Soils Exam 3 Flashcards
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What happens as the biomass of organisms goes down?
The abundance of them goes up
Functional Diversity
Utilize a wide variety of substrates and carry out many processes
Functional Redundancy
Multiplke species being able to carry out the same function
Ecosystem stabability
Soil having several ways to accomplish the same function BY FUNCTIONAL REDUNDANCY
Macroorganisms
Greather than 2mm
Mesoorgannisms
2-.1mm
Microorganisms
Less than .1mm
Annelids
Earthworms
Helminths
Nematodes
Largets biomass in soil
Fungi
Actinomcytes
Long strainds and function like fungi but relates to bacteria
Protozoa
Mobile single celled and karger than bacteria
What is a midden and its function
An eathworm cast that improves soil physical properties
What microorganism helps soil horizontally
Ants
What helps soil veritcally
Termites
H?ow do nematodes benefit and harm soil
They release N from bacteria, but they also bite plant roots to infection
What is the function of Protozoa?
They eat Bacteria to release nutrientrs
What are the 3 broad groups of fungi?
Yeast Mold Mushroom
What separates bacteria from fungi and actinomycetes
Bacteria breaks down material in more anaerobic environments and less complex ,molecules
Whyat is a commonesalist
Organisms living side by side with little interaction
What decomposes the most complex organic matter?
Actinomycetes
What happens to the organic matter during composition
2/3 goes into c02 and 1/3 becomes microbial cells or soil
What happens at a high c/n ratio
immobilization
What happens at a low c/n ratio
Mineralization
What two things does SOM do to improve soil
Increases CEC and pH buffering
What 3 residue properties affect decomposition?
Size and surface area
C/n ratio
Chemical composition (lgnin..)
For which 2 nutrients are soil tests done?
P and K
Ammonia to ammonium
Volizalization
What does soil managemenr affect the most
water
what nutrient are freshwater systems limited by
p
what nutrient are saline water systems limited by
n
Name 4 ways to limit nutrient lose in agri
buffer strips
cover crops
conservation tillage
forest stand management
soil minerals supply little amount of this nutrient
N
What ratio is higher in manure than plant tissue
P:N
what 4 factors influence mineralization
moisture
aeration
temperature
C:N rstio
where does the majority of po and k come from?
geologic deposits
where can k fert be found
salt beds
from where is n fertilizer extracted
the atmosphere via the haber bosch process
what are 3 hazards associated with inorganic fert use
salt hazards, acid formation, volatilization
how do you know how much n to add to soil
expected crop yield, soil type
what does freeze/thaw affect in soil
k availability
what is the first step of mineralization
ammonification
what is the second step of mineralization
nitrfication
What does a high C:N ratio cause GREATER THAN 30:1
immobilization
what does low C:N cause LESS THAN 20:1
mineralization
What can caude volitalizarion?
high pH
little moisture
is nitrate readily leached
yes?
what is the reduction ofn to a gaseous form
denirtification
what occurs to nirtogen in anaerobic conditions
denitrification
what can cause redness and short roots
P deficiency
what major nutrient is scarce in soil
P
what helps plants uptake p
mycorrhizae
what happens when C:P ratios are less than 200:1
mineralization
what happens when P concentration is greater than 300:1
immobilization
what type of p is unavailable as pH increases
calcium phosphates
what type of p is less soluble at lo pH
hydroxy phosphates
where is most k held in soils
feldspars and micas that make it unavailable
what is throughfall
k taken up by plants then washed away by raineater from plant foliage
what is the problem with k
there is a large amount present, but only little available and plants intake it luxuriously
what nutrient is measured by its rate of transformation than total amount in soil
K
how do we limit k uptake in plants
watch the soil pH levels
what organism has greatest biomass in soil
fungi
what is the smallest pool of P
soil solution
what are the 2 most common ways to lose SOM
erosion and decomp
what organism ahs the greatest number in soil
bacteria
what 3 propeties affect decomp
chemical content, zie, C:N ratio
what process adds most nitrogen to soil
biological nitrogen fixation
what is the symbiotic relationship between roots and fungi
mycorhizzae