Unit 7 Soil Notes

Week 7 noteseses



MAnaging Alaskas Soils – CES

Organic soils bind minerals and increase water holding capacity, hold many minerals, including, N, P, S, Mo, Cu, Zn, Bn.  Makes up  about 10% of soil (THIS IS VERY GENERAL!)

Mineral soils, Clay is the smallest, Silt next, then Sand, then gravel.

Jeff Lowenfells talked about compost tea.  A faster method than soaking is to bubble you compost.  the air bubbles break the micro organisms free from the compost so they can go into the garden.

Air and Water are about 25%

Soil Texture is based on the percentages of sand silt and clay, and is static (except when you ad things)

Soil structure is the actual layout of the soil and can be changed.

“What falls from the plant to the ground is supposed to be there”

Permeability, Bulk Density,

pH – Can be increase by addiing, sodium, Mg, Ca, and potasstium, or lime.

Cation Exchange Capacity – ability to hold nutrients

Top 3 NPK, next 3 Ca,Mg,S, micros: B,Cl,Cu,Mn,Mo,Ni,Zn

N – very soluble, add in spring, not fallP – not that soluble.  In volcanic soils can get bound up.  Best with lots of organics or added in specific locations as needed.

K – Not too soluble, but needs moisture

Ca- Comes through lime or other source, plat availability can get messed up if dry.

Mg – not available in acidic soils.  If liming, make sure some Mg is in it or use in fertilizer.  competes with K,

Sulfur comes from organic material, fertilizer or gypsum.  Pungent plants require a lot

Mn, Zn,Fe,Cu have similar traits.  they are less available at high-PH, so either reduce pH or add chelated minerals.  All micronutrients can be sprayed on, but this doesn’t help with the soil problem.


ID of plant nutrient deficiencies.

Plants need three things to take up nutrients – soil must be moist, the pH needs to be in the right range, and the temperature must be right.

To determine deficiencies: Know what the healthy plant looks like, determine where symptoms appear, identify patterns of symptoms.


Soil is in the recycling business- plants grow from soil, soil breaks down decaying plants and animals and feed them to plants

Recycling rates are affected by temperature.  90% nutrients are in the soil in cool climates (organic layers mostly) and 70% is in the biomass in the tropics.

Need to design healthy habitats for soil organisms to function at their best.

An interesting flux between aerobic and anaerobic bacteria takes place, one increases while the other decrease and back an forth, based on oxygen availability and ethylene production.  In absence of ethylene aerobic go crazy and break everything down.  This happens in agriculture b/c of heavy soil aeration.

micro-sites are produced by roots giving off some carbon.  the microorganisms come in and do their thing right there, where it counts the most.

Agriculture F’ed this all up so what can we do to fix it (or not break it as the case may be):

Return organics to the soil (surface not buried), mulch and cover crop (with some ethylene precursors), cut don’t pull weeds, keep things in the soil (I’m going to do this with our legumes), don’t till, if you add N add it as ammonium,  add N when it is in high demand, add some low N mulch with it (such as cut grass) to absorb and store it, then the microorganisms will eat it then release it as they die.  Don’t overuse legumes, mix natives with exotics,

Soil quality – Iowa State

What’s the diff between agricultural crop and a horticultural crop.  MUST rotate!  Shit and lime is all you get to feed your plants.  In addition to manure fish emulsion and seaweed are popular.

Soil organic matter, important. crop rotation important b/c fix nitrogen and recycle other nutrients like P and K.   Deep rooted crops bring nutrients back up from the deep.

NRCS info –

Soil organisms are essential.  They break down complex organics,  nutrients and pollutants;  fix and make N available, improve soil aggregation and porosity, and feed on pests.

The soil food web, pants, algae etc get energy from the sun.  As parts of these photosynthetic species decompose, soil organisms break them down into components used for the plants,etc.  Starts with the little guys, who are eaten by the bigger guys, who are eaten by the bigger guys…

Organic matter has two parts, active and hummus.  organisms use the active part, bacteria the simple parts, fungi the more complex.

Food web complexity is important and can be enhanced by diverse habitats.


Bacteria: nutrient cycling, decomposition, water retention, disease suppression, millions per teaspoon, ton per acre

Fungi,:  nutrient cycling, decomposition, water retention, disease suppression; Decomposers, mutualists, pathogens (saprophytes);

Protozoa: A few times larger than bacteria, 3 types, Ciliate, Amoeba, Flagellate;  They eat bacteria and release nitrogen and other nutrients, also regulate bacteria populations by increasing growth of some and not others. , they are a food source for other organisms

Nematodes- compete with protozoa, one or the other is usually around.  unsegmented tiny worms, some eat bacteria or fungi or smaller nematodes or a mix; Nutrient cycling, grazing, disperse microbes bc they can move around, feed others, and can cause or prevent diseases.

Arthropods – little bugs with jointed legs.  Shredders, predators, herbivores, and fungal feeders;  Shred plant material making it more available to others, move microbes, mineralize nutrients, enhance soil aggregation, control pests.

Earthworms: Not required but evident of a healthy system.  Cycle nutrients, affect water movement and soil structure, and plant growth.  They carry organics into the soil, make water and root pathways,


CES – Compopsting – Hot cold and worm, Hot is best.  turn often and keep moist.  25:1 C:N ratio

Nuiqsiut composting.  Gathering 100 families waste into a giant pile.  Covering it and wha-la

Why compost – puts the good micro and macro organisms back into the soil and gives them food.

Elaine Ingrahm – talking about compost in soil.  Organisms don’t move with water, need to be taxi cabbed around.   that’s why compost tea is so effective.  It make the organisms penetrate deeper.  Have to put tea on several times.

Worms and heat kill the mychorrizal fungi so have to add back to compost.  On bad soil, plant directly into compost inoculated with mychorrizae.  Strat then transplant into garden.

Elaine Ingham, Soil Food Web –

Importance of not disturbing soil food webs and compacting soils.  Low till or no till.

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