Chapter 37 Flashcards
What elements does fertilizer often have?
Phosphorous, Nitrogen, Potassium
What does phosphorous do?
Part of DNA/RNA, ATP, phospholipids
What does Nitrogen do?
Forms DNA, proteins, chlorophyll
What does potassium do?
Cofactor for enzymes used throughout cell, major roll in maintaining turgor (H2O pressure)
Is soil made up of biotic or abiotic material?
It has components of both
Why is soil erosion so bad?
It can take centuries to form but only years to be destroyed
How does soil texture range?
Very coarse (sand)–> very fine (clay
What is humus? Where is it found?
Decomposing organic material that is part of the topsoil layer
What is topsoil? Why is it important?
Horizon/top layer of soil- plants depend on it
What are the layers of soil like?
Broken down rock, living/dead organisms
Much less organic matter, less weathered
Broken down rock
What are loams?
Most fertile topsoil, about equal amounts of sand, silt, and clay
What is in soil solution?
H2O and minerals
Where do roots absorb their nutrients?
Soil solution
What organisms are found in soil?
Fungi, algae, protists, insects, worms, plants
What does soil biodiversity determine for the soil?
pH and chemical properties
What are some common causes of reduced soil productivity?
Chemical contamination, mineral deficiencies, changes in pH, changes in salinity
What is sustainable agriculture?
Long-term practices that are environmentally safer
What are the benefits of irrigatin?
Increased crop yield, balances salt levels
What is fertilization?
The practice of recycling mineral nutrients
What is phytoremediation?
Using living plants to clean soil, air and water (EG nuclear radiation)
What are the essential comounds for plants?
Cellulose and starch
How many essential nutrients are there for plants? How many of each?
17, 9 macro, 8 microW
What contributes the most to plant growth and crop yields?
Nitrogen
LOOK AT MUTUALISM DIAGRAM
What is a mutualism?
An interaction between 2 species that benefits both
What are some expamples of mutualisms?
Ants defend plant from attack, plant provides food
Shrimp digs burrow where it and goby live, goby acts as lookout and shrimp is protected while goby has shelter
What is the rhizosphere?
Area around roots/in soil
Where can bacteria in rhizosphere live?
Free living in rhizosphere or as endophytes (in plants)
How do bacteria benefit as endophytes?
Get sugars, amino acids, organic acids from plant cells
How do plants benefit as endophytes?
Antibiotics, chemicals that stimulate plant growth
What helps determine the species composition of bacterial communties?
Whether it’s inside/outside the root and by soil type
Where is the role of bacteria important in plant nutrition?
The nitrogen cycle
Why do bacteria take up atmospheric nitrogen?
It isn’t usable to plants
What converts atmospheric nitrogen into a form that’s usable by plants?
Nitrogen fixing bacteria (Produce ammonium)
How can nitrogen already present in the soil be converted to a form usable by plants?
Decomposition by Ammonifying bacteria, (Produce ammonium)
What happens to ammonium in the soil?
Nitrifying bacteria convert it to nitrite, then nitrate, which either gets denitrified and released into the atmosphere as N2 or the NO3 gets absorbed into plant roots
