Question

The water held tightly by the soil particles around them is known as
A. Field capacity
B. Runaway water
C. Hygroscopic water
D. Capillary water

Answer 1

Field capacity implies total water content in a field including hygroscopic water, capillary water, and chemically bound water whereas runaway water is also not free to plants and hygroscopic water is the water that is held tightly by soil particles around them in a very thin film and is not available to plants. Plants are able to consume capillary water which is existing in the capillary spaces between soil particles.

Complete step-by-step answer:
Option A- Field capacity
The amount of soil moisture or water content held in the soil after excess water has drained away is known as Field Capacity. The rate of downward movement decreases. This usually takes place 2–3 days after rain or irrigation in former soils of consistent structure and texture.

Option B- Runaway water
Surface runoff is also known as overland flow. It is the flow of water happening on the ground surface when excess rainwater, stormwater, meltwater, or other sources, can no longer sufficiently infiltrate in the soil. Surface runoff is an important component of the water cycle.

Option C- Hygroscopic water
It is the water absorbed from the atmosphere and held very tightly by the soil particles. It is unavailable to plants in having enough amounts of water available to them to survive.

Option D- Capillary water
It is the water that remains in the soil after gravitational water is drained out. It is subject to the laws of capillary movement. It is seen in the form of a film around the soil grains.

Therefore, the correct answer is Option C- Hygroscopic water.

Note: Water moves by gravity into the open pore spaces in the soil. The size of the soil particles and their spacing assumes how much water can flow in. In other words, a soil with an increased percentage of silt and clay particles, (describing fine soil) has a higher water-holding capacity.