Nitrogen emissions are soon becoming a formidable threat. Apart from agriculture, human activities are a major contributor to these emissions. The Government should soon draw up an action plan to control nitrogen pollution
Increased use of nitrogen-based manures and fertilisers in agriculture and other human activities is causing nitrogen emissions to reach uncontrolled levels. Besides posing a serious risk to human health, it is damaging the environment too. Natural sources of nitrogen emissions emanate from soils under natural vegetation and the oceans. These sources constitute about 62 per cent of the total emissions. But, according to a United Nations Environment Programme report, human-induced nitrogen emissions are beginning to surpass the natural emissions.
While nitrogen emissions from agriculture have increased alarmingly in the recent past, the combination of industrial and fossil fuel combustions are now responsible for about 10 per cent of human emissions, which equals to 7,00,000 tonnes of nitrous oxide annually.
In addition to this, atmospheric deposition is becoming another substantial human source of nitrous oxide emissions. Nitrogen compounds are released in the air, all thanks to the human activities that pollute the air and provide the ecosystems with an extra source of available nitrogen that stimulates the nitrifying and de-nitrifying microbus resulting in increased emissions.
In fact, the role of humans has resulted in the addition of large quantities of reactive nitrogen compounds to the environment, virtually doubling the natural sources of nitrous emissions that used to exist at the beginning of the industrial age. Before the industrial revolution, atmospheric concentration of nitrous oxide was maintained at a safe range by natural sinks. But due to human activities, nitrous oxide emissions have increased by about 40 per cent to 50 per cent over pre-industrial levels.
Agriculture has emerged as one of the main contributors towards nitrous emissions due to the increasing usage of nitrogen-based manures and fertilisers. According to estimates, agriculture creates 4.5 million tonnes of nitrous oxide annually, and synthetic fertilisers constitute a major source of nitrous oxide emissions.
Synthetic fertilisers cause a heavy strain on the environment as well as on the quality of the food produced. These synthetic chemicals are absorbed by the plants, which in turn are absorbed by humans. In the US, nitrous oxide emissions account for nearly 60 per cent of the total emissions from the agricultural sector. The large increase in the use of nitrogen fertilizer for the production of high nitrogen consuming crops like corn has increased the emissions of nitrous oxide.
Nitrogen emissions have also increased due to inefficient storage and handling of livestock manure, which is another direct source of agricultural nitrous oxide emissions. The absence of efficient animal waste management system in India is resulting in the creation of conditions that are favourable for nitrous oxide producing bacteria. The problem of emissions is also being compounded by biomass burning in agricultural practices, which accounts for nearly 10 per cent of human-caused emissions.
The agricultural scenario in India has become dependent on artificial nitrogen-based fertilisers and to make matters worse, organic manure is simply unable to prove itself as a dependable alternative. According to Indian fertilizer scenario 2014, an annual publication of the department of fertilisers under the Ministry of Chemicals and Fertilisers, the use of urea in the country increased by more than 50 per cent since 2000. Even worldwide consumption of nitrogen has witnessed an upward swing in the past century.
Apart from established adverse ecological impacts, nitrogen emissions can be very harmful for humans. According to World Health Organisation, nitrate-contaminated drinking water can cause reduced blood function, cancer and endemic goitre. Given these challenges, it is important for India to balance optimum use of nitrogen while minimising the negative effects.
In order to ensure this, there is a need to bring a change in the agricultural procedures, where incidence of nitrogen emissions is quite high. Innovation that is based on cutting edge research and development can help find solutions. For instance, corn farms in Maryland, United States, are experimenting with sensor technology, which collects in real time, data about the quantity of nitrogen needed by the plants, so that only as much measure of nitrogen can be administered.
Yet another method being experimented in the developed countries is the method of precision farming, wherein nitrogen use is rationalised and is used in small quantities. Similarly, India can also explore best practices of countries such as Bangladesh. Bangladesh utilises nitrogen tablets that are applied at root level which releases nutrients slowly. These measures and efforts will help India reach efficiency in the use of nitrogen.
It is also essential for the Government to aggregate the data on nitrogen pollution and usage. This will help the Government to draw up a suitable action plan and deal with the problem of nitrogen emission before it becomes an even more formidable threat.