Soils of Odisha: In Odisha, the state has been divided into ten agroclimatic zones, considering various factors such as landform, topography, climate, soil, and crop adaptability. This zoning helps in understanding the unique agricultural characteristics and challenges in different regions of the state. By considering the specific conditions of each agroclimatic zone, appropriate farming practices and crop choices can be recommended to optimize agricultural productivity.
Odisha’s soils have been categorized into eight major soil groupings based on their characteristics and properties. These soil groupings are further classified taxonomically into four orders, ten suborders, and eighteen large groups. This classification system provides a systematic understanding of the diversity and distribution of soils within the state.
Each soil type in Odisha is associated with distinct characteristics, strengths, and limitations that influence agricultural productivity. Some of the major soil groupings in the state include red soils, laterite soils, alluvial soils, black soils, sandy soils, and saline and alkaline soils. These soils vary in their texture, fertility, drainage capacity, nutrient content, and water-holding capacity.
Understanding the specific characteristics and issues related to each soil type is crucial for addressing the challenges that may limit agricultural productivity. For example, red soils are known for their fertility and suitability for a wide range of crops, but they can be prone to erosion and have lower water-holding capacity. Laterite soils, rich in iron and aluminum, are suitable for certain crops but require proper management to address their low fertility and drainage limitations.
Recognizing the importance of these soil characteristics and issues, efforts are being made to give more attention to soil management practices in Odisha. This includes measures such as soil conservation, organic matter addition, appropriate irrigation techniques, nutrient management, and crop rotation. By addressing the specific challenges associated with each soil type, farmers can optimize agricultural production, improve soil health, and sustainably utilize the land resources available to them.
Additionally, research and extension services in Odisha are actively working to provide farmers with tailored recommendations and guidance based on the specific agroclimatic zones and soil types. This helps farmers make informed decisions about suitable crops, agronomic practices, and soil management techniques that can enhance productivity and reduce the negative impacts on the environment.
By recognizing and addressing the unique characteristics and challenges of different soil types in Odisha, the aim is to promote sustainable and efficient agricultural practices that lead to increased productivity, improved soil health, and better livelihoods for farmers in the state.
Table of Contents
The following sections explain the characteristics of each soil type and their management strategies.
Red Soil
Red soil, the most extensive soil group covering approximately 7.14 million hectares of land in Odisha, is predominantly found in districts such as Koraput, Rayagada, Nawrangpur, Malkangiri, Keonjhar, Ganjam, Kalahandi, Nuapada, Bolangir, Dhenkanal, and Mayurbhanj. The characteristic reddish hue of these soils is attributed to the presence of elevated levels of iron oxides.
The texture of red soils varies within different districts. The first four districts mentioned have a coarser texture, while the remaining districts possess a finer texture. The soil particles are typically angular or subangular in shape, and the soil structure is blocky. The clay fraction of these soils is dominated by kaolinites and illites.
Red soils in Odisha are generally characterized by a strongly to moderately acidic pH. They have a low to moderate organic matter content and a limited capacity to retain water. These soils are deficient in nitrogen and phosphorus, and they particularly lack boron and molybdenum. They exhibit a limited capacity for cation exchange, a high capacity for phosphate and sulphur absorption, and deficiencies in calcium and magnesium. Soluble phosphates in water become fixed in these soils, rendering them unavailable for uptake by agricultural plants.
To maximize phosphate utilization, it is recommended to apply insoluble phosphates or a combination of insoluble rock phosphates and single super phosphate in equal proportions (1:1) two weeks prior to sowing. Lime can be used to balance the soil acidity, with an application rate of 1 to 2 tonnes per hectare of paper mill sludge being effective in this regard. Winter vegetables and groundnut crops benefit from the application of ten to fifteen kilograms of borax per hectare. Seed treatment with sodium molybdate at a rate of 10 grams per 25 kilograms of seeds corrects molybdenum deficiency in pulses and groundnut crops. Phosphogypsum, applied at a rate of 200 kilograms per hectare, meets the sulphur requirements of oilseed crops.
Red soils in Odisha support the cultivation of various crops. Rice, finger millet, minor millets, niger, potato, and brinjal (eggplant) are among the crops effectively grown in these soils. Additionally, fruit trees such as mango, jackfruit, guava, papaya, and sapota (chikoo) thrive in red soil regions of the state.
Mixed Red and Yellow Soil
According to the latest data, the mixed red and yellow soils cover approximately 5.5 million hectares of land in Odisha, making them the second-largest soil group in terms of area. These soils are predominantly found in the districts of Sambalpur, Bargarh, Deogarh, and Sundargarh.
The mixed red and yellow soils are associated with catenary associations and occur in undulating and rolling terrains. They exhibit variations in depth, texture, and color. These soils are relatively shallow and have a gritty texture. In upland areas, the soils are shallower and lighter in texture compared to the lowland regions. The mixed red and yellow color of the soil is attributed to the presence of ferruginous concretions and fluctuations in the water table.
In terms of soil acidity, upland soils are moderately acidic, while lowland soils are somewhat acidic. Upland soils are generally deficient in nitrogen and phosphorus, whereas lowland soils are deficient in phosphates but abundant in potassium. Boron deficiency is observed in upland soils with a light texture, while zinc deficiency is more prevalent in lowland soils with rice-rice cropping systems in the Hirakud command area.
To address soil acidity, liming can be employed as a corrective measure. Upland soils support the cultivation of various crops such as rice, finger millet, sugarcane, potato, brinjal (eggplant), tomato, and pointed gourd. On the other hand, lowland fertile soils are particularly suitable for paddy (rice), pulses, and pyra crops. Fruit trees such as mango, guava, and banana thrive well in these mixed red and yellow soils.
Black Soil
According to the latest data, black soils are not found consistently throughout the state of Odisha. However, they occur intermittently in districts such as Puri, Ganjam, Malkangiri, Kalahandi, Nuapada, Bolangir, Sonepur, Boudh, Sambalpur, Bargarh, and Angul, covering an area of approximately 0.96 million hectares of land.
Black soils owe their characteristic color to the presence of titaniferous magnetite, humins, and bitumins. These soils are formed through the weathering of basic rocks in low-lying areas. They have a coarser texture and contain over 30% clay. The dominant clay minerals in these soils are smectites, which exhibit extensive cracking during the summer season. The effective soil depth exceeds 90 cm, allowing for sufficient root development. When wet, black soils swell to their maximum capacity, retaining a significant amount of moisture. However, their limited permeability contributes to surface soil erosion.
The pH of black soils ranges from neutral to alkaline due to the presence of free calcium carbonate nodules in the soil profile. Calcium is abundant in these soils, but they are deficient in phosphorus, potassium, zinc, and boron. Upland rice cultivated in black soils often experiences iron deficiency. Sulphur has been reported to be beneficial for crops such as groundnut, mustard, and safflower. Ammonia volatilization is higher in paddy fields grown in black soils.
Managing black soils can be challenging, especially under conditions of moisture stress and drought. Plowing these soils is difficult under both low and high moisture levels, highlighting the importance of proper soil moisture management. Tillage activities should be carried out at the appropriate moisture level to avoid soil compaction. Green manuring and the application of bulky organic manures can enhance water infiltration rates in these soils. Recycling rice straw improves soil aggregability.
Various crops thrive in black soils. Rice, jowar, bajra, maize, Bengal gram, safflower, mustard, and cotton are well-suited for cultivation in these soils.
Laterite Soil
Lateritic soils are found across approximately 0.70 million hectares of land in several districts of Odisha, including Puri, Khurda, Nayagarh, Cuttack, Dhenkanal, Keonjhar, Mayurbhanj, and Sambalpur.
These soils are characterized by their compact vesicular structure and are rich in hydrated iron and aluminum oxides, as well as trace amounts of manganese, titanium, and quartz. In some degraded laterite structures, a honeycomb-like appearance can be observed, particularly in the districts of Khurda and Cuttack. The texture of lateritic soils ranges from loamy sand to sandy loam, and there is often a hard clay pan in the subsurface. Upland laterite soils are prone to crusting issues.
Lateritic soils tend to be somewhat acidic to strongly acidic, with a pH ranging from 4.5 to 5.8. They are deficient in fertility and have a low organic matter content. Nitrogen and phosphate availability is typically poor, while potash availability is moderate. Nitrogen is susceptible to leaching, while phosphate becomes unavailable due to fixation by iron and aluminum oxides. These soils have a low capacity for cation exchange and a low percentage of base saturation. Sulphur is absorbed in the form of pyrites or zinc sulphide through the soil.
Proper soil management practices are essential to cultivate crops successfully in lateritic soils. Lime application helps to neutralize the acidity, while organic manure can improve soil fertility. Growing green manure crops and applying balanced fertilizers, along with the addition of paper mill sludge at a rate of 1 to 2 t/ha, can further enhance soil conditions. Groundnuts and pulses can be cultivated effectively in these acidic soils, while potatoes and other plants can grow well without liming.
Combining water-soluble and insoluble phosphatic fertilizers can increase crop yields in lateritic soils. Amendments with boron and seed treatment with molybdenum have been found to improve legume yields. Various crops, including rice, finger millet, minor millets, and sesame, thrive when provided with proper fertilization. Fruit trees such as mango, jackfruit, banana, guava, and sapota also thrive in lateritic soils.
Deltaic Alluvial Soil
Deltaic alluvial soils, covering approximately 0.67 million hectares of land, are primarily found in the deltaic sections of rivers such as the Mahanadi, Brahmani, Baitarani, Subarnarekha, and Rushikulya. These soils are distributed across districts including Balasore, Bhadrak, Jajpur, Kendrapara, Jagatsinghpur, Cuttack, Puri, Gajapati, and Ganjam.
The texture of deltaic alluvial soils ranges from coarse sand to clay, largely influenced by the geomorphology of the floodplain and the type of alluvial materials carried by river water. These soils can exhibit either a granular or platy structure, with the latter type being more challenging to work with. Clayey alluvial soils tend to crack when dried and become sticky when wet, making it difficult for plows to penetrate and work the soil. The clay particles have a high water-retaining capacity, resulting in prolonged waterlogging and delayed plowing. Drainage is often problematic due to the limited permeability of the soil.
Deltaic alluvial soils are generally productive, particularly when regularly recharged by floodwaters. However, fertility can decline if the soil is not replenished by floods. The pH of these soils can vary from acidic to neutral. Coarse-textured alluvial soils are typically deficient in nitrogen, phosphorus, potassium, and sulfur.
In the kharif season (monsoon season), deltaic alluvial soils are highly suitable for rice cultivation. The abundance of water and fertile soil support optimal rice growth. During the Rabi season (winter season), these soils are suitable for cultivating crops such as peanuts, mustard, sesame, potatoes, and various vegetables. Groundnuts, greengram, and blackgram can be cultivated successfully, utilizing residual soil moisture.
Coastal Saline Soil
The coastal region of Odisha is characterized by a group of soils known as saline soils, which have a high concentration of total soluble salts (EC > 4 dS/m). These soils are found in a narrow strip extending 5–25 kilometers inland from the sea and cover over 0.254 million hectares in districts such as Balasore, Bhadrak, Jagatsinghpur, Kendrapara, Puri, Khurda, and Ganjam. Salinity in these soils is primarily caused by the incursion of brackish tidal water from the sea through creeks, resulting in elevated levels of chloride and sulfate salts, as well as sodium and magnesium. The lacustrine deposits around Lake Chilika are also affected by salts due to the overflowing of brackish lake water in districts like Puri, Khurda, and Ganjam.
Saline soils in this coastal region are predominantly clay to clay loam in texture and exhibit a columnar structure. The pH of these soils ranges from 6.0 to 8.0, and during the summer, the conductivity can reach 10–40 dS/m. The percentage of exchangeable sodium in these soils varies from 18 to 27. While nitrogen and potassium content is relatively high, phosphorus levels are generally low to moderate. Saline soils also contain sufficient amounts of sulfate, boron, molybdenum, and chloride. Crop failure on these soils is often attributed to factors such as plasmolysis of seeds and roots during germination, seedling death, reduced absorption of essential nutrients like potassium, calcium, and magnesium due to excessive sodium, toxicity caused by boron, and injury resulting from hydrogen sulfide.
Fortunately, the risks associated with salinity are reduced during the rainy season as heavy rainfall leads to the dilution and flushing out of soluble salts. Rice is the primary kharif (monsoon season) crop in areas with consistent and evenly distributed rainfall. While kharif rice is not particularly susceptible to salinity, there can be instances of early dryness and cyclonic sea water flooding that pose risks to rice cultivation. High-yielding salt-tolerant rice cultivars such as Lunishree, SR-26B, and Mohan outperform indigenous saline-resistant varieties like Sola, Pateni, and Cuttack Chandi in these areas. Other crops such as safflower, mustard, barley, linseed, chili, sugar beet, tomato, spinach, and certain cucurbits thrive on these saline soils. Cotton can also be successfully cultivated on saline soils with appropriate management practices.
Reclaiming coastal saline soils with high exchangeable salt content but low pH can be achieved by applying lime, which replaces a portion of the exchangeable sodium or hydrogen with calcium. The application of organic manure, straw recycling, and the incorporation of green manure crops also help reduce salinity and alkalinity while improving soil structure.
Cultural practices such as cropping on alternate ridges of irrigated furrows and leaving the intermediate furrows fallow can protect crops against salinity. Preventive measures such as the construction of salt embankments, installation of adequate drainage systems, flushing out of soluble salts, construction of sluices across creeks, and the establishment of shelter belts above and near salty areas significantly reduce salinity threats in the coastal regions. By implementing these strategies and adopting appropriate agricultural practices, farmers can effectively manage and utilize saline soils for productive crop cultivation.
Brown Forest Soil
These soils, which are associated with forest areas, cover approximately 0.17 million hectares of land in the districts of Phulbani, Kandhamal, Rayagada, and parts of Ganjam and Nayagarh in Odisha. They are characterized by a range of colors from brown to grey-brown, have a light texture, and exhibit an acidic pH. These soils contain a moderate to high amount of organic matter and nitrogen, which contributes to their fertility. The levels of phosphorus and potassium are moderate, providing essential nutrients for plant growth. Additionally, these soils have a high content of most micronutrients, except for molybdenum.
Soil erosion is a significant issue in sloping terrains associated with these soils, leading to the development of barren fields. Shifting cultivation, commonly known as ‘podu cultivation,’ is a traditional practice in these areas but contributes to land degradation. Implementing land-shaping techniques and transitioning away from podu cultivation can greatly improve soil and land management, preserving the productivity of these soils.
The moisture-retaining capacity of these soils makes them suitable for cultivating certain crops. Ginger, turmeric, and tapioca thrive in these soil conditions, as they require a consistent level of moisture. Additionally, maize, wheat, and mustard are well-suited for cultivation in these soils.
Established fruit crops such as jackfruit, mango, guava, and citrus have successfully grown in these soils, taking advantage of their favorable characteristics. In areas where the soils have deteriorated, social forestry plantings have proven to be effective in rehabilitating the land and improving soil conditions.
Efforts to conserve and manage these soils, including erosion control measures, sustainable agricultural practices, and the promotion of agroforestry, can contribute to the long-term sustainability of these forest-associated soils in Odisha.
Mixed Red and Black Soil
These soils are characterized by the coexistence of red and black soils, with black soil occurring in patches within the main body of red soil. The intermixing of these two soil types creates a unique pattern where red soils are predominantly found in the upper ridges, while black soils are concentrated in the lower ridges. This distinct soil composition spans approximately 0.16 million hectares of land in the western districts of Sambalpur, Bargarh, Sonepur, and Bolangir in Odisha.
The texture of these soils ranges from light to medium, and they exhibit a neutral pH. Black soils are rich in calcium, while red soils are high in iron content, leading to the formation of a catenary structure within the soil profile. These soils also have good depth, allowing for deeper root penetration, but their fertility level is generally low. Zinc deficiency is a common issue in lowland rice soils within these areas.
With proper fertilizer application and soil management practices, a variety of crops can be successfully cultivated in these soils. Rice, sugarcane, maize, ragi (finger millet), groundnut, sesame, and various types of vegetable crops can thrive in this soil type.
However, it is important to consider that the productivity of crops in Odisha is influenced by the diverse climatic conditions, terrain variations, and parent material of the soils. The heterogeneity of soils across the region often results in lower average productivity for a range of crops.
To overcome the challenges associated with these soils and maximize crop yields, it is crucial to identify and effectively address specific soil concerns. Implementing appropriate soil management practices, such as balanced fertilization, crop rotation, soil amendments, and soil conservation measures, can significantly enhance the productivity and sustainability of agriculture in these areas of Odisha. By understanding and addressing the unique characteristics of these soils, farmers can optimize their agricultural practices and improve overall crop productivity in the region.
Soil Degradation in Odisha and Conservation Strategies
Soil degradation is a significant issue in Odisha, affecting the state’s agricultural productivity and sustainability. Several factors contribute to soil degradation in the region, including natural processes, improper land management practices, and human activities. Here are some key aspects of soil degradation in Odisha:
Major Causes of Soil Degradation
- Erosion: Soil erosion is a major form of soil degradation in Odisha. Factors such as high-intensity rainfall, hilly terrain, and improper land management practices, including deforestation and improper cultivation techniques, contribute to soil erosion. Erosion leads to the loss of topsoil, which is rich in organic matter and essential nutrients, reducing soil fertility and agricultural productivity.
- Waterlogging and Salinity: In certain areas, waterlogging and salinity pose significant challenges to soil health. Poor drainage systems, coastal intrusion of seawater, and improper irrigation practices can lead to waterlogging and the accumulation of salts in the soil. Excess salt content hampers crop growth and diminishes soil fertility, resulting in decreased agricultural yields.
- Nutrient Depletion: Continuous cultivation without proper nutrient management can deplete essential nutrients from the soil. Insufficient application of fertilizers or improper fertilizer use can lead to nutrient imbalances, affecting plant growth and reducing soil fertility over time. Nutrient depletion is a common form of soil degradation observed in many agricultural areas of Odisha.
- Soil Contamination: Soil contamination, particularly due to industrial activities, mining operations, and improper waste disposal, is a significant concern in certain parts of Odisha. Contaminants such as heavy metals, pesticides, and industrial chemicals can accumulate in the soil, posing risks to both human health and the environment. Contaminated soils may become unsuitable for agriculture and require remediation efforts.
- Overgrazing and Deforestation: Uncontrolled grazing and deforestation contribute to soil degradation in Odisha. Overgrazing can lead to soil compaction, loss of vegetation cover, and reduced organic matter content. Deforestation, especially in hilly regions, accelerates soil erosion and disrupts natural ecosystems, further exacerbating soil degradation.
Conservation Strategies
Soil degradation in Odisha is a pressing issue that requires effective conservation strategies to protect and restore soil health. Here are some key soil degradation challenges in Odisha and corresponding conservation strategies:
- Erosion Control: Soil erosion is a major concern in Odisha. Implementing soil conservation measures such as contour plowing, terracing, and the construction of bunds can help prevent erosion by reducing the speed of water runoff and encouraging water infiltration into the soil. Afforestation and reforestation efforts on hillsides and degraded lands can also stabilize the soil, reduce erosion, and enhance biodiversity.
- Water Management: Proper water management is crucial to prevent waterlogging and salinization in agricultural fields. This includes the installation of efficient drainage systems to ensure proper water flow and prevent waterlogging. Controlled irrigation practices, such as drip irrigation and sprinkler systems, can minimize excess water usage and reduce the risk of soil salinity.
- Nutrient Management: Balancing nutrient inputs and practicing efficient nutrient management is essential to prevent nutrient depletion and maintain soil fertility. Soil testing should be conducted regularly to determine nutrient deficiencies and tailor fertilizer applications accordingly. Adopting integrated nutrient management practices, including the use of organic fertilizers, crop rotation, and cover cropping, can help improve soil nutrient levels and reduce dependency on synthetic fertilizers.
- Soil Conservation Agriculture: Promoting soil conservation agriculture practices can mitigate soil degradation. Conservation tillage techniques, such as no-till or reduced tillage, help preserve soil structure, increase organic matter content, and reduce erosion. Crop residue management, including the use of crop residues as mulch or for composting, enhances soil organic matter, moisture retention, and nutrient cycling.
- Agroforestry and Integrated Farming Systems: Integrating trees, shrubs, and other perennial vegetation into agricultural systems through agroforestry practices helps combat soil degradation. Agroforestry systems provide multiple benefits, including soil erosion control, nutrient cycling, improved microclimate, and diversification of income sources for farmers.
- Awareness and Capacity Building: Enhancing awareness among farmers and stakeholders about the importance of soil conservation and sustainable land management practices is crucial. Providing training programs, workshops, and extension services can help disseminate knowledge and build the capacity of farmers to adopt soil conservation strategies effectively.
- Policy Support: Effective soil conservation requires supportive policies and incentives. Governments and relevant agencies should develop and implement policies that promote sustainable land management practices, offer financial support for soil conservation measures, and enforce regulations to prevent soil degradation from industrial and mining activities.
Conclusion
By implementing these conservation strategies and adopting sustainable land management practices, Odisha can mitigate soil degradation, protect its agricultural productivity, and ensure the long-term sustainability of its soil resources. Collaboration among farmers, researchers, policymakers, and local communities is essential to address soil degradation effectively and achieve sustainable agricultural development in the state.