Introduction
India is a country of more than 1 250 million people. It is the seventh largest nation in the world with a geographical area of 328.7 million ha. Agriculture is the mainstay of the Indian economy, contributing about 22 percent of gross domestic product (GDP) and providing a livelihood to two-thirds of the population. The net cultivated area has been about 141 million ha for the last 30 years. However, there has been a progressive increase in the gross cropped area as the cropping intensity has increased from 118 to 135 percent in the last three decades. The total gross cropped area is about 190 million ha. There are 115.6 million farmholdings, with an average size of 1.41/ha.
The country has a diverse landscape and a climate varying from the areas with highest rainfall such as Mawsynram near Cherrapunji (Meghalaya) to the driest parts of western Rajasthan with negligible rain and from a hot and humid southern peninsula to the snowbound Himalayan Mountains. Broadly, the climate of India is of the tropical monsoon type. It has four seasons: winter (January–February), a hot summer (March–May), rainy southwest monsoon (June–September), and post-monsoon (October–December). The climate is affected by two seasonal winds: the southwest monsoon and the northeast monsoon. The distribution of rainfall is very uneven in terms of time and space (Table 1). About 72 percent of the area receives an annual rainfall of no more than 1 150 mm.
India has a net irrigated area (land area that receives irrigation from the different sources) of 54.68 million ha and a gross irrigated area (total area of crops that are irrigated) of 75.14 million ha (the largest in the world). Surface water and groundwater resources contribute 46 and 54 percent, respectively, of the total. Food crops occupy 69 percent of the irrigated area, the remaining 31 percent being under non-food crops.
| Category | Rainfall (mm) | Area (%) |
| Dry | 0–750 | 30 |
| Medium | 750–1 50 | 42 |
| 1 150–2 000 | 20 | |
| Assured | > 2 000 | 8 |
The land in India suffers from varying degrees of degradation. Soil fertility depletion is a cause of concern for Indian agriculture. There exists a gap of about 10 million tonnes of nutrients (NPK) between the removal of nutrients by crops and their addition through fertilizers. The use of plant nutrients per hectare is relatively low and imbalanced, and this is one of the major reasons for low crop yields in India.
There are two main cropping seasons, namely kharif (April–September) and rabi (October–March). The major kharif crops include rice, sorghum, pearl millet, maize, cotton, sugar cane, soybean and groundnut, and the rabi crops are wheat, barley, gram, linseed, rapeseed and mustard. With its good range of climates and soils, India has a good potential for growing a wide range of horticultural crops such as fruits, vegetables, potato, tropical tuber crops, mushrooms, ornamental crops, medicinal and aromatic crops, spices and plantation crops. Foodgrain (cereals and pulses) crops dominate the cropping pattern and account for about 60 percent of total gross cropped area (Figure 1).
AGRO-ECOLOGICAL ZONES
Agriculture is highly dependent on soils and climate. The ever-increasing need for food to support the growing population in the country demands a systematic appraisal of its soil and climate resources in order to prepare effective land-use plans. India has a variety of landscapes and climate conditions and this is reflected in the development of different soils and types of vegetation. Based on 50 years of climate data and an up-to-date soil database, the country has been divided into 20 agro-ecological zones (AEZs), as shown in Figure 2.
Source: Sehgal et. al., 1992.
Each AEZ is as uniform as possible in terms of physiography, climate, length of growing period and soil type for macrolevel land-use planning and effective transfer of technology. Table 2 gives a brief description of important features of the AEZs.
MAJOR SOIL GROUPS
The great diversity in landforms, geological formations and climate conditions in India has resulted in a large variety of soils (Figure 3). Apart from a few soil orders (Andisols and Spodosols), all the major soils of the world are represented in India. Broadly, Indian soils consist of eight major groups, of which four are of agricultural importance: alluvial soils, black soils, red soils and lateritic soils. The four other broad soil groups that occur fairly extensively in India are: saline and sodic soils, desert soils, forest and hill soils, and peaty and marshy soils. These soil groups are related closely to the geographical character and the climate of the regions in which they occur.
Alluvial soils (Fluvisols)
Alluvial soils constitute the largest and most important soil group of India and contribute most to the agricultural wealth of the country. The soils are derived from the deposition of silt by the numerous river systems. They cover about 75 million ha in the Indo-Gangetic Plains (IGP) and Brahmaputra Valley and are distributed in the states of Punjab, Haryana, Uttaranchal, Uttar Pradesh, Bihar, West Bengal, Assam and the coastal regions of India. These soils are deficient in nitrogen (N), phosphorus and organic matter. Generally, alluvial soils range from near neutral to slightly alkaline in reaction. A wide variety of crops is grown in these soils.
Black soils (Vertisols)
Black soils are very dark and have a very high clay content. They have a high moisture retention capacity. They become extremely hard on drying and sticky on wetting. Hence, they are very difficult to cultivate and manage. These soils cover an area of about 74 million ha, mainly in the central, western and southern states of India. They are inherently very fertile. Under rainfed conditions, they are used for growing cotton, millets, soybean, sorghum, pigeon pea, etc. Under irrigated conditions, they can be used for a variety of other crops, such as sugar cane, wheat, tobacco and citrus crops.
| AEZ No. | Agro-ecological region | Geographical area (million ha) | Gross cropped area (million ha) | Physiography | Precipitation (mm) | PET (mm) | Length of growing period (days) | Major crops |
| 1. | Cold arid ecoregion with shallow skeletal soils | 15.2 (4.7%) | 0.07 | Western Himalayas | < 150 | <800 | < 90 | Vegetables, millets, wheat, fodder, barley, pulses |
| 2. | Hot arid ecoregion with desert and saline soils | 31.9 (9.7%) | 20.85 | Western Plain & Kachchha Peninsula | < 300 | 1 500–2 000 | < 90 | Millets, fodder, pulses |
| 3. | Hot arid ecoregion with red and black soils | 4.9 (1.9%) | 4.18 | Deccan Plateau | 400–500 | 1 800–1 900 | < 90 | Sorghum, safflower, cotton, groundnut, sunflower, sugar cane |
| 4. | Hot semi-arid ecoregion with alluvium-derived soils | 32.2 (9.8%) | 30.05 | Northern Plain & Central Highlands including parts of Gujarat Plains | 500–800 | 1 400–1 900 | 90–150 | Millets, wheat, pulses, maize; irrigated cotton & sugar cane |
| 5. | Hot semi-arid ecoregion with medium and deep black soils | 17.6 (5.4%) | 11.04 | Central (Malwa) Highlands,Gujarat Plains & Kathiawar Peninsula | 500–1 000 | 1 600–2 000 | 90–150 | Millets, wheat, pulses |
| 6. | Hot semi-arid ecoregion with shallow and medium (dominant) black soils | 31.0 (9.5%) | 25.02 | Deccan Plateau | 600–1000 | 1 600–1 800 | 90–150 | Millets, cotton, pulses, sugar cane under irrigation |
| 7. | Hot semi-arid ecoregion with red and black soils | 16.5 (5.2%) | 6.19 | Deccan (Telangana) Plateau & Eastern Ghats | 600–1 000 | 1 600–1 700 | 90–150 | Millets, oilseeds, rice, cotton & sugar cane under irrigation |
| 8. | Hot semi-arid ecoregion with red loamy soils | 19.1 (5.8%) | 6.96 | Eastern Ghats (Tamil Nadu uplands) & Deccan Plateau (Karnataka) | 600–1 000 | 1 300–1 600 | 90–150 | Millets, pulses, oilseeds (groundnut), sugar cane & rice under irrigation |
| 9. | Hot subhumid (dry) ecoregion with alluvium-derived soils | 12.1 (3.7%) | 11.62 | Northern Plain | 1 000–1 200 | 1 400–1 800 | 150–180 | Rice, wheat, pigeon pea, sugar cane, mustard, maize |
| 10. | Hot subhumid ecoregion with red and black soils | 22.3 (5.8%) | 14.55 | Central Highlands (Malwa & Bundelkhand) | 1 000–1 500 | 1 300–1 500 | 150–180 | Rice, wheat, sorghum, soybean, gram, pigeon pea |
| 11. | Hot subhumid ecoregion with red and yellow soils | 11.1 (4.3%) | 6.47 | Eastern Plateau (Chhattisgarh Region) | 1 200–1 600 | 1 400–1 500 | 150–180 | Rice, millets, wheat, pigeon pea, green gram, black gram |
| 12. | Hot subhumid ecoregion with red and lateritic soils | 26.8 (8.2%) | 12.09 | Eastern (Chhota Nagpur) Plateau and Eastern Ghats | 1 000–1 600 | 1 400–1 700 | 150–180 | Rice, pulses, millets |
| 13. | Hot subhumid (moist) ecoregion with alluvium-derived soils | 11.1 (3.4%) | 10.95 | Eastern Plains | 1 400–1 600 | 1 300–1 500 | 180–210 | Rice, wheat, sugar cane |
| 14. | Warm subhumid to humid with inclusion of perhumid ecoregion with brown forest and podzolic soils | 18.2 (5.6%) | 3.20 | Western Himalayas | 1 600–2 000 | 800–1 300 | 180–210 | Wheat, millets, maize, rice |
| 15. | Hot subhumid (moist) to humid (inclusion of perhumid) ecoregions with alluvial-derived soils | 12.1 3.7%) | 8.99 | Bengal Basin and Assam Plain | 1 400–2 000 | 1 000–1 400 | > 210 | Rice, jute, plantation crops |
| 16. | Warm perhumid ecoregion with brown and red hill soils | 9.6 (2.9%) | 1.37 | Eastern Himalayas | 2 000–4 000 | <1 000 | > 210 | Rice, millets, potato, maize, sesame, Jhum* cultivation is common |
| 17. | Warm perhumid ecoregion with red and lateritic soils | 10.6 (3.3%) | 1.56 | North-Eastern Hills | 1 600–2 600 | 1 000–1 100 | > 210 | Rice, millets, potato, plantation crops, Jhum* cultivation is common |
| 18. | Hot subhumid to semi-arid ecoregion with coastal alluvium-derived soils | 8.5 (2.6%) | 6.12 | Eastern Coastal Plains | 900–1 600 | 1 200–1900 | 90>210 | Rice, coconut, black gram, lentil, sunflower, groundnut |
| 19. | Hot humid perhumid ecoregion with red, lateritic and alluvium-derived soils | 11.1 (3.6%) | 5.70 | Western Ghats and Coastal Plains | 2 000–3 200 | 1 400–1 600 | > 210 | Rice, tapioca, coconut, spices |
| 20. | Hot humid / perhumid island ecoregion with red loamy and sandy soils | 0.8 (0.3%) | 0.05 | Islands of Andaman & Nicobar and Lakshadweep | 1 600–3 000 | 1 400–1 600 | > 210 | Rice, coconut, areca nut, oil palm |
Source: Sehgal et al., 1992.
Source: DSMW-FAO-UNESCO
Original scale: 1.5 million
Red soils (Acrisols)
Ancient crystalline and metamorphic rocks have given rise to red soils. These soils are found predominantly in the states of Andhra Pradesh, Tamil Nadu, Karnataka, Maharashtra, Orissa, Goa and in the northeastern states. They have limitations of soil depth, poor water and nutrient-holding capacity, excessive drainage, runoff and are generally poor in N, P, zinc (Zn), sulphur (S) and humus. Under good management, these soils can be used profitably for a variety of crops such as millets, rice, groundnut, maize, soybean, pigeon pea, green gram, jute, tea, cashew, cocoa, grapes, banana, papaya and mango.
Laterite and lateritic soils (Ferralsols and Dystric Nitisols)
Laterite and lateritic soils are deeply weathered soils with a high clay content, having low base and silica owing to pronounced leaching. They are generally found in Kerala, Tamil Nadu, Karnataka, Andhra Pradesh and the northeastern region, and occupy about 25 million ha. The major limitations posed by these soils include deficiency of P, potassium (K), calcium (Ca), Zn and boron (B), high acidity and toxicity of aluminum (Al) and manganese (Ma). The important crops grown on these soils are rice, banana, coconut, areca nut, cocoa, cashew, coffee, tea and rubber.
Desert (arid) soils (Arenosols, Calcisols and Gypsisols)
Desert soils constitute the soils with negligible vegetation in both hot and cold regimes. They cover an area of about 29 million ha. The sandy material results in poor profile development under arid conditions. Water deficiency is the major constraint in cultivating these soils. A gypsic horizon is common in extremely arid areas such as Bikaner and Jaisalmer in Rajasthan. These soils are very prone to wind erosion.
Forest and hill soils (Cambisols and Luvisols)
Forest and hill soils are found at high as well as low elevations where rainfall is sufficiently high to support forest growth. Soil formation is governed mainly by the deposition of organic matter derived from the forest growth. Brown forest and Podzolic soils are common in the Northern Himalayas, while the Deccan Plateau forests have red and lateritic soils.
Saline and sodic soils (Solonchaks and Solonetz)
Saline and sodic soils occur under semi-arid conditions and occupy an area of 10 million ha. They are widely distributed in Rajasthan, Punjab, Haryana, Uttar Pradesh, Madhya Pradesh, Maharashtra and Gujarat. The sodic soils pose serious problems of a high sodium (Na) content, poor physical conditions and nutrient deficiency. Despite many limitations, once ameliorated using gypsum, sodic soils are used successfully for growing rice followed by wheat.
Peaty and marshy soils (Histosols)
Peaty and marshy soils are formed by plants growing in the humid regions under permanently waterlogged conditions. They are found in Kerala, Orissa, West Bengal (Sundarbans) and along the South-East coast of Tamil Nadu. Where properly drained and fertilized, these soils often produce a very good rice crop.
SOIL FERTILITY STATUS
Being a tropical country, the organic carbon (C) content of the Indian soils is very low. The deficiency of N is universal in India. Most of the Indian soils are low to medium in P. Over time, K deficiency has also become widespread. The deficiency of S is increasing (Table 3). Besides primary and secondary nutrients, the increasing deficiency of micronutrients is becoming a cause of concern. Among the micronutrients, the deficiency of Zn is the most acute, followed by B (Table 4).
| Nutrient | No. of samples analysed | Percent are of samples by category | ||
| Low | Medium | High | ||
| N | 3 650 004 | 63 | 26 | 11 |
| P | 3 650 004 | 42 | 38 | 20 |
| K | 3 650 004 | 13 | 37 | 50 |
| S | 27 000 | 40 | 35 | 25 |
Source: Motsara, 2002.
In general, the deficiency of at least five nutrients (N, P, K, S & Zn) has become fairly widespread. There is a need to promote the use of types of fertilizers required to correct the deficiency of all these nutrients. To improve the naturally low organic matter content of the soil, the application of sufficient quantities of organic manures is essential.
| Nutrient | No. of samples analysed | % of deficient samples |
| Zn | 251 660 | 49 |
| Fe | 251 660 | 12 |
| Mn | 251 660 | 5 |
| Cu | 251 660 | 3 |
| B | 36 825 | 33 |
| Mo | 36 825 | 13 |
Source: Singh, 2001.
FARM SIZES
Indian agriculture is characterized by the small size of farmholding and the size is decreasing continuously. There are about 115.6 million holdings in India with an average size of 1.4 ha (Table 5). The size of farmholdings in India fell from 2.3 ha in 1970/71 to 1.47 ha in 1995/96. About 62 percent of the farmholdings are less than 1 ha, covering only 17.2 percent of the agricultural land. The large holdings (10 ha and more) constitute only 1.2 percent of the total number but cover about 14.8 percent of the total cultivated area. The holdings are also fragmented. This is a serious impediment to the mechanization of Indian agriculture.
| Category of holding | Number (million) | Area (million ha) | Average size (ha) | |||
| 1970/71 | 1995/96 | 1970/71 | 1995/96 | 1970/71 | 1995/96 | |
| Marginal | 35.7 | 71.2 | 14.5 | 28.1 | 0.41 | 0.40 |
| (< 1 ha) | (50.6) | (61.6) | (9.0) | (17.2) | ||
| Small | 13.4 | 21.6 | 19.3 | 30.7 | 1.44 | 1.42 |
| (1 – 2 ha) | (19.1) | (18.7) | (11.9) | (18.8) | ||
| Semi-medium | 10.7 | 14.3 | 30.0 | 39.0 | 2.81 | 2.73 |
| (2 – 4 ha) | (15.2) | (12.3) | (18.5) | (23.8) | ||
| Medium | 7.9 | 7.1 | 48.2 | 41.4 | 6.08 | 5.84 |
| (4 – 10 ha) | (11.3) | (6.1) | (29.8) | (25.3) | ||
| Large | 2.8 | 1.4 | 50.1 | 24.2 | 18.10 | 17.21 |
| (> 10 ha) | (3.9) | (1.2) | (30.9) | (14.8) | ||
| Total | 70.5 | 115.6 | 162.1 | 163.4 | 2.30 | 1.41 |
Source: Fertilizer Association of India, 2003/04.
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