An alkali soil must have pH value of

A. Less than 7.0

B. 7.0 - 7.5

C. 7.5

D. Above 8.5

Answer: Option D

Solution(By Examveda Team)

An alkali soil must have a pH value of above 8.5.
Alkali soils are clay soils with high pH, a poor soil structure, and a low infiltration capacity. They also have a hard calcareous layer at 0.5 to 1 metre depth.
Alkali soils owe their unfavorable physio-chemical properties mainly to the dominating presence of sodium carbonate, which causes the soil to swell and is difficult to settle.