Correct option is B
A lysimeter is a device used to measure evapo-transpiration it is a held method
A lysimeter is an instrument used to measure the evapo-transpiration from a particular area of soil, typically a small, contained plot. Evapo-transpiration is the sum of water evaporation from the soil surface and transpiration by plants. Lysimeters are used in agricultural and environmental studies to accurately assess the water balance and the amount of water required by crops.
Lysimeters Work:
A lysimeter typically consists of a container filled with soil and vegetation similar to the surrounding field. It is placed in the ground so that the surface of the soil in the lysimeter is level with the surrounding soil.
The amount of water added to the lysimeter (through precipitation or irrigation) and the amount of water that drains from it are measured.
By knowing the inputs (rainfall, irrigation) and outputs (drainage, changes in soil moisture), the amount of water lost through evapo-transpiration can be calculated.
