12/02/2025 16:17:10
Soils Exam 2
The equation for calculating pH is
pH = -log[H+]
Buffering capacity refers to a soil's
Resistance to change in pH when an acid or base is added
A soil has the following chemical properties: EC >4, pH <8.5, ESP >15. This soil
would be characterized as
Saline-sodic
A soil with a pH of 5.0 is _____ more acidic than a soil with a pH of 7
100x
What is NOT a source of H+ ions
Lime
3 pools of soil acidity
active, exchangeable, residual
In a Sandy soil, the residual activity would be ______ greater than the active acidity
1000x
Buffering capacity refers to a soil's
Resistance to change in pH when an acid or base is added
Sources of H+ ions
Carbonic Acid, Biological metabolism, Accumulation of OM, Nitrification, Sulfur
Oxidation, Acid Rain, Plant uptake of Cations
Active
H+ activity in soil
Neutralized w/ lime
Exchangeable
Soil Colloids
100x more lime than active acidity
Clayey soil - Residual acidity is ___________ > active acidity
50,000x to 100,000x
3 sources of pH dependent charge
Broken edges of clays, Al/Fe Oxides, Functional groups of OM
RNV
RNV%
(FF CCE) 100
Gypsum
TDS
EC
P = ET + SS + D
P = precipitation
ET = evapotranspiration
SS = Soil Storage
D = Discharge
Fate of precipitation and irrigation water
Interception, Infiltration, Runoff, Soil Storage, Enters Groundwater
Interception
Precipitation captured by the plant canopy and its subsequent return to the
atmosphere
3 components of interception
Soils Exam 2
The equation for calculating pH is
pH = -log[H+]
Buffering capacity refers to a soil's
Resistance to change in pH when an acid or base is added
A soil has the following chemical properties: EC >4, pH <8.5, ESP >15. This soil
would be characterized as
Saline-sodic
A soil with a pH of 5.0 is _____ more acidic than a soil with a pH of 7
100x
What is NOT a source of H+ ions
Lime
3 pools of soil acidity
active, exchangeable, residual
In a Sandy soil, the residual activity would be ______ greater than the active acidity
1000x
Buffering capacity refers to a soil's
Resistance to change in pH when an acid or base is added
Sources of H+ ions
Carbonic Acid, Biological metabolism, Accumulation of OM, Nitrification, Sulfur
Oxidation, Acid Rain, Plant uptake of Cations
Active
H+ activity in soil
Neutralized w/ lime
Exchangeable
Soil Colloids
100x more lime than active acidity
Clayey soil - Residual acidity is ___________ > active acidity
50,000x to 100,000x
3 sources of pH dependent charge
Broken edges of clays, Al/Fe Oxides, Functional groups of OM
RNV
RNV%
(FF CCE) 100
Gypsum
TDS
EC
P = ET + SS + D
P = precipitation
ET = evapotranspiration
SS = Soil Storage
D = Discharge
Fate of precipitation and irrigation water
Interception, Infiltration, Runoff, Soil Storage, Enters Groundwater
Interception
Precipitation captured by the plant canopy and its subsequent return to the
atmosphere
3 components of interception
