Soil chemical properties and processes

Question 1

What is isomorphous substitution

Answer 1

Clay minerals develop a permanent negative charge due to isomorphous substitution where ions of a similar size replace each other
this doesnt disrupt structure but effect cation exchange capacity in the soil

Question 2

Cation exchange

Answer 2

soils adsorb ions on negatively charged surfaces
these ions are available for plant uptake but can be displaced by other ions in the soil solution

Question 3

Sorption

Answer 3

nutrients and contaminants can adsorb to soil particles or precipitate in insoluble compounds which affects mobility and bioavailability

Question 4

Sodicity

Answer 4

high Na on exchange sites whcih disperses clay particles and damages the structure
defined as Exchangeable Sodium Percentage greater than 6%

Question 5

Salinity

Answer 5

excess soluble salts which inhubits plant growth
measured as Electrical conductivity of hugher than 4dS/m

Question 6

Gypsum

Answer 6

applied to displace sodium with calcium ions which promotes flocculation in the soil

Question 7

what is flocculation

Answer 7

clumping of soil particles leading to improved soil structure