Agronomy Degree Practice Exam

What term describes soil particles that are 0.002 to 0.02 mm in diameter?

1. Silt

2. Clay

3. Loam

4. Sand

The correct answer is: Silt

The term that describes soil particles with a diameter ranging from 0.002 to 0.02 mm is silt. Silt particles are finer than sand, which has a larger particle size (typically 0.05 to 2 mm) but coarser than clay, which is defined as particles smaller than 0.002 mm. Understanding soil texture is essential in agronomy because the size of soil particles affects water retention, drainage, and nutrient availability. Silts are particularly important in agriculture as they hold moisture better than sand while still allowing for good drainage, making them a valuable component in fertile soils. Loam, on the other hand, is a mixture of sand, silt, and clay, but does not specifically refer to a size range. Thus, the classification of soil based on size is crucial for determining soil properties and suitability for various agricultural practices.