CH37: Soil and Plant Nutrition Flashcards
Main functions of nitrogen in plants?
N is a component of DNA and RNA; proteins; and chlorophyll
Main functions of phosphorus in plants?
P is a component of DNA and RNA; ATP; and membrane phospholipids.
Main functions of potassium in plants?
K is an enzyme cofactor and plays a role in maintaining tugor pressure.
96% of the dry mass of plants is composed of:
Carbon, Hydrogen, Oxygen
How many essential elements in most vascular plants?
17
Who discovered that most plant mass does not come from soil?
Jean-Baptiste Van Helmont
A Horizon contains:
Mineral particles, living organisms, humus
Differences in B Horizon compared to A Horizon?
B horizon has limited organic matter and is less weathered.
C Horizon is made of:
Mainly broken down rock without much else.
Which processes turn rock into soil?
Freezing waters, chemical breakdown, and composition.
Rank soil particle sizes from largest to smallest:
Sand > Silt > Clay = Loamy Soil
What is humus?
Decaying organic matter
What are the benefit of humus?
1) Prevents clay particles from packing, forming crumbly soil which retains water and allows root aeration. 2) Increases cation exchange capacity (due to increased water). 3) Provides reservoir of nutrients through decomposition.
Types of organisms typically found in topsoil?
Bacteria, fungi, algae and other protists, insects, earthworms, nematodes, and plant roots.
What effects do organisms in topsoil have on the soil? (What types of properties are altered?)
Physical and chemical properties.
