The correct answer is option 4: Arid soil. Arid soils are found in dry regions with limited rainfall. These soils have high salt content due to the process of salinization caused by the evaporation of water, leaving behind salts. In some areas with arid soil, saline water is present underground. When this saline water is evaporated, common salt is obtained.

Option 1: Peaty soil is not the correct answer. Peaty soil is characterized by the accumulation of partially decomposed organic matter and is found in waterlogged areas such as swamps and marshes. It does not have high salt content.

Option 2: Alluvial soil is not the correct answer. Alluvial soil is formed by the deposition of sediments brought by rivers and is found in river valleys. It does not have high salt content.

Option 3: Laterite soil is not the correct answer. Laterite soil is typically found in tropical regions and is formed through intense weathering. It does not have high salt content.

Therefore, the correct answer is Arid soil (option 4).