Soil: So much to learn

Educational YouTube videos and Instagram posts by topic

Updated: 26 March 2025


Soils from Clarendon, TX, Snyder, OK and Santa Rosa, NM


Soil physical properties

The Munsell system is used to describe soil colors based on its hue, value and chroma.
Soil texture is the relative amount of sand, silt and clay. This triangle shows the soil textural classes.

The Sponge Model of Soil: Soil Water

Soil horizons in a soil profile: What’s the story? by Dr. Dirt

Soil chemical properties

Soil is an environmental filter with three modes of action: physical, chemical and biological.
Negatively charged clay particles attracted to the electrode connected to the anode (positive pole of the battery).
  • Carbonate reaction
  • Electrical Conductivity: Water, Salt, Lighty (YouTube, 36 seconds)
    • Electrical conductivity is used to diagnose soil salinity
  • Redoximorphic features (RMF) – fluctuating water tables create alternating aerobic and anaerobic conditions that result in some reduced iron and manganese and, in some cases, their subsuequent loss (dull colors) and some oxidized iron and manganese (bright colors) – as in the story of the aggregateon the home page.
    • RMF (YouTube, 26 sec)
    • RMF (YouTube, 31 sec)

Soil Fertility

Plant essential nutrients on the Periodic Table of the elements
Organisms grow in response to the most limiting factor: Those supplied by soil, air and water are listed from most limiting (bottom) to least (top)

Biology: Soil is alive

Temperature affects microbial activity and gas volume. The balloon filled with CO2 in four days due to microbial respiration. The volume of gas decreases with temperature, so why is the balloon inflated in a frozen soil?

Updated: 26 March 2025