CBSE Class 8 Social Science Chapter 2: Land, Soil, Water, Natural Vegetation and Wildlife Resources NCERT Solutions

Solution:

(i) The two primary climatic factors that significantly influence soil formation are temperature and rainfall. Fluctuations in temperature can cause rocks to expand and contract, leading to cracks. Rainfall contributes to the weathering of rocks by physical and chemical processes, and also helps in transporting weathered material.

(ii) Two significant reasons for land degradation today are:

• The ever-growing demand of the increasing global population, which leads to overuse of land resources.
• The destruction of forest cover through deforestation, which exposes the soil to erosion and degradation.

(iii) Land is considered an extremely important resource because it serves as the foundation for most human activities. It provides the surface for agriculture, housing, industries, forestry, and infrastructure development. Without land, many essential activities and settlements would not be possible.

(iv) The government has implemented several measures to conserve plants and animals. Two key steps include:

• The establishment of National Parks, which are protected areas dedicated to conserving the natural environment and wildlife within them.
• The creation of Wildlife Sanctuaries, which provide a safe habitat for animals and protect them from hunting and habitat destruction.

(v) Three effective ways to conserve water are:

• Rainwater Harvesting: This involves collecting and storing rainwater for later use, reducing reliance on other water sources and replenishing groundwater.
• Improving Irrigation Systems: Ensuring that canals used for irrigation are properly constructed and maintained helps minimize water loss during transportation to fields.
• Efficient Irrigation Techniques: In dry or arid regions, adopting methods like drip or trickle irrigation significantly reduces water wastage by delivering water directly to the plant roots.

Solution:

(i) The correct answer is (b) soil texture. Soil texture refers to the size of soil particles (sand, silt, clay) and is a characteristic of the soil itself, not a factor that causes its formation. Time, organic matter, and climatic factors are crucial for soil formation.

(ii) The most appropriate method to check soil erosion on steep slopes is (c) terrace cultivation. This method involves creating flat steps or terraces on the slope, which slows down water runoff and prevents soil from being washed away.

(iii) The action that is NOT in favour of the conservation of nature is (c) dispose polypacks after shopping. Polypacks (plastic bags) contribute to pollution and waste. Switching off lights when not in use and closing taps immediately are direct conservation actions for energy and water, respectively.

Solution:

The correct matching is:

• (i) Land use is matched with (c) productive use of land, as it refers to how land is utilized for various purposes like farming, housing, or industry.
• (ii) Humus is matched with (d) organic matter deposited on top soil. Humus is the rich, dark organic material formed from decomposed plant and animal matter, which enriches the topsoil.
• (iii) Rock dams are matched with (a) prevent soil erosion. Building dams with rocks, especially across gullies or streams, helps to slow down water flow and reduce soil erosion.
• (iv) Arable land is matched with (b) land suitable for agriculture. Arable land is land that can be used for growing crops.

Solution:

(i) True. The Ganga-Brahmaputra plain is a fertile river valley with flat land, which supports intensive agriculture and has historically attracted large populations, making it one of the most densely populated regions in the world.

(ii) True. Due to the increasing population and rising demand for water for agriculture, industry, and domestic use, the per capita availability of water in India is decreasing.

(iii) False. Rows of trees planted in coastal or arid areas to check wind movement are called shelter belts, not intercropping. Intercropping involves growing two or more crops simultaneously in the same field.

(iv) False. While ecosystems are dynamic, significant human interference and drastic changes in climate often disrupt the natural balance and can lead to the degradation or collapse of ecosystems, rather than their maintenance. Minor, sustainable human activities might be integrated, but major changes are typically detrimental.

Solution:

(i) The correct option is (d) water. Water covers approximately 71% of the Earth's surface, which is about three-fourths.

(ii) Low-lying areas are very susceptible to (c) flooding. When rivers overflow or heavy rainfall occurs, these areas are the first to be inundated.

(iii) (a) plains and river valleys are the physical features best suited for living. They offer fertile soil for agriculture, relatively flat terrain for construction and transportation, and access to water resources.

(iv) An example of community land is (d) none of these. Community land, also known as common property resources, is typically used by all members of a community, such as grazing grounds or village forests. The Sunderban forests are a protected area, a bungalow is private property, and the Parliament House is a government building.

(v) The majority of land in India is used for (a) cultivation. Agriculture is a primary occupation and land use in India, with a large percentage of the total land area dedicated to farming.

(vi) Both (b) Brazil and (c) USA have significant forest cover, with Brazil having vast areas of the Amazon rainforest. Therefore, (d) both b and c is the most appropriate answer, although Brazil's forest cover percentage is notably higher relative to its landmass than the USA's.

(vii) Ocean water is unfit for human consumption primarily due to its high (b) salinity. The concentration of dissolved salts in seawater is too high for humans to drink without adverse health effects.