Question

Alkali soils are reclaimed by ___________

(a) leaching of soil

(b) using limestone as a soil amendment

(c) using gypsum as a soil amendment

(d) provision of drainage

This question was posed to me by my school teacher while I was bunking the class.

My query is from Reclamation of Saline and Alkaline Lands topic in section Water Logged Reclamation and Saline Soils for Agricultural Purposes of Irrigation Engineering

Answer 1

Correct answer is (c) using gypsum as a soil amendment

Easy explanation: Alkali soils are best reclaimed by cationic exchange i.e. replacement of alkali from soil colloids by calcium ions. Application of gypsum in the soil reduces alkalinity to a great extent and makes the soil fertile. Good drainage leaches away the by-product of the reaction.