Scientists say the nitrogen kills fish by depleting oxygen levels in water and may also contribute to climate change. As the Earth’s population has increased, farmers have increasingly turned to nitrogen fertilisers to improve crop yields.

Professor Donald Canfield from the University of Southern Denmark is the lead author of a paper outlining the problems in the latest edition of the journal, Science.

He says the use of nitrogen fertilisers has more than doubled the amount of nitrogen on Earth. “We now have the possibility of fertilising large tracts of land which wouldn’t have been possible to fertilise before,” he said. “But the bad thing about it is that the nitrogen that is added to the soils often runs off the soils and then into coastal areas and into lakes where it utrifies them. “[It] causes a lot of productivity of algae, which in turn can cause the oxygen in these environments to go down to very, very [low] levels and cause fish kills and all sorts of things.”

Professor Canfield says other excess nitrogen is being pumped into the atmosphere as the greenhouse gas, nitrous oxide. He says naturally occurring micro-organisms will be able to clean up the excess nitrogen that humans have created, but it will take many decades. He says farmers need to stop the run-off of excessive nutrients.

“It used to be in Denmark that people would fertilise during the fall because that is when they had the fertiliser ready and that is when they could put it on,” he said. “But by doing so, a lot of the fertiliser was lost and ran off into streams and not used by the plants the next spring when they started to grow. “So just timing the fertilisation together with the plant growth season can help a lot.”

In Australia, a report suggests rotating crops with plants like legumes that are able to process the excess nitrogen; it also suggested using selective breeding or genetic engineering to create plants that use nitrogen more efficiently. Professor Peter Grace from Queensland University of Technology’s Institute for Sustainable Resources says the report’s recommendations are good, but some will not suit Australia’s environment and others will not be viable for many years.

In the meantime, he says Australian farmers need more information about the most efficient ways of using nitrogen fertilisers. “Farmers are across this issue because it is profitable. It is what is in their back pocket,” he said.

“But on the other hand, they do need education in terms of when to apply the nitrogen. “There’s also climate variability. There is a whole lot of different environmental interactions that need to be taken into account. “Farmers need information and it’s not as simple as just getting on the web. Farmers need actual information provided by agronomists and extension agents out in the regional areas.”

Professor Grace says state and federal governments have been cutting funding for such services.

You would have thought any government with half a brain would have dedicded that if koalas – that have a minimal foot-print – can lay waste of their environment, that so too could humans on the mainland.

Of course we’re a lot ‘smarter’, because we can drive to another region, use fertilizers and broad acres farming and if that doesn’t work, sell of some of our resources (which will also eventually run out, but hey, that’s someone elses problem) and buy food in from overseas (which we now do to the order of about 27% in fruit and veg).

But really, should the total focus just be just on water or the almost depleted phosphates used world-wide for broadacre farming … what about topsoil ?

Topsoil is pretty much the cream of the soil, the culmination of various micro-organisms working together to break down wastes to prepare a vegetation nirvana; depending on nutrients, acidity and PH balances, a wide selection of crops can be grown directly and indirectly (bovines etc) for human consumption, but what happens when the micro-organisms – which work to a fairly exacting standard – can’t get access with enough raw materials to make more topsoil ?  Iowa is the leading ethanol producer in the USA and they calculated that roughly every 4 litres of ethanol (they produce) translates into a loss of  8 kilos of topsoil.

We read of the extenction of species all around the world; we know that in China, millions of farming families have been moved from productive soils to make way for factory’s, cities and the world’s largest dams; we knw the UN has reported that biofuel production now sees man pushed aside for the wealthy to drive, so is there anyone out there not affected ?

A recent article in the UK projects that Britain will face a food crisis as the world’s topsoil vanishes in 60 years and the understatement of the century …leading to a catastrophic food crisis and drastically higher prices for consumers !  Just last year,  Sydney was blanketed by thousands of tonnes of soil during its worst dust storm in 70 years; a couple of years earlier it was Melbourne and back in the 70′s Adelaide was covered in a blanket of redsoil.

So how did we get to such a state of affairs, of chronic soil mismanagement and over farming causing erosion; is it possible we ave tipped the balance and this too contributes to climate change; ot is it just that we humans have pro-created to such a level that the micro-organisms can no longer keep up and there will not be enough topsoil. Scientists estimate some 75 billion tonnes of soil is lost annually with more than 80 per cent of the world’s farming land “moderately or severely eroded”.

A University of Sydney study found soil is being lost in China 57 times faster than it can be replaced through natural processes; in Europe the figure is 17 times, in America 10 times while 5 times as much soil is being lost in Australia, but we never had the ‘reserves’ of topsoil of the other countries. Increased land pressures aimed at compensating global production losses would likely mean it top soil will run out faster. Britain imports about 40% of all the food it consumes, a figure that has steadily risen over the past few years and yet Britian has long been acknowledged as having good reserves of top soil and corresponsing rainfall.

John Crawford (Professor of Sustainable Agriculture at the University of Sydney), said it was ‘unknown how long soil will last; it could be as little as 60 years and that is a scary figure because it is not obvious that we have time to reverse decline and still meet future demands for food; it is not an exaggeration to say that soil is the most precious resource we have got, and… (we) are not up to the task of securing it for our children never mind our grand children’.

But how do we rest soil and help it take in more carbon; how can we help soil to be more fertile; while organic farming and permaculture could be part of the answer, how do we feed the current population of some 6.8 billion people ? World stock of cereals dropped to a 30-year low, with demand for wheat and rice outstripping supply for the past 6 of the last 7 years. Demand always results in prices rocketing, which has already sparked civil unrest in many countries.

So think next time before you throw vegetable wastes in the garbage bin; use that and lawn clippings and even some discarded newspaper to make into compost and eventually did into the soil; if a few do it, its small, if 6 billion people do it, it will help, but here in Australia we are eating our topsoil quicker than it can be prepared; we need to send our body wastes back the the land from whence they came to bring back the balance …  it starts with you.