1. The unknown ecosystem

2.  What is soil? What is it made of? Where do we get if from? What is your “definition” of soil

3.  The number of organisms in one shovelful of soil  The number of humans on earth

4.  More in one shovelful than all the humans that have ever lived on earth  Many don’t even have names yet

5.  Start with minerals  Add organic materials (humus)  Water  Air A Recipe for Soil

6.  It takes 100 to 100,000 years to form one meter of soil  Soil forms by weathering and decomposition.  Faster in warmer climates  Why?

7.  Mineral (weathered rock) = 45%  Air = 25%  Water = 25%  Organic matter (humus) = 5%

8.  Dark organic matter from decomposed plants and animals  Provides nutrients for crops  Soil organisms feed on it  Absorbs and holds water

9.  1000 fit on the head of a pin.  Divide to reproduce every 20 minutes.

10.  Arachnids  No eyes (it’s dark in the soil)  Eat only fungus

11.  Also called round worms  Only 1 mm long  Some eat bacteria, some eat detritus, some eat fungus

12.  Live 3 to 6 years  Eat detritus, also swallow soil  Add bacteria back to soil

13. Tardigrade

14.  https://www.youtub e.com/watch?v=Vu Hznslr8aI https://www.youtub e.com/watch?v=Vu Hznslr8aI  https://www.youtub e.com/watch?v=YF8 OJt_pujc https://www.youtub e.com/watch?v=YF8 OJt_pujc  https://www.youtub e.com/watch?v=cjV 2WP0wkvo https://www.youtub e.com/watch?v=cjV 2WP0wkvo

15. The texture is caused by the size of the soil particles

16.  Sand – Between 0.06-2.0 mm in size  Sandy soil drains quickly so roots can penetrate. Too much sand in a soil does not hold enough water and nutrients for most plants.  Does not shrink or swell so it makes a good foundation for buildings.

17.  Silt – Between.002-.05mm in size.  Silt allows for air to circulate but still retains some water.  Silty soils do not usually hold enough water for most plants.

18.  Clay - <.002 mm in size. Water clings to tiny particles holding larger soil particles together forming clumps called aggregates.  Aggregates like gravel provide drainage channels for water. Water will not drain in soils with a lot of clay.  Clay is easily compacted, crushing air and water pore space. Plants root cannot penetrate through dense clay soils.  Clay is a poor material to build on because it swells with water.

19.  Loam is soil with a mixture of sand, silt and clay. It is the best type of soil for most crops