certain types of nutrients and water into the plant. The fungus then translocate the nutrients back into the root.

Mycorrhiza fungi delivers water, nutrients to the plant and the hyphae create macro aggregates.

Plant roots can only exert 150 psi in the soil. Tap roots can exert up to 300 psi in soil. If they have to push roots into soil unnecessarily then the plant will have a hard time growing.

• We want the Micro-organisms to travel to the compacted parts of the soil to form soil structure. They will travel down into the different Horizons of the soil with water.

Soil Horizons

• Organic Matter horizon 1

  • The bacteria and fungi start to colonize this layer. Also species from when on the plant leaf debris. They start to colonize when the plant debris falls to the ground.

• Organic matter horizon

  • Micro and macro aggregates are formed. Brown humus material (organic matter and Organisms).

• A Horizon

  • As time progresses, water and micro organisms move deeper into the soil. A horizon gets deeper over time.
    |
    etc.

Soil drainage

• The anaerobic compaction layer

Where water backs up. As The compacted zone where anaerobic layers exist becomes higher and higher in your soil horizons the root systems die off. The deeper the compaction layer the deeper the roots and as the compaction layer becomes higher and higher the root systems will become more shallow. Color of soil progressively turns black/gray with rusty colors ( light blue copper color in extreme conditions. Hydrites)

Water infiltration and structure

• Sandy soil

  • infiltration happens too quickly. There is no structure to hold the water and this results in high watering requirements. We want to add organic matter back into the soil. Too much space in sand.

• Clay soil

• Particles/ Parent material are too close together.

• Infiltration happens very slowly because there is no spaces for water. This results into anaerobic conditions. This results in anaerobic conditions typically.

  • Tilling is required, hopefully only one time, to put in organic matter.

(@dynamicrypto, So when you added all that organic matter initially in Vegas maybe that would had been enough but maybe not due to soil erosion from not having top cover i.e. mulch or cover crops. We still probably added too much organic matter/ compost the second time around.)

• Well structured soil

  • Infiltration happens slowly but still needs biology in the the organic matter to have proper nutrient cycling to happen every second of every day.

  • Reduced watering happens as a result.

Soil vs Dirt

• Soil

When the organisms build structure soil is created. The nutrients(parent mineral material) is held in soil. Water is then retained and moved more slowly through the soil. This results in clean water moving through the soil.

• Dirt

No organisms means dirt and no structure. The nutrients ( parent mineral material) move with the water. Water is not held in soil pores and moves rapidly through the soil. Leaching, erosion, and run-off are problems that occur.

The Global water cycle

• Water evaporates of the surfaces of the oceans, lakes, springs and the ground.

  • Soil surfaces should be covered with mulch or cover crops. The darker the surface the quicker evaporation happens.

• Transpiration happens from plants

• Condensation happens when there is a small particle allows the water to condense on a small particle. Micro-organisms are needed.

• Precipitation

  • soil biology is needed

• Infiltration

• Surface Run-off

  • Should not happen if soil biology is adding structure

• Oceans

  • Water storage in oceans from the ground water is moving into ocean. If water is constantly moving than aerobic conditions should persist.

  • If water is slowed down evaporation happens and nutrients are off gassed into atmosphere.

---

---

Be Part of the Soil-ution!

https://www.soilfoodweb.com/

---

How to develop knowledge and a career in regenerative agriculture with the Soil Food Web School!

From Dr. Elaine Ingham B.A. M.S. Ph.D

https://www.soilfoodweb.com/sfw-courses-overview/

https://www.soilfoodweb.com/about/

---

Consultant Kickstarter Bundle

I am doing the Consultant Kickstarter Bundle for The Soil Food Web School

• https://promo.soilfoodweb.com/jan2022-coupon-consultant/?_ga=2.263782793.488540762.1644553986-1606617666.1644553986

---

The First step is to Study the Science by taking the Foundation Courses:

https://www.soilfoodweb.com/foundation-courses-2/