Farming and fertilisers

Posted: 13 December 2007

Artificial fertilisers have helped fuel the Green Revolution and increase food supplies. Global fertiliser use rose from 14 million tonnes in 1950 to 145 million tonnes by 1988.

• One half of all the commercial fertiliser ever produced has been applied since 1984.

• While there is potential for increasing world food supply by increasing fertiliser use in low-production countries, there can be a cost.

• Over-fertilisation is a problem in the developed world where affluence means farmers tend to over-fertilise because they are unaware of the specific nutrient content of soils or the needs of the crops.

• Agriculture accounts for by far the largest amount of human-generated nitrogen - some 86 per cent.

• About half the fertilizer applied to fields never even makes it into plant tissue but ends up evaporating or being washed into local watercourses.

• As a result there has been a dramatic increase of nitrogen in water supplies in some parts of the world. This threatens both human health and the environment, with fertilisers leading to the growth of undesirable plants and algae in many water bodies.