PLANT PHYSIOLOGY
PLANT GROWTH
|
Question
[CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
|
|
|
O horizon
|
|
|
A horizon
|
|
|
B horizon
|
|
|
C horizon
|
Detailed explanation-1: -Most commonly called topsoil, the A horizon is a layer of mineral soil that has a defined soil structure, and it is mostly made up of humus (decayed organic matter). The A horizon may be a result of soil disturbance by plant and animal activity.
Detailed explanation-2: -The horizons are: O (humus or organic): Mostly organic matter such as decomposing leaves.
Detailed explanation-3: -The O horizon is the upper layer of the topsoil which is mainly composed of organic materials such as dried leaves, grasses, dead leaves, small rocks, twigs, surface organisms, fallen trees, and other decomposed organic matter.
Detailed explanation-4: -A-Horizon, the topmost layer of the soil profile is soft, porous, rich in humus and minerals. It is in this layer that most of the plants grow. Many living organisms like earthworms, rodents, etc live in this layer.