Q. With reference to agricultural soils, consider the following statements:

1. A high content of organic matter in soil drastically reduces its water holding capacity.
2. Soil does not play any role in the sulphur cycle.
3. Irrigation over a period of time can contribute to the salinization of some agricultural lands.

Which of the statements given above is/are correct?

• 1 and 2 only
• 3 only
• 1 and 3 only
• 1, 2 and 3

Answer: (b) 3 only

Notes:

• Soil water-holding capacity is the amount of water that a soil can hold for crop use.
  • Soil texture and organic matter are the key components that determine soil water holding capacity.
• Sulpur is one of three nutrients that are cycled between the soil, plant matter and the atmosphere.
  • Although sulphur is primarily found in sedimentary rocks, it is particularly important to living things as it is a component of many proteins.
  • Sulphur is released by the weathering of rocks and minerals.
• Soil salinity is an enormous problem for agriculture under irrigation.
  • Irrigation over a period of time can contribute to the salinization of some agricultural lands as deposits of salts build up in the soil and can cause harm to crops.