courtesy: georgiaag.com
Fertilizers have become a mainstay in modern agriculture. Without it, the world would have food shortages.
But now fertilizers are been denounced as polluters and in some cases, where they are underused, as a man-made problem that hampers food production.
But let's look at the first instance. Fertilizers when used en masse, and indiscriminately pollute the waterways with massive quantities of nitrogen, phosphorus and other nutrients that causes pollution that damages man and animal alike. One of the most toxic effect is the increase in poisonous algal blooms, which are becoming more and more widespread. In effect, the great quantities harm fish in fresh water environments, but also in the sea, where they also contribute to acidification.
In contrast, countries that cannot afford to use fertilizers in sufficient quantities are facing food shortages and watching their land becoming eroded and impoverished in quality.
The UN is undertaking a study of the effects of fertilizer use in order to achieve a safer balance in the employment of fertilizers in agriculture.
Nitrogen fertilizer, the most common ingredient, has increased nine fold since 1960, while phosphorus has tripled. In addition, phosphorus resources are becoming depleted, posing a further dilemma on its usage.
As the population increases, use of fertilizer is expected to follow. That would exacerbate the already significant impact on the environment.
One of the problem in the study and planning logistic is to name an entity that would oversee the study and monitoring of fertilizer use globally.
The University at Yale has written studies in which fertilizers are identified as one of the three 'boundaries' which mankind has crossed and that are tipping the balance of the earth in territories from which there might be no return.
Fertilizer is one of them because as we spread fertilizer, we are in fact pumping more greenhouse gases into the air. This is because some oxides of nitrogen, compounds formed in the oxygenation of nitrogen fertilizer, are greenhouse gases themselves.
In fact the study at Yale University points to the fact that fertilizer directly affects life-supporting ecosystems, therefore being more important than some other pollutants.
The problem according to Yale University studies is the overuse of the compounds. of 80 million tons of fertilizer used each year, only 17 million actually get into food. The rest goes missing. Mostly this is because the fertilizer is used wastefully, but also because the new genetically engineered crops grow fat on the chemicals and therefore waste it. The nitrogen efficiency in the cultivation cereals has gone from 80% to 30% today.
What is more important, the overuse of nitrogen overwhelms waterways. In nature, most of the nitrogen in moderate quantities can be absorbed and neutralized. But the overuse has choked the waterways, which can no longer absorb it, so that the nitrogen saturates waterways, and they in turn are losing their ability to de-nitrify pollutants.
In the ocean, the fertilizer produces vast algal blooms, which release domoic acid a known poison, which linger on the ocean floor for weeks. This can cause kills of seals and birds, as they eat fish that has eaten algae tainted with the acid.
The areas contaminated thus, become veritable dead zones. The number of such zones has increased exponentially since 1960.
The only solution, then, is to put in place safeguards and controls that better manage the quantity of fertilizer employed.
source: Yale University - The NItrogen Fix/breaking a costly addiction
The Independent: 2.19.13
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