Foundation Courses, Notes for Chapter 2 Lecture 7 – Compaction & Anaerobic Conditions

7 months ago (Edited)

Notes for Chapter 2 Lecture 7 – Compaction & Anaerobic Conditions

This lecture explains why BLACK compost is not a good thing. This lecture also goes over why having a healthy rhizosphere will mean that pH meters for your soil is not a recommended to use when growing in a living soil.

Since @peakd put the youtube video as my thumbnail on the last post despite selecting my quiz picture as the first picture to use, I will insert my quiz results first. In which I will also share the picture of the one question I got wrong that I challenged. It is pretty funny.

Elaine does talk about how a collapse of biology will cause compaction. I will hopefully, get a clarification on the matter above sooner than later via email.

Ok, well I will share this video first which is not about cannabis, like usual but rather about compaction which is what this lecture was mostly about. There is a reason why you will not find a youtube video for soil food web people, at least easily, about using pH meters in the soil. Your soil biology/rhizosphere will balance the pH in your soil out with out the need of pH meters. This is talked about in the post below.

Nutrient Cycling

Nutrient Cycling happens when plants produce exudates (Simple sugars mostly, some carbohydrates and proteins) and 30-40% is allocated into the root system from the photosynthesis process. The exudates feed the fungi and bacteria whom will then break down parent soil material into nutrients. Predators eat bacteria and fungi and release nutrients from bacteria and fungi into plant available (soluble) nutrients from their poop/waste.

Healthy Soil Food Web

A healthy soil food web will make nutrients at rates that the plant will require leading to optimal flavor and beneficial nutrition levels for humans and animals. Water run off and leaching will stop and result in the soil retaining the nutrients in the soil. Soil structure naturally happens and toxins are decomposed as well.

What really hold nutrients?

An experiment by Elaine where Sandy loam soil with no organic matter was repacked to the same density and Calcium (Oyster Shell) was the nutrient chosen to see where the nutrients were retained. 300 micrograms of Ca leached into soil by passing 1 litter of water through it. Four different containers had different variables added to them.

Just Parent Material
- More calcium than water was lost through leeching. 100% Ca lost

Parent Material + 5% Organic matter
- 98% of the Ca lost

Parent Material + 5% Organic matter + Bacteria
- 95% of Calcium was lost

Parent Material + 5% Organic matter + Bacteria + Fungi
- 0% of Ca lost

Why does Bacteria and Fungi do not get washed away?

Bacteria and fungi makes glues. Bacteria makes the most glues. Soil

Will Soil organisms affect pH and Cation Exchange Capacity?

Yes they will. Bacteria will create alkaline glues. Will make minerals more bioavailable in alkaline conditions. Fungi make organic acids and make minerals more bioavailable available in acid conditions. The exudates from the plant roots in the soil will determine who (Bacteria or fungi) to feed and where in the rhizosphere/ root area. pH is regulated by a healthy Rhizosphere and the plant's pH needs are met as a result of the exudates that it excretes and the types of fungi and bacteria that it feeds.

Bacteria and fungi will be more concentrated in Nitrogen, Phosphorus, Sulfur, or potassium, etc. than any other micro-organism. They can not release nutrients unless they are eaten by a higher level predator.

Insoluble chemical salt forms of nutrients are the most leachable forms of Nitrogen. Nitrate is least leachable form of salt vs Ammonium. In order from least leachable to most leachable organic forms of N that are both anerobic and aerobic is: Bacteria, Fungi, Protozoa, Nematodes, Micro-arthropods, Roots and Organic Matter.

Compaction

Effects on roots

Roots grow sideways
Salt layer accumulation happens from inorganic fertilizers. Evaporation happens and increases salt layer on surface.

Causes of compaction

Rainfall on bare is a very bad thing. Soil needs protection from the pressure of each rain drop. Plant cover or mulch is desirable. Heavy equipment and tillage will increase compaction. A lack of biology and toxic chemicals will cause compaction.

How does compaction affect plants?

Plant roots will not grow deep into the soil and they will have no structure. There will also be a lack of oxygen which will result in toxic plant compounds. Pests and disease will happen.

What happens when soil compaction occurs?

Aerobic organisms will die or go dormant. Since Soil Structure is lost compaction will increase.
Loss of N, S, and P as gasses will occur as well as leeching and erosion.

Anaerobic Conditions in a compost pile

Lack of oxygen in a compost pile will create a white ashy looking (actinobacteria). After the actinobacteria is done making enzymes a dark black color to the compost will happen underneath the actinobacteria layer. This resulting black anaerobic compost. This is all bad.

When you are told that you need to add lime or gypsum to a soil due to low ph it is because loss of soil biology. Each year you will be told that you need to keep adding lime each year. Compaction layers will form each year.

Predominate N form in soil

Aerobic	Anaerobic
Organic matter	Remains as organisms
Nitate	ammonia
nitrite	ammonia
ammonium	ammonia
Oxidized	Reduced

Ammonia leaves black color

Predominate S form in soil

Aerobic	Anaerobic
Organic matter	Remains as organisms
Sulfate	Hydrogen Sulphide
Sulfite	Hydrogen Sulphide
Sulfur dioxide	Hydrogen Sulphide	-
Elemental S	Hydrogen Sulphide
Oxidized	Reduced

Predominate P form in soil

Aerobic	Anaerobic
Organic matter	Remains as organisms
Rock P	Phosphine gas
PO4	Phosphine gas
Sulfur dioxide	Phosphine gas
Oxidized	Reduced

Anaerobic Organic Acids

Only produced under anaerobic conditions, smells can indicate conditions.

Acetic acid
- Vinegar

Butyric Acic
- rotten milk

Valeric Acid
- vomit

Putrescine
- decaying flesh... like rotten meat.

Toxic Materials only produced in Anaerobic conditions

Alcohol
- 1 ppm alcohol solubilizes any plant cell wall
- anaerobic soil/compost produces 25 ppm alcohol
- Most toxic materials is alcohol. Will solubilize any plant cell wall
Formaldehyde
Phenols

Surface Compaction Caused by Rain

Unprotected soil surfaces means evaporation and salt accumulation which will form crusts. Soil organisms work to immobilize those salts instead and incorporates them into organic matter.