soila & vegetaion types in tropics-ram19!04!12

7/31/2019 Soila & Vegetaion Types in Tropics-ram19!04!12

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by:Ramanujam.S

IN TROPICS

(India)


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Order Suborder GreatGroup Subgroup Family Series

To enable us systematic study of soilsTo determine the relationship between the different kinds of soils.To know how they can be best used.To estimate the productivity of soils under different managementpractices.

Purpose of Soil Classification

Soil ClassificationThere are six categories in the Soil Taxonomy

Modern system of soil classification

The soils in the world can be assigned to one of just 12 orders by

USDA system.Soil orders are frequently defined by a single dominantcharacteristic affecting soils in that location, e.g., the prevalentvegetation, the type of parent materialor the climate variables such aslack of precipitationor the presence of permafrostor the amount ofphysical and chemical weathering presentor the relative amount of

Soil Profile Development that has taken place.


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Soil orders Description

ALFISOLS Soils with a clayey B horizonFound in cool to hot humid areas, & in the semiarid tropics

ANDISOLS Form in volcanic ash and cinders near or downwind from volcanic activity.

Generally lacking in developmentARIDISOLS Soils of arid region, such as desert soils. Some are saline.

light in color, and low in organic matter content. Water deficiency is dominant characteristic

ENTISOLS Soils with little or no horizon development in the profile. mostly derived from alluvial materials.Occur in areas where a very dry or cold climate limits soil profile development.

GELISOLS Soils with permafrost within 2 M of the surface & have limited profile development.Large areas of this soil occur in Northern regions of Russia, Canada, and Alaska.

HISTOSOLS(marshy soil)

Soils rich in organic matter. Generally consist of at least half organic materials (by volume)Form in wetland areas of any climate where plants can grow such as bogs, marshes, and swamps,

MOLLISOLS Latin word mollis, meaning soft. These mineral soils have developed on grasslands, a vegetation thathas extensive fibrous root systems.

INCEPTISOLS Soils are in the beginning stages of soil profile development.Commonly found throughout world, and prominent in mountainous regions.

OXISOLS(weathered soil)

composed of highly weathered tropical & subtropical soils

formed in hot, humid climates that receive a lot of rainfall ,located in equatorial regions.

SPODOSOLS Form in sandy parent materials under coniferous forest vegetation.coarse texture, have a high leaching potential. associated with a cool and wet climate,

ULTISOLS They are acidic, leached soils from humid areas of the tropics and subtropics. Intensely weathered soils of warm and humid climates.

VERTISOLS(black soil)

Dark clay soils containing large amounts of swelling clay minerals (smectite).The soils crack during the dry season & become very sticky in the wet season.formed in warm, subhumid or semi-arid climates,

Table 1. Brief descriptions of the 12 soil orders according to Soil Taxonomy.


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Volcker (1893) and Reathee (1898), classified the Indian soils into4 groups

1.Indo-gangetic alluvium,2.Black cotton,3.Red and4.Laterite soils.

Major Soil Groups in India

Indian Council of Agricultural Research (ICAR) hasdivided Indian soils into eight major groups

Alluvial SoilsBlack soilsRed soils

Laterite soilsForest and Mountain SoilsArid and Desert Soils

Saline and Alkaline SoilsPeaty and Marshy Soils


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Geographical Situation

India has a geographical area of 327.4 million hectares. Sub-continent lies between 8o 37o north latitude and 69o- 93o

east longitude. Northern boundary of country has a chain of Himalayas

extending all along northern side, bordering Pakistanon westand Burmaon east.

Remaining south, east and west borders are surrounded by Indian

Ocean, Bay of Bengal' and Arabian searespectively.

Climate

Climate of India is of monsoon type.Two distinct periods of rainfall in a year, viz. the south-west monsoonduring

the months of June-September and the northeast monsoon during the wintermonths.Climate is influenced by the Himalayan mountains as well as the Indian ocean,the Arabian sea and Bay of Bengal.Temperature is equally variable like rainfall. Temperature rises continually during summer months (March to June).


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PhysiographyThe major physiographicdivisions of our country .

1.The Northern mountainsWestern & EasternHimalayas2.The great plains Indus plains, Ganga plainsand Brahmaputra Valley. Occur between the northernmountains and the peninsula.3.The PeninsulaConsists of central uplands,Deccan plateau, eastern

plateau western hills easternhills and coastal plains4.The islandsSmall in land area, consistof Arabian sea and Bay ofBengal islands.


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the largest and the most important soil group of India.Covers 40% of the land area.They are composed of sediments deposited by rivers and the waves.Their chemical composition makes them one of the most fertile in the world.

Usually deficient in nitrogen and humus (thus fertilizers are needed).In fact entire Northern Plains are made up of these soils.Brought down and deposited by three great Himalayan rivers- Sutlej, Gangaand Brahmaputra- and their tributaries.Through a narrow corridor in Rajasthan they extend into plains of Gujarat.Common in eastern coastal plains and in deltas of Mahanadi, Godavari,Krishna and Kaveri.

Alluvial Soil

Can be divided into old & newalluviumOld alluvium soil posses welldeveloped horizons.sub surface of soils

are reddish brown or grey brown sandyloam or loamy in texture& sub soilcontain more clay than surface soil.Texture of new alluvium is verycoarse on the river banks and very finein low lying marshy lands.


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These soils have been formed due to the solidification of lavaspread over largeareas during volcanic activity in the Deccan Plateau, thousands of years ago.Black due to compounds of iron and aluminum(because of titaniferousmagnetite).Mainly found in Deccan Plateau Maharashtra, Gujarat, M.P, Karnataka, AP, TNApart from cotton cultivation, these fertile soils are suitable for growing foodgrain, oilseeds, citrus fruits and vegetables, tobacco and sugarcane.They have high moisture retention level. Lack in phosphorus, nitrogen andorganic matter

Typical of Deccan trap (Basalt) region spread over north-west Deccan plateauand are made up of lava flows.Cover plateaus of Mahrashtra, Saurashtra, Malwa and southern MadhyaPradesh and extend eastwards along Godavari and Krishna Valleys.

Black Soil (ideal for cotton crop).

Can be divided into 3 Groups,Shallow black soil(depth 30-50cm),texture varies

from silty loam to loam & color that varies from darkyellowish brown to dark brownMedium black soil(depth50-120 cm),Deep black soil(depth above 120cm).texture inboth case varies from slity clay to clay. both contain40 to 60 % or more clay, color of these soils varies

from deep black to light black.


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Result of intense leaching owing to heavy tropical rains.Found in typical monsoon conditions under conditions of high temperatureand heavy rainfall with alternate wet and dry periods.

Found in parts of Western Ghats, Eastern Ghats, Rajmahal hills, Maharashtra,Karnataka, Kerala, Orissa, WB, Assam, Tamil Nadu, etc.Poor in nitrogen and minerals.Best for tea, coffee, rubber, coconut and suitable for rice and millet cultivationif manured.

Laterite Soil (Later means brick)

They are usually shallow and gravelly athigher lands, but are very deep loam toclay soils in valleys where good paddycrops are produces on them.

not sticky and plastic when wet.Excellent physical condition due topresence of hydrous oxides of iron andaluminum & kaolinite as the dominatingclay minerals.


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Cover nearly 14% of total area, such soils are mainly found on the hill slopescovered by forests.The formation of these soils is mainly governed by the characteristic depositionof organic matter derived from forest growth.In the Himalayan region, such soils are mainly found in valley basins,depressions and less steeply inclined slopes. Apart from the Himalayan region, the forest soils occur in higher hills in southand the peninsular region.Very rich in humus(by fallen leaves) but are deficient in Potash, phosphorousand lime and needs fertilizers.Plantation of tea, coffee, spices and tropical fruits.Developed from acidic parent material, are poor in basic elements

Forest and Mountain Soils

Saline and Alkaline Soils

In the drier parts of Bihar, Up Haryana, Punjab, Rajasthan andMaharashtra, are the salt-impregnated or alkaline soils.Some of the salts are transported in solution by the rivers and canals,which percolates in the sub-soils of the plains.Accumulation of salts makes soil infertile and renders it unfit for agriculture


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A large part of the arid and semi-arid regionin Rajasthan and adjoiningareas of Punjab and Haryana lying between the Indus and the Aravallisreceiving less than 50 cm of annual rainfall is affected by desert conditions.

This area is covered by a mantle of sand which inhibits soil growth.The phosphate content of these soils is as high as in normal alluvial soils.Nitrogen is originally low but its deficiency is made up to some extent by theavailability of nitrogen in the form of nitrates.Thus the presence of phosphates and nitrates make them fertile soilswherever moisture is available.

Arid and Desert Soils

Peaty and Marshy Soils

Originate in the humid regions as a result of accumulation of largeamounts of organic matter in the soil.

They contain considerable amounts of soluble salts and 10 40% oforganic matter.Peaty soils are found in Kottayam and Alappuzha districts of Kerala,where it is called Kari.Marshy soils, high in vegetable matter, are found in northern Bihar, coastalparts of Orissa, Tamil Nadu and West Bengal and parts of UP


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Some of the tropical soils are considerably different from temperate regionsoils because the clays are mainly hydrous oxidesinstead of the temperatesilicates clays, thus the properties of hydrous oxides require different

techniques in soil management.Hydrous oxide clays have a very low capacity to hold nutrients so requirecontinual frequent renewal of nutrients by additions for adequate plant growth.The low capacity to hold nutrients also requires careful use of lime, as overliming can easily occur resulting in certain nutrient deficiencies or toxicities.An advantage of hydrous oxides is their ability to be worked shortly after a

rain.Most silicates clay minerals become very sticky when wet, whereas thehydrous oxides can be worked within a few hours after a rain.Often weather condition of high temperature and abundant rainfallresult intropical rain forest.The soils developed under these conditions are highly weathered andmuch of the nutrients have been leached to lower layers within the soil.

General properties


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Soil order TropicalAfrica

Tropical Asia TropicalAmerica

Total Percent

Humid

Tropics1)

Oxisols 179 14 332 525 35

Ultisols 69 131 213 413 28Alfisols 21 15 18 54 4

Others 176 219 103 498 33

Total 445 379 666 1490 100

Semi-arid

Tropics2)

Alfisols 466 121 107 694 33

Ultisols 24 20 8 52 1

Others 972 178 198 1348 66

Total 1462 319 313 2094 100

Table 3. Geographical distribution of soils in the humid and semi-arid tropics (millions ofhectares).1) Data from NAP (1982).2) Data adapted from Kampen and Burford (1980). Part of the subhumid tropics is included


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Types of vegetation in India vary depending upon environment, Climate,soil quality, topography and altitude.These factors are responsible for natural diversity in forests

There are several types of forests scattered throughout Indianlandscape. Primarily there are 6 major groups, namely,

Vegetation classification

Moist Tropical,Dry Tropical,

Montane Sub Tropical,Montane Temperate,Sub Alpine,Alpine.


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A. Most Tropical Forests:They are divided into 4 groups and each group is further sub-divided into sub-groups which in turn are further splits into formations and associations.

Tropical Wet Evergreen Forest:Such forests found in regions with rainfall over 2500 mm per annum, mostly inwestern Ghats and along south west of Assam. sal are the main trees.

Torpical Semi-Evergreen Forests:

This is found along the Western Ghats adjoining wet ever green forests i.e., inAssam and lower attitudes of Eastern Himalayas, Orissa, Malabar Coast andAndaman's. Rainfall varies from 200-2500 mm.

Tropical Moist Deciduous Forests:This type of forest is found in typical rainfall range of 1500-2000mm.

In U.P., Bihar, Orissa, North Bengal. Maharashtra, Madhya Pradesh,Karnataka, Tamil Nadu. And Kerala etc.These areas are characterized by most teak forests.


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Littoral and 'Swamp ForestsThese are further subdivided into two subgroups:(a) The littoral forests(b) The tidal swamp forests(a) The littoral forests occur all along the sea coasts and along the sandybars of deltas of the larger rivers.(b) The tidal swamp forests are further divided into 5 types:(i) Mangrove scrub, (ii) Mangrove forests, (iii) Salt water mixed forests, (iv)Brakish water mixed forests and (v) Palm swamp.The Sunder bans (W.B.) and the Bhitar Kanika (Orissa) mangrove forestscome under this category.

B. Dry Tropical Forests:They are divided into three groups:Tropical dry Deciduous Forests:All the forests of North India i.e., Bihar, U.P., Punjab, Haryana of non-teak

and teak bearing types come under this.Tropical Thorn Forests:These are distributed in areas of low rainfall (250-750 mm per annum) inboth southern and Northern regions of India i.e., Punjab, Haryana,Rajasthan, U.P., M.P., Maharashtra, A.P. etc.Tropical Dry Evergreen Forests:

These are dense forests of coniferous leaved evergreen forests.


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C. Montane Subtropical Forests:These are further divided into three groups.1. (i) Subtropical Broad leaved hill forests :

(a) Nigeria Subtropical hill forests(b) South Indian subtropical Hill savannah(c) Reed brakes(d) Western subtropical hill forest(e) Central Indian sub-tropical Hill Forests.(ii) Northern subtropical Broad-leaved hill forests:

(a) East Himalayan Sub-tropical wet hill forests(b) Khasi sub-tropical wet Hill forests(c) Assam subtropical pine forests(d) Assam subtropical Hill Savannah2. Sub-tropical pine Forests:These are found in U.P., H.P. and Assam through out the entire contour of the

western and central Himalayas.3. Sub-tropical Dry Evergreen Forests:Those forests contain small leaved evergreen trees and shrubs including somethorn species.


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D. Montane Temperate Forests:They are divided into three groups:Montane Wet Temperate Forest:This type occurs in the east Himalayas from East Nepal to Bengal, Assam .

Himalayas Moist Temperate Forests:These forests occur above 1,500 M & extended up to 3,000 metersin thewestern and central Himalayas.Himalayan Dry Temperate Forest: These are open forest composed ofevergreen conifers and some broad leaved trees. They occur above 1700 m

E. Sub-alpine Forests:These forests occur in Jammu and Kashmir, Himachal Pradesh, UttarPradesh, Bengal, Assam and Manipur, They occur at an altitudinal range of2,900 m to 3,500 m.

F. Alpine Scrub Forest:

These forests extent from 3,600 mtrs. Above. They are well distributed inKashmir, West Kumauni in UP and along western Himalays from 2,900 mtrs. to4,250 mtrs.


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Tropical moist forests-33.92%Tropical dry forests-30.16%,Tropical evergreen-12.39%

Montane temperate-7.52%Sub tropical -6.73%Tropical thorn -5.11%Alpine & sub alpine-3.79%Swamp ( mangrove)-0.38%

Forest cover

Distribution of Soils in India


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Sl.No Soil groups Area (M.ha) Distribution in the states

1 Red loamy 21.3 AP, TN, KT, KR, MP, O, R2 Red sandy 33.0 TN, KT, AP, B, WB3 Laterite 13.0 TN, KR, KT, AP, GJ, O, M, G, A, WB, AN4 Red & yellow 40.3 MP, O, B

5 Shallow black 3.1 M6 Medium black 43.0 M, MP, GJ, AP, KT, R7 Deep black 11.2 M, AP, KT, MP, GJ, R8 Mixed red & black 16.2 KT, TN, M, MP, AP, B9 Coastal alluvium 5.4 TN, KR, KT, AP, M, G, WB, AN10 Coastal sands 0.45 O, TN, AP, PO11 Deltaic alluvium 8.70 TN, AP, O, WB

12 Alluvial (Recent & old) 35.67 UP, P, B, WB, A, H, AP, GJ, JK, HR, MP, R, D13 Alluvial (Calcareous) 1.3 UP, B14 Calcareous sierozemic 4.5 P, H, R15 Grey brown 10.1 GJ, R16 Desert 18.2 R, G, H17 Tarai 2.8 UP, B, WB, AN18 Brown hill 8.1 UP, S, HP, GJ, JK, KR, P, WB

19 Sub montane 7.6 UP, JK, HP20 Mountain meadow 5.9 JK21 Saline and alkali 1.7 UP, H, P, M, KR, TN, GJ, R22 Peaty 0.27 KR, WB23 Skeletal 7.9 MP24 Glaciers & eternal

snow2.9 UP, JK

25 Others 24.9 -

Distribution of Soils in India

Symbols for states- AN-Andaman & Nicobar islands; AP Andhra Pradesh; A-Assam; B-Bihar; D-Delhi; G-Goa; GJ-Gujarat; H-Haryana; HP-Himachal Pradesh; JK-Jammu & Kashmir; KT-Karnataka; KR-Kerala; MP-Madhya Pradesh; M-Maharashtra; O-Odhisa; PO-Pondicherry; P- Punjab; R-Rajasthan; TN- Tamil Nada; UP-Uttar Pradesh; WB- West Bengal.


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Basic concepts of soil science by A.K.KolayHand book of soils for landscape architects by robert f.keefer

http://www.indianetzone.com/40/natural_vegetation_india.htmhttp://www.mapsofindia.com/andaman-nicobar-islands/geography-and-history/soil-vegetation.htmlhttp://en.wikipedia.org/wiki/Tropical_Rainforest_of_India

http://india-garg.blogspot.in/http://www.preservearticles.com/201107058730/classification-of-indian-forest-types.html

Bibliography

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soila & vegetaion types in tropics-ram19!04!12

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