Soil on Earth

Write five things that comes to mind when you hear the word “soil”.

WARM UP

What is Soil?

Soil is a mixture of minerals, organic material, air, water, and

microorganisms.

Soil Composition

• 45% are minerals. Soils lose minerals by erosion, leaching (the movement of minerals dissolved in water), and by plant uptake.

• 5% is organic matter. Organic matter is matter composed of decayed remains of living organisms, leaves, roots, insects... It is also called humus and is the glue that holds mineral particles together, helps form pore spaces, and increases fertility of the soil.

• 25% is air. Fertile soil also needs to contain air. Air in soil similar to air in atmosphere and oxygen is especially important; turning and mixing soil called tilling and this is how air is introduced to the soil.

• 25% is water (soil moisture).

Earth Soil Composition

Mars Soil Composition

Mineral MatterOxygen55%

45%

Data taken at the Viking 1 landing site: http://resources.yesican-science.ca/trek/mars2/final2/mars_info/mars_info_soil.html

https://www.youtube.com/watch?v=60KBrOFQrTA

https://www.youtube.com/watch?v=7koIlNPay-s

http://www.iflscience.com/space/what-did-mars-look-when-it-had-water

Soil Moisture

• Soli moisture is water held in soil pores.

• If soil contains too much water, it becomes saturated.

• Optimum water content is field capacity

(water to air ratio = 50% to 50%).

• When soil moisture is gone - wilting point.

Soil Moisture

Three States of Moisture in Pores

Soil Organisms

• Earthworms mix and aerate the soil.• Bacteria help add nitrogen to the soil by converting

atmospheric nitrogen to plant-available forms such as nitrates.

• Fungi and insects improve structure and add organic matter.

• Rodents help to mix the soil.

Soil Structure

• Soil structure is the arrangement of mineral particles and organic matter within a soil.

• The parts of a soil are sand, silt, and clay.• If a soil is high in sand – the soil will have

excessive drainage.• If soil is high in clays, it prevents water

infiltration, is highly erodible, and does not support crop growth.

http://www.google.com/url?sa=i&rct=j&q=&esrc=s&frm=1&source=images&cd=&cad=rja&docid=Mg_JSRS2MjrcyM&tbnid=6nP7bxlBElMbDM:&ved=0CAUQjRw&url=http://techalive.mtu.edu/meec/module06/SoilClassification.htm&ei=k0z4Uen_AaThyQH_2YGwDg&bvm=bv.49967636,d.cGE&psig=AFQjCNGZKjpT81pk0boLq0TkpA7L6So8Og&ust=1375313129570131

http://www.google.com/url?sa=i&rct=j&q=&esrc=s&frm=1&source=images&cd=&cad=rja&docid=5ktxrxgljr8AfM&tbnid=_KobHw3mH0X0FM:&ved=0CAUQjRw&url=http://passel.unl.edu/pages/informationmodule.php?idinformationmodule=1130447039&topicorder=2&maxto=10&ei=AU34UcTbOqTqyQH494HoAQ&bvm=bv.49967636,d.aWc&psig=AFQjCNFh7tjb-RBeq76e2PVQNiwAz0Mn3A&ust=1375313528479451

Next Steps…

• Why is it important for us to understand the soil on Earth before we go to Mars?

• The rest of the week we will look at both Earth and Martian Soil.

SOIL TEXTURE TRIANGLE

SOIL TEXTURE TRIANGLE ACTIVITY

60% Sand30% Silt10% Clay

1. WHICH SOIL TYPE CONTAINS 60% SAND, 30% SILT and 10% CLAY?

SOIL TEXTURE TRIANGLE

60% Sand

SOIL TEXTURE TRIANGLE

60% Sand30% Silt

SOIL TEXTURE TRIANGLE

60% Sand30% Silt10% Clay

IT IS SANDY LOAM!!!

SOIL TEXTURE TRIANGLE

60% Sand30% Silt10% Clay