Q. Consider the following:

1. Pyrite
2. Gypsum
3. Organic Manure

Which among the above can be used in reclamation of the Alkali soil?
Answer: All 1, 2 and 3
Notes: All, namely Pyrite, Gypsum and Organic Manure, can be used for reclamation of Alkali soil. Pyrite reacts with water to form sulphuric acid which can neutralise alkaline soil. Gypsum provides calcium which displaces sodium ions from the soil particles leading to improvement in soil structure. Organic manure improves the soil structure and its capacity to hold water.