UWUW C. Henry Soil basics! The excited skin of the earth! Physical components Chemical processes Biological processes Chuck Henry

UWUW C. Henry Ecological Restoration Handbook By: Chuck Henry & Elena Olsen Chapter 2 from:

UWUW C. Henry Proportions of the physical parts of soil

UWUW C. Henry Relative sizes of the three mineral soil particles Gravels and rocks (mineral particles > 2 mm do not count as soil to a soil scientist! They just take up space!

UWUW C. Henry Sand Relatively big and not very reactive Water passes through sand quickly Doesn’t hold on to nutrients very well

UWUW C. Henry Silt In size, between clay and sand Can hold some water, can hold some nutrients Can erode!

UWUW C. Henry Clay Almost the opposite of sand Very small Holds water very tightly Very sticky!

UWUW C. Henry Mixtures of particles If you have just the right amount of each type or soil particle –the best characteristics of each one blend to make a really good soil Best soils: –loams

UWUW C. Henry “the fuel that runs the soils engine!” And then… organic matter! Holds and also releases water Holds and also releases nutrients Energy for healthy microbial populations

UWUW C. Henry The other half of soil: pore space! air water Where water and air is held Where roots grow Macropores –Water drains Micropores –Hold water

UWUW C. Henry Soil forms in layers called horizons All the soil horizons make a soil profile

UWUW C. Henry Soil forming factors make soil the way it is Parent material –The original mineral particles Time –How long processes have been working Climate –Precipitation and rainfall Biota –Plants and animals living on the soil Topography –Slope, depressions, ridges, etc.

UWUW C. Henry Local soils around Western Washington Till Outwash Lacustrine Alluvial Organic/mucK Residual

UWUW C. Henry Till Ablation till –Loose, unsorted over Basal till –Highly compacted

UWUW C. Henry Outwash Coarse material Left from water rushing off glaciers

UWUW C. Henry Lacustrine Clay deposited in lakes

UWUW C. Henry Alluvial Particles sorted by rivers

UWUW C. Henry Organic/muck Forms in bogs Dead plant parts

UWUW C. Henry Residual Decomposed rock –Volcanic –Sedimentary –Metamorphic