The correct option is "3 only" because irrigation practices, especially in arid and semi-arid regions, can lead to the accumulation of soluble salts in soil, resulting in salinization. This occurs when water evaporates, leaving salts behind, which can adversely affect crop growth and soil health. In contrast, statement 1 is incorrect as high organic matter typically increases water holding capacity, and statement 2 is also incorrect because soil plays a significant role in the sulfur cycle through mineralization and the storage of sulfur compounds.