D. Answer the following questions in brief.
1.
Why is soil considered an important resource? Give any three reasons.
2.
Highlight any three causes of soil erosion.
3.
Explain hydrological cycle with the help of a diagram.
How does river water get polluted? Explain.
4.
5.
Identify any three ecological problems caused by building large dams.
Answers
Answer:
1⃣Soil is veryimportant for the growth of plants. 2⃣Indirectly, animals also depend upon the soil to satisfy their basic needs, as soil gives nutrients to plants. 3⃣It gives shelter to insects and animals like rats, snakes, ants, earthworms etc
2.Soil compaction, low organic matter, loss of soil structure, poor internal drainage, salinisation and soil acidity problems are other serious soil degradation conditions that can accelerate the soil erosion process. This Factsheet looks at the causes and effects of water, wind and tillage erosion on agricultural land.
3.The water cycle includes the process of evaporation, condensation and precipitation. The heat of the Sun evaporates water resulting in the formation of water vapour. When the water vapour cools down, it condenses and form clouds.
5.Construction of dams have resulted in problems like excessive sedimentation and salinity, waterlogging, sudden floods, soil erosion, large scale deforestation, extinction of species, health hazards, displacement of local communities and loss of livelihood of tribal communities