Reaping gains: Role of phosphorous and potash in Indian agriculture

Phosphorous helps in root development, flowering, seed formation, photosynthesis and disease resistance, while potash provides plant resistance from disease and stress

Phosphorous (P) is an important constituent of the human body. Calcium phosphate constitutes a major part of human skeletal bones and teeth. Therefore, it is essential that there is sufficient intake of calcium and phosphorous for healthy bones. It is only possible if food crops have enough content of these minerals.

 

Soils enriched with phosphorous can provide good quality produce, hence the importance of phosphorous in agriculture. Phosphorous helps in root development, flowering, seed formation, photosynthesis and disease resistance.

 

It also helps in absorption of nutrient nitrogen. More than half of Indian soils have medium or high deficiency of P. There is need to improve the P status of soils having medium and high deficiency of P. Potassium or potash (K) is the third primary nutrient other than nitrogen (N) and phosphorous. It plays an important role in yield and quality of crops. It helps in development of roots and stems and increases the efficiency of water and nutrients. It provides plant resistance from disease and stress, including drought, high temperature and salinity. Thus, application of potash assumes more significance in face of climate change. On the quality front, potash increases sugar, starch and protein content of the crops.

 

 

Phosphate application

 

Phosphorous is applied through fertilizer products like ammonium phosphate, single super phosphate and triple phosphate. Phosphate not taken up by the plant gets fixed in soil as dicalcium or tricalcium phosphate. This part of P is available to the plants even for subsequent crops but very slowly. Acidic soils bring this residue phosphate into solution and make available to the plants more readily. Available P also depends on concentration of P content in the soil. Therefore, it is essential that phosphorous content of the soil remains sufficiently charged.  ALSO READ | Will a poor monsoon have the same effect in 2025 as it did earlier?

 

All India average consumption of P was 38Kg per hectare in 2023-24. It was the highest in southern states at 48.5 kg/ha and the lowest in the western region at 31.4 kg/ha. Amongst the major states, P consumption was the highest in Andhra Pradesh. Other important states like Haryana, Punjab and Uttar Pradesh in north, West Bengal in East and Tamil Nadu in south had P consumption in the range of 43-47 Kg/ha in 2023-24.

 

There has been healthy growth in consumption of P from about 33,000 tonnes before the green revolution in 1967-68 to 8.3 million tonnes last year. However, given the low base, growth should have been higher for balanced fertilization.

 

The bench mark use ratio of N:P should be 2. But it has generally been higher at 3:1 over the years till the year 2008-9. It required long time extension work to improve the ratio in favour of P. A most favourable ratio of 2.1:1 was achieved in 2009-10.

 

Potash application

 

Potassium is the most neglected nutrient which is reflected in consumption patterns. Consumption of nitrogen grew from 15.6 million tonnes in 2009-10 to 20.5 million tonnes in 2023-24, a growth of 31 per cent. Consumption of potash declined by 48 per cent from 3.6 to 1.9 million tonnes during the same period. Data for average consumption of nutrients per hectare of gross cropped area shows that potash consumption almost halved from 17.7 kg/ha in 2009-10 to 8.6 kg/ha in 2023-24. But there was an increase of about 12 per cent in N consumption during the same period.

 

Fertiliser pricing and subsidy policies

 

There was a major policy change in 2010 when nutrient based subsidy (NBS) scheme was introduced. The scheme rationalised the subsidy and hence retail prices of different fertiliser products based on their content of nitrogen, phosphorous, potash and sulphur. Under the scheme, there is a fixed subsidy on each nutrient and retail prices were decontrolled. The fixed subsidy was announced initially for the year, but was switched to twice a year for each crop season due to volatility of prices of fertilizer raw materials and finished products in international markets. But a major exception was made in this policy. Urea accounting for about 80 per cent of nitrogen consumption was kept out of the NBS scheme. Its retail price continued to be controlled and remained almost frozen till now. The fixed subsidy on P and K fertilisers was gradually lowered, resulting in higher retail prices of these products.

 

In early 1990s, retail price of DAP- a flagship product in P&K category- used to be twice that of urea on Kg to Kg basis. Decontrol of P&K fertilisers distorted this ratio substantially. Controls were restored, but subsidy on these products was fixed on ad hoc basis. It was called an ad hoc concession scheme. It was hoped that introduction of NBS in 2010 will correct the inter product price distortion, but exclusion of urea made it lose opportunity. The fixed subsidy on N, P and K under NBS went through several increases and decreases depending on the international prices. Over a period of 15 years since introduction of NBS, subsidy on nitrogen has increased by almost 100 per cent, but subsidy on phosphate has gone up by only 20 per cent and subsidy on K has been reduced drastically by nearly 90 per cent. Based on international prices, the cost of DAP should not be more than double based on international prices of these most traded commodities. But the retail price DAP is more than five times that of urea for the Indian farmers.  ALSO READ | Govt to include farmers not part of PM Kisan Samman Nidhi yet: Shivraj

 

Similarly, a bag of Muriate of Potash (MOP) should cost about the same as urea, but it costs six times more than urea. With static retail price of urea for decades, farmers are paying only 15-20 per cent of its cost of production or imports. With the result nutrient use ratios have been distorted in favour of nitrogen through excess use of urea. The balanced use of N, P and K, achieved after decades, was disturbed again. N:P use ratio has been 2.5:1 for the last several years or even close to 3:1 in some years. N:P use ratio is even more distorted in northern states like it is 4.2:1 in Punjab, 3.7:1 in Haryana and 3.1:1 in Uttar Pradesh.

 

Such distortion in the use pattern of primary nutrients and lack of use of sufficient quantities of micronutrients and organic manure are resulting in sub-optimal yields of crops.

 

Comparison with other countries

 

There was 86 kg/ha consumption of P in China in 2022 compared to 36 kg /ha in India during the same period. China also had an average consumption of 70 kg of K, compared to India’s consumption of 10 kg/ha. Brazil had P consumption of 92 kg of P and K consumption of 112 kg /ha. The average yield of cereal crops was 6,380 kg/ha in China and 4,901 kg/ha in Brazil in 2022. Compared to this, India had a low yield of 3,567 kg /ha during the same period. Thus imbalanced use of primary nutrients is giving poor crop yields. This is also affecting farmers’ income.

 

Way Forward

 

A large number of soil health cards (SHC) have been issued since introduction of the scheme. At country level, nearly 50 per cent soils are low and another 50 per cent are medium in phosphorous. More than 90 per cent of soils have medium level of potash. There are variations in soil fertility status from district to district and block to block throughout the country. Farmers should follow the recommendations of SHC for application of different fertilizer products. However, distortion in retail prices of urea vis-a-vis other fertilisers has created a barrier in application of the right proportion of nutrients.

 

Instrument of subsidy on fertilisers should be used to promote balanced use of P primary nutrients in conjunction with adequate use of micronutrients and organic manure. Therefore, there is a need for policy correction to rationalise subsidy amounts on different products. Nutrient subsidy scheme should include urea to make the retail price of three primary nutrients truly product neutral.

 

Simultaneously, there is a need to increase support to micronutrients fertilisers and organic manure. Earlier it is done, the better it would be for soil health, crop productivity, farmers’ income and last but not the least for the environment.

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The writer is a visiting professor at ICRIER 

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