IV. Answer the following questions in brief.
1. What is the difference between topsoil and subsoil?
2. How will you differentiate between soil erosion and soil exhaustion?
3. Differentiate between mulching and fallowing?
4. Why is water considered a valuable resource?
5. Why is ocean water of limited use to humans? What makes it a resource?
Answers
Answer:
(1) ans=The topsoil is the uppermost layer and has these features: It's usually darker in color than the subsoil since it contains more organic matter from decaying plants and their roots. ... The subsoil is located between the topsoil and the parent rock (or material) below.
(2) ans=In agriculture, soil erosion refers to the wearing away of a field's topsoil by the natural physical forces of water and wind or through forces associated with farming activities such as tillage. Soil Exhaustion - Soil exhaustion occurs when poorly managed soils are no longer able to support crops or other plant life.
(3) ans=Human kidneys can only make urine that is less salty than salt water. Therefore, to get rid of all the excess salt taken in by drinking seawater, you have to urinate more water than you drank. Eventually, you die of dehydration even as you become thirstier.
(4) ans=Water resources are sources of water that are useful or potentially useful to humans. It is important because it is needed for life to exist. Many uses of water include agricultural, industrial, household, recreational and environmental activities. Virtually all of these human uses require fresh water.
(5)ans=Ocean water is not fit for human use due to the high salt content. It contains about 10,000-35,000 ppm of dissolved salts. Such a large amount of salt can cause dehydration if used for drinking purposes. ... Ocean water is an important resource as it is responsible for climate changes.
Explanation:
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