Regenerative Livestyle Blog

Category Archives: Agriculture


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Nitrogen cycle…

In the Core Concept document of our Graduate diploma for Sustainable Practice are listed Nine planetary boundaries, three of which are in the red zone “Li-mit ex-ceeded“! Climate change, Loss of Biodiversity: Yes this is sad, I know lots about these. And Nitrogen cycle. Exceeded by 200% ! What is that???? I need to go back to my biology textbooks and discover that many seemingly different problems are all Nitrogen issues. Acid rain? Water pollution by nitrates? Lakes eutrophisation? Ocean dead zones? Have you heard of them? I had, but had not connected them yet: they are part of the HUGE nitrogen cycle issue…

Nitrogen

Nitrogen is a crucial element in all living things, essential part of the structure of proteins and nucleic acids. Atmosphere is made of 78-80 % of nitrogen gas (N2). But this molecule, N2, is so stable that it is rarely available directly to organisms. It is in mineral form, nitrates (NO3) , that nitrogen is assimilable/available/incorporated to plants and animal tissues.

Natural cycle

How is Nitrogen oxidized to its mineral form: through a several steps process of ammonification and nitrification.

Ammonification: Nitrogen fixing bacteria fix atmospheric nitrogen and transform it to ammonia NH3. These bacteria are either:

  • Azobacter, found freely in the soil, producing 25kg/ha/year of ammonia
  • Rhizobium, living in root nodules of mostly legumes, producing 500kg/ha/year

Ammonia also comes from animal excretions (urea) and the action of decomposers on dead organisms.

Nitrification: Nitrifying bacteria, nitrosomonas, transform ammonia in nitrite NO2, then another nitrifying bacteria, nitrobacter, transforms nitrite to nitrate NO3, which is assimilable by plants and animals.

Of note: Lightning discharges can oxydise nitrogen directly to nitrate which ends up in the soil, but accounts for only 10kg/ha/year.

Denitrification: The last part of the cycle is the process of denitrifying by anaerobic bacteria pseudomonas, that return fixed nitrogen to the atmosphere. They can evacuate only 20% of soil nitrates.

The cycle is imperceptible and yet fundamental to life and growth. I am not sure I will remember these names, but I understood there is a variety of different of bacteria and an order in the process therefore the cycle can be bottle-necked.

Industrial N-fixation

At the end of the 19th century, it was discovered that it was possible to transform atmospheric nitrogen into ammonia. Its role on plant growth was identified but its making was long and difficult. Fritz-Haber discovered in 1909 how to make it industrially (at great pressure, at 600°C, in an iron catalyst and combined with hydrogen). It produced an explosive that is said to have given an advantage to the Germans during the wars.

After the second World War, it started to be used in agriculture as a fertilizer. Agronomists promoted its use to increase much needed food production yields. My Mum recalls when, in the 50’s, her respected teacher had spread nitrate powder on a field on a hill to form the letters A Z O T E (French for nitrogen) , so that a few months later, everyone could see from far away how greener the grass was when fertilized with nitrate. During the next forty years, the quantity of fertilizers spread on fields has increased fivefold. Today 100 millions tons of nitrogen fertilizers are produced and spread each year. The nitrogen deposition has increased:

  • over 200% in ecosystems,
  • 250% in the atmosphere (in various forms),
  • 400% in rivers…

Attention ! Not for the faint hearted!

Problems in waters

Nitrogen that is not used by plants is sent back to atmosphere by pseudomonas at a rhythm of only 20%, as seen above. The rest leaks in stream, lakes and aquifer waters. It causes:

Eutrophisation: in low stream waters, accumulation of nitrates grows algae which consume all the oxygen from the water and lead to the death of other aquatic life.

Water pollution: Human consumption of nitrates is dangerous as it becomes nitrites which inhibits oxygen assimilation in infants and, accumulated as nitrosamines, is carcinogenic.

Because of its long term impacts on food webs, nitrogen inputs are considered a major pollution problem in marine environments.

Problems in the atmosphere

Various Nr outputs in the atmosphere result in a decreased atmosphere visibility due to fine particule matters and an elevated ozone concentration. Both affect human health (respiratory diseases and cancers), global climate change and decrease agricultural productivity (due to ozone deposition). And acid rains further damage ecosystems and contribute to ecosystems acidification and eutrophisation.

Today, over one third of N2O emissions results from human activities, mostly from agriculture. But combustion of fossil fuels, in automobile engines and thermal power plants also produce various nitrogen oxides (NOx).

Nitrous oxide N2O is of particular concern because it lives up to 120 years and is 300 times more effective than CO2 as a greenhouse gas.

Problems in soils and ecosystems

Adding nitrates to soils no longer improves productivity because soil also needs carbon and oligo elements to “digest” it. It only acidify the soils and leaks away. It is now counterproductive.

Acidification causes changes in the plant communities, aluminum toxicity, habitat loss, decrease in biodiversity, water turbidity, even hypoxia and dead zones…

We could add that this production consumes 2% of the world annual energy supply and have a thought for this well-intentioned teacher!…

The results of the first European evaluation for nitrogen Report announced during the Edimburg Climate Change and Nitrogen conference in April 2011 show that nitrogen-caused damaged are estimated at 70 to 320 billions of Euros each year, only in the European Union, that is 150 to 740 Euros per person and per year, that is more that the double of the benefits created by nitrate use in European agriculture.

Solutions

Solutions exist even in seemingly desperate situations. David Holmgren explains how in Africa, soils have been exhausted from the growth of a corn introduced to improve food supply. After a short time, nitrates were added to help the diminishing productivity but not only they were not affordable for the community but they also badly damaged local -rare- waters. Nitrogen-fixing legumes were introduced and used in crop rotation, which in two years restored the soil fertility, while adding nutritional value to the locals and the water improved.

Solutions need integrated approach on agriculture, transports, water sewage and individuals choices: work on Nr storage and de-nitrification in all areas, changing agriculture practices, reducing overall animal breeding, so eating less meat and dairy products.

As many years of research have shown, once nitrogen is oxidized, it globally “cascades through the environment” as detailed in this UNEP document http://www.unep.org/yearbook/2003/089.htm and addressing the issue is now recognized as one of the biggest challenge today.

Sources

  • Guide Illustre de l’Ecologie, by Bernard Fischesser. Paris: La Martiniere, 1999.
  • Year 12 Biology 2006 Student Resources and Activity Manual. Hamilton, Biozone, 2005.
  • Permaculture: Principles and Pathways Beyond Sustainability, by David Holmgren. Hepburn: Holmgren Design Services, 2006.
  • Internet links included


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Economy & Sustainability

With an initial education in economics, I have a interest in the links between sustainability and economics. As well understood and skillfully demonstrated in the “Story of Stuff“,  consumer society is unsustainable.

Capitalism and the environment

Why don’t we stop over-consuming then? Because consumerism is intrinsec to the predominent economic system, capitalism. Here is how it works.

Capitalism is driven by profit. Profit is the difference between the market price a good (or service) is sold and the price needed to make the good (or service). The price to make a product (or service) comes from its raw materials and its work force, part of the machines and the processes needed to create it.

In agriculture, a fertile land will have high yields, with low production costs and create lots of produce. When demand for the produce grows, farming need to occur in less fertile lands, the work is harder to obtain the produce. The market price will rise so that this farmer can survive. Yet, for the fertile land farmer, the costs remain the same. Here are his profits. When the land fertility decreases, so do the profits.

In manufacturing, the costs can be lowered by asking workers to work harder and pay them minimally. Of course this is limited to the survival of the workers and social unrest. Many strategies have been developped to keep this to a minimum. From offering workers house and food near the plant so that they work longer hours, to make them happy enough with a brainwashing television, to delocalisation of course. With social awareness and movements this has become a limit so profits stagnate…

The other way to lower costs is to get the cheapest inputs. This is the whole colonisation business. Arrive with arms and declare it’s your country now and you can just take whatever resources you want for free. Over time, things have to be a little less obvious, hardly. But today there are rich and poor nations.

Nature has always been considered a reservoir of goods, the only cost of it is to extract it. Yet it is harder and harder to extract it, so again profits stagnate… Here also come the externalities issues, the process of not paying the whole cost of the products, for example by dumping waste in the air and rivers, or by letting the health system look after sick workers etc. These have been timorously regulated by governements in fear of delocalisation.

So we see how profits tend to decrease. To compensate for that, entrepreneurs need to find new ways of improving productivity (robotisation – inducing unemployment) and to invent new products (and sell them – consumption society). They need GROWTH. All is linked and inherent to the current economic system. And all in crisis…

From crisis to shift

OK – I did simplify but basically, that’s how it works.

While the coming of the crisis was visible way back in the 1960’s, we can understand the interest of keeping the consumerism system going by any mean to become richer. And in many ways, many people did become richer- which does not mean happier. But many people also became poorer, and the environment pays its tribute! The resources are finite, and the planet has natural boundaries, some of which are exceeded.

What we have…                  What we need….

   

 A major shift is required indeed, both in systems and mentalities…

Sustainable Economies

It is not new. In 1973, E. F. Shumacher published Small Is Beautiful: Economics As If People Mattered which promoted the use of local and appropriate technology to empower the people in a world hit by the energy crisis and globalisation. The ideas are developped today by the New Economist Institute and its large network.

The concept of sufficient economy was supported by the King of Thailand and based on buddhist ideas, with three key principles: moderation, wisdom and built-in resilience. It has been developped in the Thailand Human Development Report published in 1997 and  adopted in the 10th National Development Plan as summarised below:
 

Here is an interesting article on “rethinking growth”, an interview of Herman Daly, ecological economist, published on Seed Magazine http://seedmagazine.com/content/article/rethinking_growth/

For the people, it is important to become active consumers. Do you really need to buy it? Choose where you spend your money wisely. Easy no? Concepts of frugality, simple living, intentional living, permaculture, the slow movement, alternative economics (and more – please suggest! ) are all different ways to deal with a common goal of moving out of the capitalism crisis.

Sustainable Practice in business is about finding innovative out-of-the-square-thinking ways of curving the line into a circle.
The line is: Take resources -> transform them into a product -> sell them -> products are used and dumped in landfill.
The circle is: take recycled resources -> process them with least waste -> use them -> recycle them

The example I preferred -so far- is Interfaceflor : from traditionnal carpet laying that goes to landfills in 10 years, they committed to Zero waste. Not only they choose non toxic materials, but they’ve arranged a way to separate materials after use so that they can be reshaped in new carpet. They lay squares of carpet so that used parts (entrance and ways) can be swaped with less used parts (corners) easily. Furthermore they found a way of recycling all their carpet: they ensure its maintenance overtime. Quite smart!

 I believe taking sustainability seriously is a wonderful opportunity to create economic and social systems that work in the long term for everyone and within the natural environment. It does not mean revolution. It does not mean “go back to the candle” as sceptics say. And it does not mean recession, as many fear. If we are to cover all basics needs for our growing worldwide population, there is huge scope for growth, which does not have to be destructive. We need to be aware, smart and innovative, and share… A big shift indeed! 

Knowledge, technology and tools exist and are taught in the Graduate diploma for Sustainable practice at Otago Polytech. I am studying towards it because I want to contribute to the shift.

Florence Micoud