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Soil Science Final
Terms in this set (54)
What horizon is characterized by an accumlation (illuvation) of silicate clays?
soils Separates used to determine soil texture are?
Which master horizons is Characterized by eluvation of material?
Soil color is an indicator of things that have happened in the past. When the soils has a region of grays soils present, it indicates that
the soil has been reduced(wet) at some point
Blocky structure is most often in found in what horizon
Two most common igneous rocks that form into a soil are
granite and basalt
The parent material of a soil formed in a flood plain is most likely
If you have an igneous rock that is light in color and weight, what can you tell me in relation to the soil that would form from its weathering?
it is acidic, and low in nutrients
which of the the following both contain a chemical and physical weathering process?
dissolution and abrasion
What substance acts like glue when soil structure is being formed?
Cultivation of soil alters water-stable aggregates. As a a result _____?
runoff will increase
it can be assumed that the particle density for most soils is approximately
2.65 g cm -3
When building a house, you want to ?
decrease pore space, and increase bulk density
As the bulk density increases
the total poor volume decreases
why is the bulk density of most soils 1.33 g cm -3?
Half of the volume are pores
General rule, the bulk density in a profile
will increase with increasing depth because of the increasing pressure from the weight above and decreasing of soil organic matter
Which soil colloid has the greatest amount of cation exchange capacity
Which of the following colloid are considered to be 2:1 mineral
illite, montmorillonite, vermiculite
Which of the following colloids has a permanent charge?
if you were going to make a pot which type of silicate clay would you use?
Which soil order would you expect to have the greatest CEC?
as surfaces area increases, CEC
Four general catagories of Colliods
allaphane, Humus, Fe&Al oxides, silicate clays
Which soil condition contains the maximum amount of water?
Which soil texture would typically have the greatest amount of plant nutrients available
What property of a water molecule has the most significant influence on the forces of adhesion and cohesion?
Plant available water (PAW) is held in the soil between what moisture potentials
-33 to -1500 kPA
Water moves based on
energy potential high to low
Most water uptake by plants
What is the best way to water your lawn?
Water less often for long periods of time
Which soil texture would have the highest rate of saturation flow?
The air in the atmosphere has ______ than the soil air.
more O2 and less CO2
The difference in air composition for the atmosphere and soil is due to
the majority of gas interchange is achieved through which mechanism
Which indicators must be present for a soil to be considered a wetland?
Hydric soils, Hydrophytic plants, long periods of inundation
Why can Specific heat of soil minerals be estimated at 0.2 cam g c-1
most soil minerals are composed of similar mineral compositions
Approximately what percent of solar radiation absorbed by the soil is used to warm it
Dry soils heat faster than moist soils because
water has a higher specific heat than soil
What are the base cations in lime that we have to apply to the raise the Ph of a soil
Magnesium and calcium
Which organic matter breaks down the slowest?
Water is/are the major causes of soil acidity
Rain, nitrogen fertilizers, high yielding crops, atmospheric condtions
a mole burrowing in the soil is an example of
why does tillage decrease the amount of soil organic matter?
it increases the rate of microbial respiration
Most nitrogen lost from the soil by leaching occurs in the form of
Fixation of nitrogen occurs from
conversion of atmosphic N to soil N
Which of the following plants symbiotically fix nitrogen?
additions of nitrogen cause
increase microbial acitivity
Why is water one of the main culprits of nitrogen loss in soil
nitrogen binds tightly with water, and moves where it goes
Most nitrogen lost from the soil by volatillzation occurs in the form
NH4 to No3-N
No3-N to a N2 gas
Major losses of nitrogen through volatillzation occurs under what conditions when applying fertilizer
Windy conditions, Hot temperatures, High soil PH
What is the controlling factor for phosphorus availability in the soil
Phosphorus lost by runoff is very small compared to the amount of runoff lost by
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