Correct Answer:
(C)
Afforestation
Soil conservation includes all the methods to check soil erosion and maintain soil fertility. Some of the effective ways to prevent soil erosion are – afforestation, contour tillage, banning shifting cultivation, etc.
Ques:
22
Which of the following practices can help in water conservation in agriculture?
Reduced on zero tillage of the land
Applying gypsum before irrigating the field
Allowing crop residue to remain in the field
Select the correct answer using the code given below:
Correct Answer:
(C)
1 and 3 only
Reduced or zero tillage of the land in farming is a way of growing crops or pasture year to year without disturbing the soil through tillage, so, it helps in soil moisture conservation. Gypsum helps in dissolution of the salt clay pan found in soils that obstructs the percolation of water. So, it increases the efficiency of irrigation. Allowing crop residue to remain in the field reduces evaporation of water from the soil. So, all the statements are correct.
Using surface residue covers to increase infiltration and reduce runoff. A residue cover absorbs most of the energy of the raindrops that fall on it and by the time this rainwater reaches the soil below, its ability to disintegrate soil aggregates and detach fine particles is greatly reduced.
Using Impermeable and permeable contour barriers at discrete intervals downslope combined with reduced tillage, or preferably zero tillage as in conservation agriculture.
The incorporation of lime without or with gypsum will reduce toxic concentrations of aluminium and/or manganese to non-toxic levels and so encourage deeper rooting enabling the crop to access more soil moisture. Gypsum increase the porosity of soil, in result which increase water infiltration in soil. Hence statement 1 and 3 are correct.
Ques:
23
Which of the following statements regarding laterite soils of India are correct?
They are generally red in colour
They are rich in nitrogen and potash.
They are well-developed in Rajasthan and Uttar Pradesh.
Tapioca and cashew nuts grow well on these soils.
Select the correct answer using the codes given below
Correct Answer:
(C)
1 and 4
The laterite soil is red in colour due to the wide diffusion of iron oxides through the materials of the soil. Generally, Laterite soil is deficient in nitrogen, lime, humus, but rich in Iron & Aluminium. Laterite soil is mostly found in South Maharashtra, parts of Karnataka, Kerala, and Meghalaya. Typical Laterite soils generally lack fertility and are of little use for crop production. Tapioca and Cashew nuts grow well on these soils.
Ques:
24
Given below are two statements, one is labelled as Assertion (A) and the other as Reason (R).
Assertion (A): The percentage of net sown area in the total area of Andhra Pradesh is less as compared to that of West Bengal.
Reason (R): The soil of most of Andhra Pradesh is laterite.
Code:
(A) and (R) are individually true, and (R) is the correct explanation of
(A).
Correct Answer:
(C)
'A' is true, but 'R' is false.
The net sown area of West Bengal is approximately 60% while it is 40% in Andhra Pradesh. Thus, statement (a) is correct. The Laterite soil is formed in heavy rainfall areas by leaching. They are well developed in parts of Western Ghats, Eastern Ghats, South Maharashtra, parts of Karnataka, Andhra Pradesh, Orissa, West Bengal, Kerala, Jharkhand, Assam, and Meghalaya. Andhra Pradesh has red soil and Alluvial soils in most parts of its area. Thus, reason (R) is not correct.
Ques:
25
Laterite soils is found in:
Correct Answer:
(D)
Maharashtra
Laterite soil is found in typical monsoon conditions such as high temperature and heavy rainfall with wet and dry periods. The alterations of the wet and dry season lead to the leaching away of siliceous matter and lime of the rocks and a soil rich in oxides of iron and aluminium compounds is left behind. These are leached soils of wet humid tropical regions which are less fertile. They are well developed in parts of Western Ghats, Eastern Ghats, South Maharashtra, parts of Karnataka, Andhra Pradesh, Odisha, West Bengal, Kerala, Jharkhand, Assam and Meghalaya. Laterite soils are widely spread in India and cover an area of 1.80 lakh sq. km. Laterite soil is mostly spread in Kerala (Malabar coastal region) followed by Maharashtra. Kerala is not present in the option, so most probable answer would be Maharashtra.
Ques:
26
Which one of the following soil types of India is rendered infertile by the presence of excess iron?
Correct Answer:
(D)
Lateritic
Among the above soils, only Laterite soils have iron oxides. Hence, Laterite soil of India is rendered infertile by the presence of excess iron.
Ques:
27
Which one of the following soils is deposited by rivers?
Correct Answer:
(C)
Alluvial soil
Alluvial soil is formed by the silt released from the rivers. Alluvial soils are divided into two subclasses -
New Alluvium or Khadar - It is deposited by floods annually, which enriches the soil by depositing fine silts.
Older Alluvium or Bhangar - It represents a system of older alluvium, deposited away from the flood plains.
Ques:
28
Which one of the following is the most productive soil
in India?
Correct Answer:
(C)
Alluvial soil
Alluvial soil is the most fertile soil in India. It has less amount of Nitrogen. Alluvial soils are formed mainly by Himalayan sediments and sea retreat. It covers 11 lakh sq. km of land.
Ques:
29
In India, the largest soil group is found as:
Correct Answer:
(D)
Alluvial Soil
Alluvial soil is the largest and the most important soil group of India. Covering about 11 lakh sq. km or about 33.5% of the total land area of the country, these soils contribute the largest share of our agricultural wealth. The widest occurrence of the Alluvial soils is in the Indo-Gangetic plain starting from Punjab in the West, to West Bengal and Assam in the East. They are also found in deltas of Mahanadi, Godavari, Krishna and Cauvery, where they are called deltaic alluvium. Along the coast, they are known as coastal alluvium. Some alluvial soils are found in Narmada and Tapi valleys. Geologically, the alluvium is divided into newer or younger Khadar and older Bhangar soils. Geographically, Black soils are spread over 5.46 lakh sq. km while the red soils occupy a vast area of about 8.7 lakh sq. km.
Ques:
30
Old Kachhari clay of Gangetic plain is called
Correct Answer:
(B)
Bhangar
Geologically, the alluvium of the great plain of India is divided into newer or younger khadar and older bhangar soils. Bhangar is found on the higher level beyond the reach of floods. Bhangar soil contains calcareous concretions and is generally pale reddish brown in colour.