2. New System of Classification
3. Aridsols order of Soils
4. Alfisols order of Soils
5. Entisols order of Soils
6. Inceptisols order of Soils
7. Vertisols order of Soils
8. More in Soils
9. Reference Articles / Books
Soil is one of the most important natural resources as mankind is dependent on soil for food. Soil, the top-most layer of earth crust, is a mixture of organic matter, minerals, gases, liquids, and organisms that together support life. The soils of Rajasthan have developed under the arid and humid climate over the bed rocks of complex nature predominately through the process of Laterization.
The tints, chemical composition, texture, structure, reaction, and plant food contents bear large scale as well as local variations, according to environments. By considering all these factors, the soils of Rajasthan is classified into two system –
- Old System of Soil Classification
- New System of Soil Classification
- A new comprehensive system of soil classification was developed by Soil Survey Staff in 1976.
- This new system has 10 soil orders, which are subdivided into 47 suborders and then 230 great groups. These great-groups are then subdivided into family and series.
- Under the new system, most soils of Rajasthan belong to only 5 orders, which are further classified into sub-orders and great-groups as mentioned below:
- Inceptisols and
- These soils occur extensively in the western half of Rajasthan divided by the Aravalli axis and some parts of Alwar, Jaipur and Ajmer districts which fall on the eastern half.
- Aridisols are mineral soils mostly found in dry climatic regions.
- Aridisols are associated with soils of order Entisols.
- Major portion of Aridisols in Rajasthan is covered by the suborder Orthids.
- The soils of suborder Orthids commonly have horizons of accumulation of soluble salts and carbonates.
- The following four great-group under this subgroup ‘Orthids’ are found in the Rajasthan –
[a] Camb-orthids –
- The soils of this great group occur in parts of Jalore, Churu, Jodhpur, Pali, Barmer, Sikar and Jhunjhunu districts.
- These are associated with calciorthids.
- These are brownish to reddish in colour.
- These are youngest of aridisols.
[b] Calci-orthids –
- These soils occur in parts of Jalore, Jodhpur, Pali, Barmer, Nagaur, Churu, Sikar, Junjhunu, Shiganganagar and Hanumangarh districts.
- The Calciorthids occur in the range of 100 to 500 mm rainfall range in the state.
- The Calciorthids recognized in this region are mostly Typic.
- These soils are coarse loamy or fine loamy.
[c] Sal-orthids –
- These soils occur in the small patches in the Ghaggar Flood plain in Shri Ganganagar districts.
- These soils are also found near the salt lakes in Rajasthan.
- These are salty soils of wet places in deserts.
- Vegetation is sparse and consists of salt tolerant grasses and shrubs.
[d] Pale-orthids –
- These soils occur in small patches around Jaisalmer, Barmer and Nagaur.
- These soils have a petrocalcic horizon, very close to surface and quite thick.
- Such soils generally occur on gentle slopes that have been stable for long periods.
- They are calcareous throughout and their color changes from reddish brown to nearly white.
- Alfisols soils occur in the parts of Jaipur, Alwar, Bharatpur, Sawai Madhopur, Tonk, Bhilwara, Chittorgarh, Banwara, Udaipur, Dungarpur, Bundi, Kota and Jhalawar districts.
- These are mature soils with medium to maximum profile development.
- The Most of the area covered under Alfisols in Rajasthan comes under only one suborder – ustalfs and one great group – Haplustalfs.
[a] Haplustalfs –
- These soils are reddish to brownish in color.
- The average annual rainfall in this region is 500 to 900mm.
- Entisols are dominant soil of the state. All districts in western half are covered in some or major part by these soils.
- Entisols lack well developed horizons and have minimum profile development.
- In Rajasthan, important suborders are: Psamments and Fluvent, which are further divided into four great-groups –
[a] Torripsam –
- These soils occur on sand dunes and in flood plains.
- These soils are characteristically of arid climate. So, these have lower water holding capacity.
- Vegetation consists of a few ephemeral plants.
- These soils occur in the low rainfall region i.e. 10-50cm.
[b] Quartzipsam –
- These soils occurring on the western border of the state covering small parts of Barmer and Jaisalmer districts.
- These soils occur in the very low rainfall region i.e. 10-20cm.
[c] Torrifluvents –
- These Soils occur with Calciorthids and Salorthids in the Ghaggar area of Sriganganagar district.
- These are mostly alkaline or calcareous and generally saline under natural conditions.
- The annual rainfall does not exceed 300 mm in these parts.
[d] Ustifluvents –
- These Soils occur in the north-eastern and eastern prtion of the state covering parts of Alwar and most of the Bharatpur district.
- These soils show irregular distribution of organic carbon calcium clay and slit.
- The annual rainfall in his area is 500-650cm.
- Inceptisols occupy a major area along the foothills of the Aravalli in the districts of Sirohi, Pali, Udaipur, Bhilwara, Chittorgarh and in some parts of alluvial plains in Udaipur, Alwar, Sawai Madhopur and Jhalawar.
- The Most of the area covered under Inceptisols in Rajasthan comes under only one suborder – Ochrepts and one great group – Ustochrepts.
[a] Haplustalfs –
- These soils are reddish and brownish in color.
- They are generally calcareous and shallow to deep.
- Vertisols soils cover the large area of Jhalawar, Kota, Bundi and small part of Sawai Madhopur, Bharatpur, Dungarpur, Chittorgarh and Banswara districts.
- They are clayey soils that develop deep wide cracks when dry and become sticky & plastic when wet.
- They are compact and very slowly permeable in the lower layer.
- These Soils of Rajasthan come under sub-order of Usterts and associated with two great-groups.
[a] Chromusterts –
- These soils occur in parts of Bundi, Kota and Jhalawar districts of south-eastern states and to a little extent in Chittorgarh, Dungarpur, Banswara and Bharatpur districts.
[a] Pallusterts –
- These soils occur in parts of Bundi, Kota, Jhalawar, Chittorgarh, Dungarpur, Banswara and Bharatpur districts.
- These soils are dominantly gray to black and occur in level plains and depressions.
Approximate Equivalents of Old and New system of Soil Classification
|Order||Sub Order||Great Group||Approximate Equivalent in the old system|
|Sierozems, Desert Soils, Saline Soils|
|Alfisols||Ustalfs||Haplustslfs||Red Loam, Black Soil, Brown Soils, Yellowish brown Soils of foot hills, Alluvial Soils|
|Deset Soils, Sand Dunes, Alluvial Soil|
|Inceptisols||Ochrepts||Ustochrepts||Brown Soils, Red and Yellow soils of foot hills|
- Cotemporary Rajasthan by Dr. L. R. Bhalla & others
- Lakshya Rajasthan 2016 by Mahaveer Jain & others
- Soils at Wikipedia