Understanding the role of chemical fertilizers
Foodgrains production rose from 52 to 244.8 million tonnes from 1951 to 2011 – while at the same time its share in gross domestic product (GDP) has fallen from 16 per cent in 2004-05 to 13.3 per cent in 2008-09, (Agriculture Statistics at a Glance 2011, Ministry of Agriculture) given its lower growth rate relative to industry and services – a phenomena well documented world over. What is alarming however is that the agricultural sector has been, quite often, falling short of the Plan targets. From 1960 to 2011, foodgrains production grew at a compounded annual growth rate (CAGR) of around 2 per cent. In fact, the Ninth and Tenth Five Year Plans witnessed agricultural sectoral growth rate of 2.44 per cent and 2.30 per cent respectively compared to 4.72 per cent during Eighth Five Year Plan. During the current Five Year plan, agricultural growth is estimated at 3.28 per cent against a target of 4 per cent. The Approach Paper to the Twelfth Five Year Plan emphasises the need to “redouble our efforts to ensure that 4 per cent average growth” during the Plan if not more. (Economic Survey 2011-12).
Agricultural productivity is dependent upon various factors like soil properties, climate, irrigation facilities, seed quality and variety, cropping pattern, techniques of farming, prevention from pests etc, but more importantly usage of optimum primary, secondary and micro nutrients. The ratio of important elements in a chemical fertilizers is referred to as NPK, where N is nitrogen – responsible for strong stem and foliage growth; P is phosphorus – aiding healthy root growth and flower and seed production; and, K stands for potassium – improving overall health and enhancing disease resistance. Chemical fertilizers thus have played a key role in making countries self-reliant in foodgrain production, as to a large extent it has been able to fill the nutrient gap. Global production of fertilizers stood at around 170 MT in 2009 (Table 1). The Indian Government has been pursuing policies conducive to increased availability and consumption of fertilisers at affordable prices. The annual consumption of chemical fertilizers thus, in nutrient terms (NPK), has increased from 0.07 to more than 28 MT from 1951 to 2011 and per hectare consumption (Table. 2), has increased from less than 1 kg in 1951-52 to about 144.1 kg in 2010-11. (Report of the working group on chemical fertilizer industry for the 12th Plan, Ministry of Chemicals & Fertilizers).
- Rank of India in world production (of N+P) was 3rd next to China and USA during 2009.
- Rank of India in world consumption (of NPK) was 2nd next to China during 2009.
- Consumption of total nutrients (NPK) per hectare of arable land and land under permanent crops in the world was 106.9 kg in 2009.
- The per hectare use of fertiliser was less than 1 kg in 1950-51 and has gone up to 95.6 kg in 2000-01 and further to 144.1 kg during 2010-11
- Imports are mainly from Commonwealth of Independent States, Israel, China, Iran, Dubai, South Africa and Thailand.
- India also exports urea, SSP, NPK, and MOP, K2O
to various countries such as Nepal, Bangladesh
Source: Fertiliser Statistics, 2010-11, FAI
Chemical fertilisers however, are increasingly becoming a cause of concern for scientists as well as environmentalists. Excessive use of NPK reduces the water and nutrient retention capacity of the soil, and could result in an increase in the insoluble nutrients in the soil causing pollution through leaching and contamination of ground water; and eutrophication. Despite programmes and field demonstrations by government personnel, judicious use of chemical fertilisers, supplemented with traditional manures such as vermicompost, rural or urban compost and green manure, is still a far cry. Devising integrated plant nutrient management systems, which encompass the use of bio-fertilisers, micronutrients, organic manure, chemical fertilisers needs a fillip to regain soil health, aid quality control and enhance the yield of the produce.
Fig 1. The States of Punjab (236), Andhra Pradesh, Haryana and Tamil Nadu ranked the highest in kg per hectare consumption of fertilisers in 2009-10. Moreover, according to the FAI, provisional data of 2010-11 indicates a 12.7 per cent increase in total fertiliser consumption over the previous year in the western region of India, as compared to the other regions that have shown an average increase of 3.5 per cent only.
Industry thus needs to focus on research and development for cost-effective package of fertilisers, which can survive in the eventual, fully decontrolled regime. Unconventional resources such as coal bed methane, natural gas hydrates and underground coal gasification for nitrogen fertilisers, low quality rock phosphates for phosphate fertilisers and alternate potash sources such as glauconite sands, salt water bittern, sea weeds etc. need to be researched upon with a view to reduce dependency on imports and attaining self-sufficiency in the real sense of the term.