Fertilizer consumption in India has increased signifi-cantly in the last three decades. Total NPK (N, P₂O₅ and K₂O) consumption increased nine-fold (from 2 million to 18 million tonnes) between 1969/1970 and 1999/2000. Per-hectare NPK consumption increased from 11 to 95 kg in the same period. After reaching a record level in 1999/2000, fertilizer consumption in India has been irregular. It has fluctuated around 17 million tonnes since 2000/01 (Table 11).

Fertilizer consumption varies widely between the AEZ owing to the substantial differences in soil type, fertility status, crop, weather, rainfall, irrigation facilities, etc. (Table 12). AEZ 4 was the most important region in terms of fertilizer use and consumed 3.5 million tonnes of fertilizer (21 percent of the total) in 2003/04 on 30 million ha of cropped area. In six AEZs (Nos. 2, 4, 6, 7, 9 and 13), the annual fertilizer consumption has exceeded one million tonnes and together they accounted for about 63 percent of total fertilizer consumption.

Per-hectare consumption was highest in AEZ 7 followed by AEZ 9 and AEZ 18. The rate of fertilizer consumption was more than 100 kg/ha in six of the AEZs (Nos. 4, 7, 8, 9, 13 and 18), which cover 38.4 percent of gross cropped area (GCA). In ten of the regions (AEZs 1, 2, 3, 5, 6, 12, 14, 15, 16 and 19), covering 49.5 percent of the area, per-hectare fertilizer consumption ranged between 50 and 100 kg, whereas in the remaining four regions (AEZs 10, 11, 17 and 20) covering 12.1 percent of the area, the rate of fertilizer consumption was less than 50 kg/ha.

All 20 AEZs of India have been grouped into six broad ecosystems on the basis of bio-climatic factors.

The arid ecosystem, comprising three eco-regions (AEZs 1 – 3), consumed 1.46 million tonnes of fertilizer (N+P₂O₅+K₂O) in 2003/04 and accounted for 8.7 percent of total fertilizer consumption. This ecosystem covers 25.1 million ha, representing 13.4 percent of the total GCA of the country. Per-hectare fertilizer consumption was 58.2 kg, varying from 54.6 kg in AEZ 2 to 76.2 kg in AEZ 3. In terms of nutrients, N, P₂O₅ and K₂O consumption was 40.1, 15.0 and 3.1 kg/ha, respectively. There was a wide variation in nutrient consumption among the AEZs of the arid ecosystem. N consumption varied from 39.5 to 55.4 kg/ha, P₂O₅ consumption from 10.2 to 20.6 kg/ha, and K₂O consumption from 1.1 to 12.7 kg/ha. Fertilizer use and crop productivity are very low in all the regions of the arid ecosystem owing to factors such as rainfed monocropping, the short length of the growing period, and erratic and scanty rainfall.

The semi-arid ecosystem is the most important ecosystem in terms of area and fertilizer use. Comprising five ecoregions (AEZs 4 – 8), it consumed 7.4 million tonnes of fertilizer (N+P₂O₅+K₂O) in 2003/04 and accounted for 47.3 percent of the total fertilizer consumption. The ecosystem covers 79.25 million ha, representing 42.4 percent of total GCA of the country. Per-hectare fertilizer consumption was 100.2 kg, varying from 65.5 kg in AEZ 6 to 177.1 kg in AEZ 7. In terms of nutrients, N, P₂O₅ and K₂O consumption was 65.6, 25.9 and 8.7 kg/ha, respectively. There was a wide variation in nutrient consumption between the AEZs of the semi-arid ecosystem. N consumption varied from 38.9 to 109.0 kg/ha, P₂O₅ consumption from 18.6 to 46.8 kg/ha, and K₂O consumption from 3.3 to 29.7 kg/ha. Although mean annual rainfall is 500 – 1 000 mm in AEZ 4, fertilizer use and crop productivity are moderately high as 65 percent of the region is under irrigated agriculture. In the northern plains, farmers have overcome the drought-prone climate by introducing tubewell irrigation. Fertilizer use and crop yields are low in AEZs 5 and 6 because rainfed farming is the traditional practice. Fertilizer use is highest in AEZ 7 because good rainfall and better irrigation facilities enable farmers to grow higher fertilizer consuming crops in this region.

The subhumid ecosystem, comprising six regions (AEZs 9 – 14), consumed 5.04 million tonnes of fertilizer (N+P₂O₅+K₂O) in 2003/04 and accounted for 30 percent of the total fertilizer consumption. The ecosystem covers 58.9 million ha, representing 31.5 percent of the total GCA of the country. Per-hectare fertilizer consumption was 85.5 kg, varying from 44.6 kg in AEZ 10 to 166.9 kg in AEZ 9. In terms of nutrients, N, P₂O₅ and K₂O consumption was 60.7, 19.0 and 5.8 kg/ha, respectively. There was a wide variation in nutrient consumption between the AEZs of the subhumid ecosystem. N consumption varied from 25.5 to 127.6 kg/ha, P₂O₅ consumption from 13.8 to 30.9 kg/ha, and K₂O consumption from 2.1 to 10.1 kg/ha. Fertilizer use and crop productivity are high in AEZ 9 because soils are deep, loamy and have developed on alluvium. Both rainfed and irrigated agriculture are practised in the region. Rice, maize, barley, pigeon pea, wheat, mustard, lentil, sugar cane and cotton are important crops. Fertilizer use is low in AEZs 10, 11 and 12 because the soils are susceptible to severe water erosion and experience partial waterlogging. Rainfed farming is practised and rice, millets, pigeon pea, green gram and black gram crops are grown. Flooding, imperfect drainage, salinity and sodicity in AEZ 13, and a severe climate, soil degradation, soil acidity and droughts in AEZ 14 are major constraints on increasing fertilizer consumption.

The humid-perhumid ecosystem comprising three regions (AEZs 15 – 17) consumed 1.01 million tonnes of fertilizer (N+P₂O₅+K₂O) in 2003/04 and accounted for 6.01 percent of total fertilizer consumption. The ecosystem covers 11.92 million ha, representing 6.37 percent of the total GCA of the country. Per-hectare fertilizer consumption was 85.0 kg, ranging from 36.4 kg in AEZ 17 to 94.7 kg in AEZ 15. In terms of nutrients, N, P₂O₅ and K₂O consumption wass 45.5, 22.0 and 17.6 kg/ha, respectively. There was a wide variation in nutrient consumption between the AEZs of the humid-perhumid ecosystem. N consumption varied from 26.8 to 49.5 kg/ha, P₂O₅ consumption from 6.3 to 24.8 kg/ha, and K₂O consumption from 3.3 to 20.3 kg/ha. Fertilizer use and crop productivity are relatively high in AEZ 15 because there are rice-based cropping systems and the length of growing period is 210 days. Fertilizer use is very low in AEZ 17 owing to adverse climate conditions and Jhum (shifting) cultivation.

The coastal ecosystem, comprising two regions (AEZs 18 and 19), consumed 1.34 million tonnes of fertilizer (N+P₂O₅+K₂O) in 2003/04 and accounted for 8.0 percent of total fertilizer consumption. The ecosystem covers 11.82 million ha, representing 6.32 percent of the total GCA of the country. Per-hectare fertilizer consumption was 113.6 kg, ranging from 80.3 kg in AEZ 19 to 144.7 kg in AEZ 18. In terms of nutrients, N, P₂O₅ and K₂O consumption was 63.7, 26.3 and 23.7 kg/ha, respectively. There was a wide variation in nutrient consumption among the AEZs of the coastal ecosystem. N consumption varied from 40.5 to 85.3 kg/ha, P₂O₅ consumption from 17.0 to 34.9 kg/ha, and K₂O consumption from 22.7 to 24.5 kg/ha. Fertilizer use and crop productivity are relatively low in AEZ 19 owing to excessive leaching, waterlogging and steep slopes.

The island ecosystem, comprising AEZ 20, consumed only 700 tonnes of fertilizer (N+P₂O₅+K₂O) in 2003/04 over an area of 50 000 ha. Per-hectare fertilizer consumption was 14.3 kg. In terms of nutrients, N, P₂O₅ and K₂O consumption was 6.7, 6.3 and 1.2 kg/ha, respectively. Fertilizer use and crop productivity are very low in AEZ 20 owing to severe soil erosion. The land use is dominated by plantation crops.

Before the 1950s, fertilizer use was very low and was confined to plantation crops. The introduction of fertilizer-responsive HYVs and expansion in the irrigated area led to a sharp increase in fertilizer application on field crops. Per-hectare fertilizer consumption is higher in the case of crops with a larger proportion of irrigated area. About 40 percent of the agricultural area in India is irrigated, accounting for 68.5 percent of total fertilizer consumption (Table 13). Six crops (rice, wheat, cotton, sugar cane, rapeseed and mustard) are estimated to account for more than two-thirds of the total fertilizer consumption in the country. The fertilizer-use pattern for major crops is discussed below.

Paddy rice is the most important crop in India in terms of both area and fertilizer use. Occupying an area of 44.7 million ha, it accounted for 31.8 percent (5.34 million tonnes) of total fertilizer consumption in 2003/04. Fertilizer use on irrigated paddy (155 kg/ha) is double that on rainfed paddy (77.6 kg/ha). The shares of irrigated and rainfed paddy in total fertilizer consumption were 22.2 and 9.6 percent, respectively. The average per-hectare use of fertilizer on paddy was 119.1 kg (81.7 kg/ha N, 24.3 kg/ha P₂O₅ and 13.1 kg/ha K₂O).

Wheat is the second most important foodgrain crop, grown on an area of 25.7 million ha. It is grown largely under irrigated conditions and accounts for 20.5 percent (3.44 million tonnes) of total fertilizer consumption. Fertilizer use per-hectare is 137 kg (100 kg/ha N, 30 kg/ha P₂O₅ and 7 kg/ha K₂O). Fertilizer use on irrigated wheat (144.9 kg/ha) is almost double that rainfed wheat (75.9 kg/ha) with the same trend for all the nutrients (N, P₂O₅ and K₂O).

Sorghum is an important cereal crop in India. Occupying an area of 9.9 million ha, it accounted for 2.9 percent (0.49 million tonnes) of total fertilizer consumption in 2003/04. Fertilizer use on irrigated sorghum (98.3 kg/ha) was more than double that on rainfed sorghum (43.6 kg/ha). The shares of irrigated and rainfed sorghum in total fertilizer consumption were 0.5 and 2.4 percent, respectively. The verage per-hectare use of fertilizer on sorghum was 47.5 kg (29.2 kg/ha N, 14.2 kg/ha P₂O₅ and 4.1 kg/ha K₂O).

Pearl millet is another important cereal crop in India. It occupied an area of 9.8 million ha and accounted for 1.7 percent (0.29 million tonnes) of total fertilizer consumption in 2003/04. Fertilizer use on irrigated pearl millet (79.5 kg/ha) was more than three-fold that of rainfed pearl millet (23.8 kg/ha). The shares of irrigated and rainfed pearl millet in total fertilizer consumption were 0.4 and 1.3 percent, respectively. The average per-hectare use of fertilizer on pearl millet is 28.2 kg (21.9 kg/ha N, 5.5 kg/ha P₂O₅ and 0.8 kg/ha K₂O).

Occupying 3.5 percent of GCA, maize accounts for 2.3 percent of total fertilizer consumption. Maize is grown mostly under rainfed conditions. Per-hectare fertilizer use is 60.2 kg, which consists of 41.7 kg/ha N, 14.7 kg/ha P₂O₅ and 3.8 kg/ha K₂O. The rate of fertilizer use on irrigated maize is 92 kg/ha compared with 51 kg/ha on rainfed maize. On rainfed maize, N, P₂O₅ and K₂O use is 36.6, 11.0 and 3.6 kg/ha, respectively, and 59.6, 27.7 and 4.8 kg/ha, respectively, on irrigated maize.

Pigeon pea is one of the major pulse crops in India. It accounted for 0.8 percent (0.13 million tonnes) of total fertilizer consumption on an area of 3.7 million ha in 2003/04. Fertilizer use on irrigated pigeon pea (60.0 kg/ha) was nearly double that on rainfed pigeon pea (34.2 kg/ha). The shares of irrigated and rainfed pigeon pea in total fertilizer consumption were 0.1 and 0.7 percent, respectively. The average per-hectare use of fertilizer on pigeon pea was 36.2 kg (20.9 kg/ha N, 13.3 kg/ha P₂O₅ and 2.0 kg/ha K₂O).

Rapeseed and mustard are the major oilseed crops of India. They occupied an area of 6.0 million ha and accounted for 3.4 percent (0.57 million tonnes) of total fertilizer consumption in 2003/04. Fertilizer use on irrigated rapeseed and mustard (116.5 kg/ha) was almost double that on rainfed rapeseed and mustard (61.3 kg/ha). The shares of irrigated and rainfed rapeseed and mustard in total fertilizer consumption were 2.6 and 0.8 percent, respectively. The average per-hectare use of fertilizer on rapeseed and mustard is 97.0 kg (69.1 kg/ha N, 25.0 kg/ha P₂O₅ and 2.9 kg/ha K₂O).

Groundnut is the most important oilseed crop of India after rapeseed and mustard. Occupying an area of 6.6 million ha, it accounted for 2.9 percent (0.49 million tonnes) of total fertilizer consumption in 2003/04. The major groundnut-growing states are Gujarat and Karnataka. Fertilizer use on irrigated groundnut (118.0 kg/ha) was higher than on rainfed groundnut (67.2 kg/ha). The shares of irrigated and rainfed groundnut in total fertilizer consumption were 0.8 and 2.1 percent, respectively. The average per-hectare use of fertilizer on groundnut was 76.6 kg (24.4 kg/ha N, 39.3 kg/ha P₂O₅ and 12.9 kg/ha K₂O).

Sugar cane is the major sugar crop of India. Being a long-duration crop, its nutritional requirements are high. In 2003/04, it occupied an area of 4.3 million ha and accounted for 5.4 percent (0.91 million tonnes) of fertilizer consumption. The major sugar-cane-growing states are Uttar Pradesh, Tamil Nadu, and Maharashtra. Fertilizer use on irrigated sugar cane was 212.0 kg/ha compared with 150.4 kg/ha on rainfed sugar cane. The shares of irrigated and rainfed sugar cane in total fertilizer consumption were 5.3 and 0.1 percent, respectively. The average per-hectare use of fertilizer on sugar cane was 207.1 kg (124.8 kg/ha N, 44.0 kg/ha P₂O₅ and 38.3 kg/ha K₂O).

Cotton is the major fibre crop of India. In 2003/04, it occupied an area of 8.5 million ha and accounted for 6.0 percent (1.01 million tonnes) of total fertilizer consumption. Fertilizer use on irrigated cotton (153.5 kg/ha) was higher than on rainfed cotton (97.7 kg/ha). The shares of irrigated and rainfed cotton in total fertilizer consumption were 2.7 and 3.3 percent, respectively. The average per-hectare use of fertilizer on cotton was 116.8 kg (89.5 kg/ha N, 22.6 kg/ha P₂O₅ and 4.8 kg/ha K₂O).

After cotton, jute is the next most important fibre crop. Occupying an area of 0.8 million ha, it accounted for 0.2 percent (0.03 million tonnes) of total fertilizer consumption in 2003/04. Fertilizer use on irrigated jute (88.6 kg/ha) was more than double that on rainfed jute (37.1 kg/ha). The share of irrigated and rainfed jute in total fertilizer consumption was 0.1 percent. The average per-hectare use of fertilizer on jute was 54.4 kg (38.0 kg/ha N, 11.5 kg/ha P₂O₅ and 5.0 kg/ha K₂O).

Crops other than those mentioned above occupied an area of 60.4 million ha and accounted for 22.1 percent (3.71 million tonnes) of total fertilizer consumption in 2003/04. Per-hectare fertilizer use on irrigated crops (182.9 kg/ha) was more than six times that on rainfed crops (29.2 kg/ha). The shares of irrigated and rainfed crops in total fertilizer consumption were 13.7 and 8.4 percent, respectively. The average per-hectare use of fertilizer on other crops was 61.3 kg (34.5 kg/ha N, 18.5 kg/ha P₂O₅ and 8.4 kg/ha K₂O).

Rice-wheat is the most important cropping system in terms of area, fertilizer use and crop productivity. It is practised in various environments and on different soil types and covers an estimated area of about 10 million ha on the IGP. Per-hectare fertilizer use under the rice-wheat cropping system in the IGP is estimated at 334 kg. It varies from 258 kg in the Lower Gangetic Plain (LGP) region to 444 kg in the Trans-Gangetic Plain (TGP) (Haryana) region (Table 14). In the IGP, farmers apply 117.3 kg/ha N, 35.2 kg/ha P₂O₅ and 11.8 kg/ha K₂O on rice and 120.3 kg/ha N, 38.2 kg/ha P₂O₅ and 11.1 kg/ha K₂O on wheat. The productivity of rice and wheat crops in the IGP is estimated to be 2.95 and 3.95 tonnes/ha, respectively. In the IGP, the productivity of rice-wheat cropping systems decreases from west to east.