"We increasingly rely on inorganic fertilisers"

James Galloway, chairperson of the US-based International Nitrogen Initiative,tells T V Jayan that problems associated with nitrogen cycle disruptions aggravate when environment protection is segregated to specific issues of air, water or land

 
Last Updated: Saturday 04 July 2015

Of late, there is an emerging concern about increasing disruption in the global nitrogen cycle

Wherever you produce food and energy, they disrupt the nitrogen cycle. Increased food production produces more nitrous oxide -- a greenhouse gas which contributes to ozone destruction. This nitrous oxide in the atmosphere reaches our coastal waters -- through rainfall -- and causes eutrophication (it renders a water body unfit to sustain life).

At the same time, nitrogen is also needed by life forms. It's a very important constituent of amino acids and other complex biomolecules.

Another cause of disruption is that we don't put back the nitrogen we take through food into the soil.

Yes, that's true. In traditional farming, you grow crops and raise animals at one place. There are benefits from both. The animals also produce waste that is put back into the fields. So, a very nice cycle ensues. But since agriculture became industrialised farmers grow fodder at one place and raise their animals at some other. As a result, there is a large loss of organic nitrogen. In other words, you take nitrogen from one place, but it's not put back there. To compensate for this loss of organic nitrogen, we increasingly rely on inorganic fertilisers.

How do you compare the problems associated with nitrogen cycle disruption with that caused by disruptions in the carbon cycle?

Disruptions in the carbon cycle are caused mainly by carbon dioxide and methane, released by fossil fuel combustion. Methane is also produced from agricultural sources. These are associated with greenhouse effects and contribute to environmental problems on a global scale. The disruption in the nitrogen cycle also contributes to greenhouse gas effects. But in addition, disruptions in the nitrogen cycle lead to smog, acid deposition, coastal eutrophication and ozone depletion. All of them have serious effects on health and on ecosystems. It might be difficult for a country to solve a global problem such as the greenhouse effect. But problems associated with nitrogen are more at the regional level and they can be dealt with much easily.

Problems associated with nitrogen cycle are, in large part, results of ridiculously low nitrogen use efficiency

Absolutely. Actually, your question can be answered in two parts. We need to ascertain the exact mixture of nitrogen, phosphorus and potassium for specific crops. We need to ask ourselves: how does one apply these fertilisers so that most of it is retained in the soils as opposed to being lost to the water and the air? The second part is imparting agricultural extension education to farmers. It's not an issue for India alone, but for most countries. Even in the us, extension efforts have reduced over the last few years.

What about the human waste, particularly urine, which is nitrogen-rich?

It all goes to sewage treatment plants and septic tanks. Some solid waste does go back to the soil, when people use it for gardening. In the us, there have been some attempts to use animal manure, but nothing substantial.

What can developing countries such as India learn from the nitrogen-related problems of Europe and the US?

Let me try to answer this one indirectly. To begin with, India -- for that matter other developing countries -- should conduct a survey to find out what its nitrogen-related problems are. We know, by now, what the environmental problems associated with the break in nitrogen cycle are. So, there is no new science there. But the question is: do these problems exist in India, where and in what degree? How long have they existed? And, what would be the scenario in the next 10 years or so? You have to find out how altered your nitrogen cycle is and what are the exact consequences of these alterations.

The most important thing is to realise that a holistic approach can solve the nitrogen problem. In the us, and even in many other countries, environmental agencies are divided into different units such as one exclusively looking at air, another at water and so on.

But such segregation does not work in the case of nitrogen. There are nitrogen problems in the air, in the water and in the soil. When those associated with agencies that deal with water try to solve the nitrogen problem, they actually transfer the problem into the air. For instance, such people advise livestock owners to not release wastes into the coastal waters. But as a result, animal raisers may dump the waste in open garbage heaps from where nitrogen escapes into the atmosphere.

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