Soil pH Flashcards
Define pH
pH= -log ｜H+｜???
What is Active Acidity
In soil solution
What is Reserve Acidity
On Cation exchange sites
How can you find Total Acidity
Total Acidity= active + reserve
Where are micronutrients and macronutrients availability maximized on the pH scale
6.5
Buffering Capacity
The solubility against rapid pH changes
What is Buffering Capacity determined by
Amount of CEC and the amount of Reserved acidity
What does Buffering capacity determine
The amount of Lime and Sulfur to change soil pH
What is the importance of soil pH
Nutrient availability
Makes balance of cations on CE sites
Influenced chemical forms
Alters microbial activity
What Two factors affect soil pH
- Carbonate content of soils
- Leaching status of soils
How is Hydroxide produced
It is produced when free calcium carbonate is available
Describe the conditions that result in ACIDIC REGIONS
Humid region
High rainfall
Bases leached
Describe the conditions that result in NEUTRAL to ALKALINE CONDITIONS
Arid regions
Low rainfall
Bases remain
What are 5 sources of Acidity
- Acid parent material
- Respiration by Roots and Microbes
- Decomposition of OM-produces strong acids
- Leaching & plant uptake of basic cations
- Addition of amendment that will alter pH
What pH value does Aluminum become soluble
pH<5.0
As Aluminum becomes ______ it brings more _____
More soluble
Hydrogen ions
NOT GOOD
As base saturation ______ pH ______
Increases
Decreases
In what two ways can we alter soil pH
And what are their affects
Adding Lime- Increase
Adding Sulfur- Decrease
How can we determine the Lime requirement
Soil test- Reserve acidity
What is the Lime Requirement depend on
CEC
Soils with longer CEC have higher Buffering Capacity & offer greater resistance to change in pH
What are the Two forms of Lime
Calcite
Dolomite
What can be applied for quicker reactions?
Calcium Hydroxide
What is the preferred particle size & method to change pH with Lime
Medium particles
50% passing through 100 mesh screen
Must apply evenly and mix
