Soils, Natural Vegetation & Forests: previous-year questions

Answer: (C) Mangrove forest as found in Sunderbans

Per hectare, mangroves store more carbon than any land forest, typically three to five times as much, because besides the trees themselves their waterlogged, oxygen-poor mud locks away large amounts of organic carbon to a depth of several metres. This is called 'blue carbon'. So the Sundarbans mangrove outranks the dry sal forest of Paschim Medinipur, the moist deciduous forest of Buxa and the temperate evergreen forest of Lava. Exam links: blue carbon ecosystems are mangroves, salt marshes and seagrass meadows; the Indian Sundarbans is a National Park, World Heritage Site (1987), Biosphere Reserve and Ramsar site (2019); West Bengal has the largest mangrove cover in India (over 40% of the total), followed by Gujarat; the MISHTI scheme (Budget 2023) promotes mangrove plantation.

Answer: (B) 116 types.

H. G. Champion's 1936 survey classified India's forests into 116 types. The 1968 revision by Champion and Seth regrouped them under 16 type groups with about 200 sub-types, which makes (D) tempting, but that figure belongs to the joint revision. The figures 120 and 110 match neither classification.

Answer: (A) Madhya Pradesh

Answer as of 2023 — this may have changed since.

According to the India State of Forest Reports, Madhya Pradesh has the largest forest cover by area, followed by Arunachal Pradesh and Chhattisgarh. Arunachal has a higher percentage of its area under forest, which makes it tempting, but not the largest area.

Answer: (C) Arunachal Pradesh

Answer as of 2023 — this may have changed since.

Among the listed states Arunachal Pradesh has the largest forest cover, second in India only to Madhya Pradesh, which is not an option. Odisha comes next, while Assam and Himachal Pradesh have far less.

Answer: (B) 3000 – 4000 meters

Alpine and sub-alpine forest of silver fir, juniper, birch and rhododendron occurs in the Himalaya roughly between 3,000 and 4,000 m, above the temperate coniferous belt. The 2,000–3,000 m band belongs to temperate (montane) forest, and above about 4,000 m trees give way to alpine scrub, meadows and snow.

Answer: (A) Flood plain.

Khadar is the new alluvium deposited every year by floods on river flood plains, and is fine and fertile. Older alluvium on higher ground is bhangar, while the foothill and piedmont zones have bhabar and terai deposits, so ‘All of the above’ is wrong.

Answer: (D) West Bengal

Black (regur) soil developed on the Deccan lava plateau covers large parts of Maharashtra, Gujarat, Madhya Pradesh and Andhra Pradesh. West Bengal has mainly alluvial, laterite and red soils, so it is the state where black soil is not found.

Answer: (C) Reserved Forest

Under the Indian Forest Act, 1927, Reserved Forests are the most restricted category: every activity (entry, grazing, collection of produce) is prohibited unless specifically permitted. In Protected Forests it is the other way round — activities are allowed unless specifically prohibited — and local people keep many rights. National Parks and Wildlife Sanctuaries are protected areas under the Wildlife (Protection) Act, 1972, where regulated public entry and tourism are allowed. Reserved forests make up more than half of India's recorded forest area; the third legal category is village or unclassed forest.

Answer: (B) Regur

Regur, the black cotton soil formed from the basalt of the Deccan Traps in Maharashtra, Gujarat and Madhya Pradesh, is best suited to cotton because its clay holds moisture for a long time. It swells when wet and cracks deeply when dry, which is why it is called 'self-ploughing'. Red soil, formed from crystalline rocks, owes its colour to iron oxide. Alluvial soil is the most widespread and fertile soil of India, while peaty soils occur in waterlogged areas such as parts of Kerala.

Answer: (D) Conifer evergreen

At higher altitudes on the southern slopes of the Himalayas, the cool temperate climate supports coniferous evergreen forests of pine, deodar, fir and spruce. Tropical wet (moist) deciduous forests, with teak and sal, grow at lower levels in areas of about 100–200 cm of rain. Dry deciduous forests grow in drier areas of about 70–100 cm of rain. Tropical evergreen forests are found in very wet regions such as the Western Ghats, the North-East and the Andaman Islands.

Answer: (D) Lateritic

Laterite soil forms in areas of high temperature and heavy rainfall, where intense leaching removes lime and silica and leaves iron and aluminium oxides, so it is poor in nitrogen, potash and organic matter. With manure it supports plantation crops such as tea, coffee and cashew. Regur (black soil) is moisture-retentive and good for cotton. Alluvial soils, including bangar (older alluvium with kankar nodules) and khadar (newer alluvium), are among the most fertile soils in India.

Answer: (C) 2 3 4 1

Sub-tropical dry evergreen forests, found in the Siwalik foothills and western Himalayan foothills, are the driest of these types and match the lowest range, 50–100 cm (III–4). Montane wet temperate forests are the wettest and match 150–300 cm (IV–1), and Himalayan moist temperate forests match 150–250 cm (II–3). That leaves 75–125 cm for sub-tropical broad-leaved hill forests (I–2), giving 2, 3, 4, 1. Option (A) is wrong because it gives the 'dry' forests 150–250 cm, more than the moist temperate forests get.

Answer: (D) Haryana

Answer as of 2022 — this may have changed since.

Haryana has the lowest share of its geographical area under forest cover of any state, under 4% in the India State of Forest Report, as most of its land is under intensive agriculture. Punjab is close behind Haryana. Bihar and Tamil Nadu have considerably larger shares. Jammu & Kashmir, now a Union Territory, has extensive Himalayan forests.

Answer: (B) Xerophytes

Plants of dry regions such as the Thar desert are xerophytes, adapted to scarce water with long roots, thick fleshy stems and small or spiny leaves, as in cactus, babul and khejri. Halophytes grow in salty soil or water, such as the mangroves of the Sundarbans. Lithophytes grow on bare rock surfaces. Heliophytes are sun-loving plants that need full sunlight.

Answer: (B) Khadar

Khadar is the newer, lighter-coloured alluvium deposited each year by floods on the low flood plains beside the rivers, and it is very fertile. Bhangar is the older alluvium on higher ground above flood level, containing kankar (lime) nodules. Reh and kallar are saline and alkaline crusts that form on badly drained, over-irrigated land in Uttar Pradesh, Haryana and Punjab. Such usar land is largely barren unless reclaimed with gypsum.

Answer: (C) Alluvial

Alluvial soil is the most widespread soil in India, covering roughly 40% of the land, mainly in the Indo-Gangetic–Brahmaputra plains and the coastal deltas. Red soils, formed on crystalline rocks of the peninsula, and black soils each cover roughly a sixth of the country. Black (regur) soil covers much of the Deccan lava plateau and is ideal for cotton. Laterite soil occurs in high-rainfall areas such as the Western Ghats, the Eastern Ghats and parts of the North-East.

Answer: (C) Karnataka

Karnataka has the largest area of natural sandalwood forest in India, and Mysore sandalwood and its oil and soap are world famous. Kerala also has sandalwood, notably at Marayur in Idukki district, which makes (D) the tempting option. Madhya Pradesh is known for teak and sal forests and has the largest forest area of any state. Maharashtra has no major natural sandalwood belt.

Answer: (B) Alluvial, Black, Red, Laterite

Alluvial soil, covering about 40% of India, has the largest share, so options (A) and (C) are wrong. Black soil of the Deccan lava plateau and red soil of the crystalline peninsula each cover roughly a sixth of the country, and the keyed order places black second and red third. Laterite soil covers only about 4%, the smallest of the four. Option (D) is wrong because it ranks laterite above red soil.

Answer: (B) Kari

The black, heavy, highly acidic peaty soils rich in organic matter found in the Kuttanad area (Alappuzha and Kottayam districts) of Kerala are locally called 'Kari'. Reh, Kallar, Thur (and also Usar, Rakar, Chopan) are all local names of saline and alkaline soils of the dry parts of Uttar Pradesh, Punjab, Haryana and Rajasthan. Peaty and marshy soils also occur in the Sundarbans, coastal Odisha and northern Bihar.

Answer: (D) Andhra Pradesh

The question means the Coringa mangroves ('Loringa' is a misprint in the booklet). The Coringa Wildlife Sanctuary lies in the Godavari delta near Kakinada in Andhra Pradesh and is one of the largest mangrove tracts in India after the Sundarbans. Mangroves of the other options: Bhitarkanika in Odisha (Brahmani-Baitarani delta), the Gulf of Kachchh in Gujarat, and the Vembanad-Kannur backwaters in Kerala. Pichavaram is in Tamil Nadu.