The Soil

11. Capillaries are most effective in [53rd to 55th B.P.S.C. (Pre) 2011]

(a) Clayey soil
(b) Silt soil
(c) Sandy soil
(d) Loamy soil

Correct Answer: (a) Clayey soil

Solution:Smaller the pore of the soil, more effective is the capillary activity and bigger the pore of any soil, less effective will be its capillary activity. In clay soil, the capillary activity is most effective and it is least in sandy soil. The effectiveness of the capillary activity in these four soils are as follows:

Clay > silt soil > loamy soil > sandy soil

12. Conservation of soil is the process in which- [39th B.P.S.C. (Pre) 1994]

(a) Barren land is converted into fertile
(b) Soil is aerated
(c) Soil is eroded
(d) Soil is conserved from harm

Correct Answer: (d) Soil is conserved from harm

Solution:

In a broad sense, the meaning of soil conservation is not only controlling erosion, rather it aims at maintaining high-level fertility of the land. The improvement in land use is called soil conservation. Hence, correct answer is (d).

13. The formal development of Terrarossa takes place in that part of land which consists of [39th B.P.S.C. (Pre) 1994]

(a) Limestone
(b) Cynite
(c) Granite
(d) Sandstone

Correct Answer: (a) Limestone

Solution:Terrarossa is a type of red clay soil produced by the weathering of limestone and Dolomites rocks. Terrarossa is thought to form primarily from the insoluble residue of limestone and dolomite rocks, with some evidence suggesting that it can also be influenced by other materials like aeolian dust and terrigenous clastic inputs.

The reddish color of terra rossa is a result of the preferential formation of hematite (a type of iron oxide) over goethite, a process known as "rubification". Terrarossa is particularly common in areas with Mediterranean-type climates and karst terrains, especially around the Adriatic Sea, where it is found covering limestone and dolomite bedrock. Terrarossa is typically characterized by high internal drainage and neutral pH conditions.

14. Soil leaching is a major problem - [U.P.P.C.S. (Pre) 1998]

(a) In tropical rainforests
(b) In African savanna
(c) In mediterranean regions
(d) In Australian Dawns

Correct Answer: (a) In tropical rainforests

Solution:Tropical rain forest regions of the world are facing the soil leaching problem due to heavy rainfall throughout the year. Hence, the correct answer is option (a).

Tropical rainforest soils are often nutrient-poor due to the high rainfall, which leads to rapid leaching (washing away) of nutrients. In rainforests, most nutrients are rapidly recycled within the living vegetation and rapidly decomposed organic matter, leaving little in the soil. When rainforests are cleared, the soil is exposed to intense rainfall and sunlight, leading to erosion and further nutrient loss.

The combination of nutrient-poor soil and the difficulty of establishing new trees in such conditions makes regeneration of a tropical rainforest much slower than that of a tropical deciduous forest. Tropical deciduous forests, which experience a distinct dry season, tend to have more fertile soils, and the trees are adapted to survive and regenerate more readily in such conditions.

15. Halophytes grow well in- [M.P.P.C.S. (Pre) 2014]

(a) Acidic soils
(b) Cold soils
(c) soil containing calcium
(d) Saline soils

Correct Answer: (d) Saline soils

Solution:

Halophytes grow well in saline soil. Cryophytes grow well in cold soil. Plants growing in strong rocks are called Lithophyte and xerophytes grow in tropical desert areas. Hygrophytes grow well in water-logged areas and Hydrophytes are aquatic plants.

16. Which of the following adds/add nitrogen to the soil? [I.A.S. (Pre) 2013]

1. Excretion of urea by animals

2. Burning of coal by man

3. Death of vegetation

Select the correct answer using the codes given below:

(a) 1 only
(b) 2 and 3 only
(c) 1 and 3 only
(d) 1, 2 and 3

Correct Answer: (c) 1 and 3 only

Solution:Excretion of urea by animals and dead vegetation are decomposed by decomposers. This process helps plants getting nutrients from them. In this way, the continuous process of nitrogen cycle goes on and the soil gets the required amount of nitrogen.