Bihar Climate, Soils and Forests: Rainfall and Zones

The correct answer is C, humid subtropical monsoon. Bihar lies in the northern plain, where summers are hot, the rain comes in a single spell from the south-west monsoon between mid-June and early October, and winters are cool and dry with occasional cold waves. That combination of a hot summer, a wet monsoon and a dry winter is what the humid subtropical monsoon type means.

Option A, equatorial, describes a climate that is hot and wet throughout the year with no dry season, as in the Amazon or the Congo basin, and nothing in India fits it except the Andaman and Nicobar group in part. Option B, hot desert, is the climate of western Rajasthan, with very low and uncertain rain. Option D, Mediterranean, has winter rain and dry summers and is found in coastal California, southern Europe and parts of Chile, the opposite of the Bihar pattern. Remember that the whole state lies north of the Tropic of Cancer, which is why it is subtropical rather than tropical in type.

The correct answer is A, from north-east to south-west. The rain comes to Bihar with the Bay of Bengal branch of the south-west monsoon, which enters from the east and loses moisture as it moves inland. So Kishanganj, Araria and Purnia in the north-east are the wettest districts, the Champaran belt is well watered, and Gaya, Aurangabad and the Kaimur tract in the south-west receive the least and suffer drought most often.

Option B reverses the real pattern of the north, where the Himalayan foothills get more rain, not less. Option C, from west to east, is the pattern of the Ganga plain as a whole only if you read it the other way round: rainfall rises eastwards from Punjab towards Bengal. Option D is wrong because the difference across Bihar is large, from well over 1,500 millimetres in the north-east to around a thousand in the south-west. This gradient is the reason flood is a North Bihar problem and drought a South Bihar one.

The correct answer is A, Kishanganj. Kishanganj lies in the extreme north-east of the state, in the corner nearest the Darjeeling hills and the moist Bengal duars, and it is the first part of Bihar the monsoon current reaches. It is the wettest district of the state, and the neighbouring districts of Araria and Purnia come close behind it.

Option B, Gaya, in the south-west, is one of the driest and hottest districts and is a standard example of the drought-prone South Bihar plain. Option C, Aurangabad, lies next to Gaya in the same dry tract and depends on the Sone canal system for irrigation. Option D, Rohtas, is also in the south-west, in the Kaimur country, and is irrigated rather than well watered. The examiner's point is always the same contrast: wettest in the north-east, driest in the south-west.

The correct answer is B, the Bay of Bengal branch. This branch of the south-west monsoon strikes the Bengal coast, is deflected west by the Himalaya and moves up the Ganga plain, reaching Bihar in the second week of June. Because the current travels from east to west across the state, the north-east gets the rain first and most heavily, and the south-west gets the least.

Option A, the Arabian Sea branch, waters the west coast, the Western Ghats and central and north-west India, and only a weakened remnant of it reaches the eastern plain. Option C, the retreating monsoon of October and November, gives rain to the Tamil Nadu coast, not to Bihar, where those months are dry and clear. Option D, western disturbances, are winter depressions from the Mediterranean that bring a little rain to north-west India and sometimes light showers to Bihar in January, useful for the rabi crop but a very small part of the annual total.

The correct answer is B, three. For agricultural planning Bihar is divided into Zone I, the north-west alluvial plain, Zone II, the north-east alluvial plain, and Zone III, the South Bihar alluvial plain, which is further subdivided into III A and III B. The division follows the two things that actually differ across the state: the Ganga, which separates north from south, and the rainfall gradient, which separates the wet north-east from the drier north-west and south.

Option A, two, would be right only if the Ganga were the sole basis of the division. Option C, five, and option D, seven, are the kinds of numbers used for other states and for the national scheme of agro-climatic regions, in which Bihar falls in the middle Gangetic plain region. For the exam, hold on to three main zones with the southern one split in two, and remember that Zone II, the north-east, is the wettest and the most flood-affected.

The correct answer is A, calcareous, that is rich in lime. The rivers of North Bihar come down from the young Himalaya and spread fresh silt over the plain at every flood, and that silt carries a high proportion of lime. The soil is therefore light in texture, pale, low in nitrogen and organic matter, and renewed each year, which is why it responds so well to manure and to balanced fertiliser.

Option B, lateritic soil, forms under heavy rain on old rock with leaching, and in Bihar it occurs only in patches on the Kaimur fringe and in Jamui, Banka and Munger. Option C, black and highly clayey, describes the karail soil of the Son valley and the tal soil of the Mokama belt, both of them South Bihar types. Option D is wrong as a general statement: saline and alkaline usar patches do occur in canal commands, but they are local, not a character of the whole belt. The clean pairing to remember is newer alluvium with calcareous North Bihar and older alluvium with clayey South Bihar.

The correct answer is A, the Mokama belt of Patna, Nalanda and Lakhisarai. South of the Ganga, between the river and the higher ground inland, lies a stretch of low saucer-like land called tal, of which the Mokama tal is the largest. Water collects there through the monsoon and drains late, leaving a very heavy, dark, moisture-holding clay on which rabi pulses, especially gram, lentil and khesari, give excellent yields.

Option B, the Shivalik foothills of West Champaran, carries piedmont swamp soil, gravelly and badly drained, a different type altogether. Option C, the Kaimur plateau of Rohtas, has thin red, yellow and lateritic soils formed on old rock. Option D, the Kishanganj and Araria plain in the north-east, has light, acidic, sandy alluvium under the heaviest rain in the state. The four local soil names worth separating for the exam are tal, karail, diara and terai, and the tal is the one tied to pulses.

The correct answer is B, black, moisture-retentive clay. Karail is the dark, sticky clay of the Son valley and the adjoining parts of Rohtas and Bhojpur districts. It holds moisture for a long time, cracks when it dries, and under the Sone canal system it carries good paddy in the kharif season and wheat and gram afterwards, which is why this tract is counted among the more productive parts of South Bihar.

Option A, coarse sandy soil of the river bed, is diara soil, the land between the channels of the Ganga, where melons, cucumbers and vegetables are grown after the flood recedes. Option C, lime-rich light alluvium, is the newer alluvium or khadar of the North Bihar plain, renewed by the Himalayan rivers. Option D, red lateritic soil, is found in patches on the Kaimur fringe and in Jamui, Banka and Munger, where old rock lies near the surface. Pair karail with the Son valley and with the word black whenever it appears in an option.

The correct answer is B, Valmiki. The Valmiki Tiger Reserve lies in West Champaran district, along the Nepal border at the foot of the Shivaliks, and it is the only tiger reserve in Bihar. Its forest is tropical moist deciduous, with sal as the main tree, and it adjoins the Chitwan landscape across the border in Nepal, which is what makes it important for tiger movement.

Option A, Kaimur, in Kaimur and Rohtas districts, is a wildlife sanctuary and the largest protected area in the state, but it is not a tiger reserve. Option C, Bhimbandh, in Munger district, is a sanctuary known for its hot springs in dry deciduous forest. Option D, Gautam Buddha, is a sanctuary in the Gaya and Jamui country. Two facts travel together here and are often asked in one question: Valmiki is the only tiger reserve and Kaimur the largest sanctuary of Bihar.

The correct answer is A, the Kaimur Wildlife Sanctuary. It is spread across Kaimur and Rohtas districts on the Kaimur plateau in the south-west of the state, and by area it is the largest protected area in Bihar. The forest there is tropical dry deciduous, with khair, palas, mahua and bamboo, and the plateau also holds waterfalls, caves and the Durgavati reservoir.

Option B, Bhimbandh in Munger district, is a well-known sanctuary with hot springs but much smaller. Option C, Rajgir, in Nalanda district, is a small sanctuary in the hills around the old Magadhan capital. Option D, Udaipur, in West Champaran, is a small sanctuary close to the Valmiki forest. Remember the superlatives as a set: Valmiki the only tiger reserve, Kaimur the largest sanctuary, and Vikramshila in Bhagalpur the only Gangetic dolphin sanctuary.

The correct answer is A, the gaur or Indian bison. The gaur is the state animal of Bihar, the house sparrow is the state bird, the peepal is the state tree and the kachnar is the state flower. These four symbols are asked almost every year in state recruitment papers, usually as a match-the-following set, so they are worth learning together rather than one at a time.

Option B, the tiger, is the national animal of India and the flagship species of the Valmiki reserve, which is why it is the most tempting wrong answer. Option C, the Gangetic dolphin, is the national aquatic animal of India and is protected in the Vikramshila sanctuary in Bhagalpur, but it is not the state animal. Option D, the sambar, is the large deer of the state's dry deciduous forests and has no symbolic status. Keep the national and the state lists apart: tiger and dolphin for India, gaur and house sparrow for Bihar.

The correct answer is A, tropical moist deciduous. West Champaran lies at the foot of the Shivaliks along the Nepal border and receives heavy rain, and its forest, in which sal is the dominant tree, is classed as tropical moist deciduous. The Valmiki Tiger Reserve lies in this belt. The trees shed their leaves in the dry months, which is what deciduous means, but the rainfall is high enough for the forest to be called moist.

Option B, tropical thorn, is the forest of dry regions such as western Rajasthan, with acacia and cactus-like growth, and has no place in Bihar. Option C, montane temperate, needs altitude, and Bihar's highest ground, Someshwar peak in the same district, is far too low for it. Option D, tropical evergreen, requires very heavy rain throughout the year, as in the Western Ghats and the north-east, and none of Bihar's forests qualifies. The contrast to carry into the exam is moist deciduous sal in Champaran and dry deciduous khair, palas and mahua on the Kaimur plateau.