Soils of Odisha

Soils of Odisha: Odisha, located on the eastern coast of India, is a region known for its diverse topography, rich natural resources, and varied climatic conditions. These factors contribute to the state’s diverse soil types, which play a crucial role in supporting its agricultural economy. From the fertile alluvial soils in the coastal plains to the lateritic and red soils in the upland areas, Odisha’s soils exhibit significant variation, both in terms of composition and fertility. The state’s agrarian communities depend heavily on these soils for the cultivation of crops like rice, pulses, and oilseeds, making soil health a critical aspect of regional food security and rural livelihoods. Understanding the characteristics, distribution, and management of these soil types is essential for sustainable agricultural practices, environmental conservation, and enhancing the productivity of Odisha’s land resources. This note delves into the different soil types found in Odisha, their geographical distribution, and their implications for agriculture and land management.

Classification of Soils in Odisha

The soils of Odisha can be categorized into two main groups: based on their formation and based on relief features.

Classification Based on Formation

Under this classification, Odisha’s soils are divided into two types:

1. Transported Soils: These soils are composed of a mix of eroded materials carried from different locations, resulting in a heterogeneous nature.
2. Residual Soils: Formed through the action of various erosional agents, these soils are typically found in interfluves, mountains, and plateaus across Odisha.

Classification Based on Relief Features

According to relief features, Odisha’s soils are divided into the following eight major groups:

1. Red Soil
2. Laterite Soil
3. Red and Yellow Soil
4. Coastal Saline and Alluvial Soil
5. Deltaic Alluvial Soil
6. Black Soil
7. Mixed Red and Black Soil
8. Brown Forest Soil

Red Soil

• This soil is formed from the iron deposits of the upper Dharwar series through the decomposition of silicates during rainfall. It is characterized by a coarse texture and a surface layer with a single-grained to weakly granular structure.
• Highly porous with a low water-holding capacity, this soil covers approximately 7.14 million hectares, making it the most widespread soil type in the state.
• Red soil is prevalent in the districts of Koraput, Rayagada, Nabarangpur, Malkangiri, Keonjhar, Ganjam, Kalahandi, Nuapada, Balangir, Dhenkanal, and Mayurbhanj in Odisha.
• It is non-saline, with its red color attributed to the presence of iron oxides. The soil is moderately acidic and generally lacks nutrients such as nitrogen, organic matter, and molybdenum.
• Unlike laterite soil, red soil contains a higher percentage of silica and some bases.
• This soil supports the cultivation of crops such as rice, finger millets, minor millets, potatoes, brinjal, and fruit trees like mango, jackfruit, guava, papaya, and sapota.

Red and Yellow Soil

• These soils are found in undulating and rolling terrains, varying in depth, texture, and color.
• Covering approximately 5 million hectares, these soils constitute the second-largest soil group in Odisha, predominantly found in the districts of Sambalpur, Bargarh, Deogarh, and Sundargarh.
• They are classified into two types: upland soils and lowland soils. Upland soils are coarser in texture, with red to yellowish-red colors, shallow depth, and well-drained properties. They tend to be more acidic than the soils in the lower areas.
• Lowland soils, on the other hand, are formed from alluvial deposits and have a finer texture. Their colors range from pale yellow to greyish and olive shades. These soils often exhibit mottling (irregular color patches) due to seasonal submergence during the monsoon and subsequent drying.
• Crops cultivated in upland soils include rice, finger millet, sugarcane, potato, brinjal, and tomato. In the lowland soils, paddy, pulses, and fruit trees such as mango, guava, and banana are commonly grown.

Black Soil

• Black soils are formed through the weathering of basic rocks in low-lying regions, shaped by specific lithological and topographical conditions.
• These soils cover around 0.96 million hectares and are found sporadically in the districts of Puri, Ganjam, Malkangiri, Kalahandi, Nuapada, Balangir, Sonepur, Boudh, Sambalpur, Bargarh, and Angul.
• In the summer, black soils develop deep and wide cracks. Their pH ranges from 7.5 to 8.5, indicating a slightly alkaline nature. The soil has a clay texture with an angular blocky structure.
• Black soils are low to moderate in nitrogen and potassium content. Their distinctive black color comes from the presence of titaniferous magnetite, humins, and bitumens.
• Common crops cultivated in black soil include rice, jowar, bajra, maize, Bengal gram, sunflower, mustard, and cotton.

Laterite Soil

• Laterite soils form in hot, wet tropical areas and are rich in aluminum, manganese, and iron.
• In Odisha, laterite soils are found on high-level plateaus and hilly areas, particularly in regions with high rainfall. They are well-developed in the Eastern Ghats and cover approximately 0.70 million hectares in the districts of Puri, Khurda, Nayagarh, Cuttack, Dhenkanal, Keonjhar, Mayurbhanj, and Sambalpur.
• Highly permeable, laterite soils are poor in essential nutrients like nitrogen, phosphorus, potassium, and calcium, and are generally acidic.
• Groundnut, pulses, rice, finger millet, minor millet, sesame, potatoes, vegetables, and fruits like mango, jackfruit, banana, guava, and sapota are grown in this soil.

Deltaic Alluvial Soil

• The texture of deltaic alluvial soil ranges from coarse sand to clay, depending on the geomorphology of the floodplain and the type of alluvium deposited by river water. The structure of this soil is granular.
• These soils cover an area of 0.67 million hectares and are found in the districts of Balasore, Bhadrak, Jajpur, Kendrapara, Jagatsinghpur, Cuttack, Puri, Gajapati, and Ganjam.
• The soil types vary from north to south as follows:

1. North Balasore Region: Sandy or sandy loam soil.
2. Delta of Baitarani and Brahmani: Clay loam to stiff clay.
3. Delta of Mahanadi: Stratified into clay and silt sand.
4. Rushikulya Delta: Predominantly sandy in nature.

• These soils are generally fertile, but there are areas with low nitrogen and phosphorus content. The fertility decreases if the soils are not regularly replenished by flooding. Major crops grown include rice, groundnut, mustard, sesame, potato, black gram, and various vegetables.

Coastal Saline and Alluvial Soil

• These soils contain high levels of soluble salts due to the intrusion of salty tidal water from the sea through creeks.
• They contain salts such as chlorides and sulfates of sodium, magnesium, and, to a lesser extent, calcium and potassium.
• Found along the coastal belt of the state, these soils extend 5-25 km inland and cover 0.254 million hectares. They are present in the districts of Balasore, Bhadrak, Jagatsinghpur, Kendrapara, Puri, Khurda, and Ganjam.
• The texture ranges from clay to clay loam, with a columnar structure. Soils around Chilika Lake are also affected by salts due to flooding from the lake during monsoon.
• Important crops grown in these soils include rice, mustard, barley, linseed, chili, sugar beet, tomato, spinach, and cotton.

Brown Forest Soil

• Found in forested regions, covering an area of 0.17 million hectares in the districts of Phulbani, Kandhamal, Rayagada, and parts of Ganjam and Nayagarh.
• This soil is brown to grey-brown in color, has a light texture, and is acidic in nature.
• It contains medium to high levels of organic matter and nitrogen, with medium phosphorus and potash content.
• Important crops grown in these soils include maize, tapioca, wheat, mustard, and horticultural crops like jackfruit, mango, guava, and citrus fruits.

Mixed Red and Black Soil

• This soil is a combination of both red and black soils, where black soil appears in patches within the predominantly red soil. The two types are intermixed, with red soil typically found in higher areas and black soil in lower regions.
• This soil type covers an area of 0.16 million hectares and is found in the western districts of Sambalpur, Bargarh, Sonepur, and Balangir. The texture ranges from light to medium, with black soil rich in calcium and red soil rich in iron, creating a catenary formation.
• Key crops grown in these soils include rice, sugarcane, maize, ragi, groundnut, sesame, and various vegetables.

Problems and Management of Soils in Odisha

The problem soils of Odisha can be classified into three main categories:

1. Low Fertile Acidic Soils

• This category mainly includes red and lateritic soils, which make up about two-thirds of the total land area in Odisha. These soils are characterized by high permeability and a tendency to lose moisture quickly, making them highly susceptible to droughts, especially during periods of frequent dry spells in the rainy season.
• To improve the fertility and manage the acidity of these soils, the application of organic manures and lime is recommended. Organic manures help enhance the soil structure and water retention, while lime neutralizes the soil’s acidity, making it more suitable for agricultural use.

2. Lowland Soils with Iron Toxicity Problems

• These soils are typically found on valley slopes and toe-slope lands, where they are affected by the accumulation of lateritic materials rich in iron due to water seepage. This iron accumulation can lead to toxicity, which adversely impacts plant growth and crop yields.
• Effective management of these soils involves improving drainage facilities by constructing deep drains around the fields to remove excess water. Additionally, building check embankments across slopes can help control lateral seepage, thereby reducing iron toxicity and creating a more favorable environment for crops.

3. Coastal Salt-Affected Soils

• These soils are found along the coastal regions of Odisha and are characterized by high salt content, which can inhibit plant growth. During the rainy season, heavy rainfall can help dilute and flush out some of the salts through leaching, temporarily lowering their concentration.
• To manage these soils, it is crucial to apply appropriate soil nutrients and avoid leaving the land fallow, which can increase salinity levels. Growing salt-tolerant crops and using proper irrigation practices can also help in maintaining soil health and improving agricultural productivity in these areas.

Conclusion

The diverse range of soils in Odisha, including deltaic alluvial, coastal saline, red and black, lateritic, and problem soils, reflects the state’s varied geographical and climatic conditions. Each soil type presents unique characteristics and challenges, from the fertile alluvial plains supporting rich agricultural diversity to the acidic and salt-affected soils that require careful management. Understanding these soil types and implementing appropriate soil management practices—such as the use of organic manures, lime, and proper drainage systems—can significantly enhance agricultural productivity. With a focus on sustainable soil management, Odisha has the potential to optimize its land use, improve crop yields, and strengthen food security for its population.