Posts Tagged ‘climate’

Sausage, biochar and recycling.

December 19, 2012

I fancied a sausage. There is fire in the fire-place, I can grill there. Place it in a metal folie container, then I can do other things. But the heat and fire was more intense than expected, and when I looked the whole sausage was on fire. Black as coal. But I could extinguish. And – underneath the coal layer  it was quite fine. But smaller.

It made me think about biochar. That is a kind of burning (ok – pyrolysis), preferably of biomass, some gases are collected and there is a rest, biochar. Applied on soil it is stable for a long time. The carbon dioxide captured by the biomass will then be permanently withdrawn and stored as carbon in the soil. It is a way to store carbon and reduce climate gases.

But I have a sceptical thought: You have let us say one kilo biochar. You could burn it in an energy production unit and in that way save one kilo fossil carbon otherwise needed. Or you could store it in the soil. Is the difference important? Some say so, also scientists and professors, but I am not totally convinced.

Biochar should make the soil more fertile. It has a large active surface (but not as large as clays, it absorbs water and improves soil structure (but what amounts are needed to make practical impact?). There is a nutrient content, but that factor is not much mentioned. The P and K present in the biomass should end up in biochar.

Wonder products make me sceptical, maybe too much.

Maybe sewage sludge could be used for biochar?  That should give a product combining carbon, P and K for agriculture.  The metals will also be there, I am afraid.

An important environmental problem is organic substances (hormones, medicins, the chemical palette used in our society) which pass the sewage work and end up in waters. Promising attempts have been made to absorb at least some of them by means of active carbon. That sounds expensive. Is biochar active?

Then you could imagine a nice combination: Biochar is added in the sewage treatment, it absorbs harmful organic substances and ends up in the sludge. The sludge is incinerated, the biochar gives extra energy, all organic substances are eliminated, the ash is extracted and a pure P fertilizer results. Especially advantageous would be if the biochar is produced by another sewage work where burning and extraction is not feasible. Biochar production could be more smallscale. You get a more transportable product and the P from both works are taken care of.

If someone will use this idea, kindly refer to this blog.

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Catch crop effects in a wider context, cover crops.

November 21, 2012

Sweden has since several years a catch crop program. It has been focused on reduction of nitrogen leaching. A compensation is paid to the farmer to encourage the practice.

In previous posts on this blog the more general favourable effect of catch crops, on soil structure, on soil life, on organic matter content has been advocated. It is very encouraging that these issues now are discussed an recognized in an official report.

Catch crops can be transformed to cover crops, where even a harvest can be taken. Also this is mentioned, although the research and experience on this is scant. However,  at least in some favoured areas we can produce a second crop after for instance cereals.  Forage can be preserved as silage and used for biogas,  if  local biogas plants are established. In this way agriculture can substantially contribute to energy production and climate gas improvement.

Cimate argument.

November 10, 2012

 

 

A column in Astronomy (Bob Berman):

Visiting a top scientist in Boulder, Colorado, Rodney Viereck.

They discussed the temperature development of the planet. Berman asked if the increase could be caused by changes in the sun. But Viereck showed that our upper atmosphere is colder now than 100 years ago. If more heat is captured and held in the lower atmosphere the upper layers will be cooler. This effect is caused by climate gases, absolutely not by the sun.

Perspectives on Global Warming.

November 5, 2012

A current goal is “by 2020 not more than 2 degrees warming compared to pre-industrial times”.  A very conservative figure could be less than 1 degree per 100 years.

The geological history tells us about previous global climate changes. 55 million years ago something called PETM (Paleocene-Eocene Thermal Maximum) occurred. The average temperature of the planet increased by about 5 degrees. The probable cause is widespread volcanism and emission of carbon dioxide when the the Atlantic was opened up. From our distant viewpoint it seems dramatic but short, only 200 000 years. It lead to great changes of life on earth. But then the temperature was normalized again, when the carbon dioxide had been absorbed by the sea and land systems.

The change occurred during the first and last 10 000 – 20 000 years. If we say 10 000 it means a temperature rise of 0.05 degrees per year. Compare with our goal mentioned above.

In earlier times still more dramatic events occurred, seen in geological timescale. 250 million years ago, when the Perm era changed to Trias and only the forefathers of the dinosaurs had begun to form, the temperature was raised by 15 degrees in several steps. The reason again is probably intensive and longlasting volcanism, this time in Siberia. Coal layers in the area gave large amounts of carbon dioxide. The temperature in equatorial seas increased to 40 degrees, in land areas maybe 10-15 degrees more. This is a main extinction event in our global history. But the change took time, something like one degree per 10 000 years, which should mean 0.01 degrees per 100 years. This heat period lasted, with variations, four million years.

What is happening now is more intensive and dramatic than even PETM.

But we don’t notice it. Or do we?

(Background: several issues of Science)

The “Book” is complete, almost

October 9, 2011

Soil and crop management for today and tomorrow.

That is the bold title of the work. Not so detailed, but maybe comprehensive. I intend to add more links to add to the contents.

Main points.

It is necessary to be ecologically efficient. Reduce nutrient losses, use chemicals with care and restraint.

Have high production. That is good for both the soil and the economy.

Put prices on secondary effects. Example: soil organic matter is beneficial. But it should be quantified in economic terms to come into the planning process.  “Soft” information is difficult to use.

But there is a lot we all can do in our different positions. If you can do nothing else – write a book.

There is a link to the book to the right downwards.  Blogroll.

Climate smart – or not?

November 26, 2009

Don´t eat rice. Avoid beef. All for the sake of the climate and our planet. Many well-meaning voices are heard. But the issue is not simple.  Let us think globally and start with rice.

The problem with rice is that the cultivation in flooded paddies gives methane emission. The best varieties are adapted to paddies and farmers in paddy areas don´t have much choice, now. And the whole society and economy is based on rice.

But something has to be done. Develop new varieties adapted to drier land. Change the cultivation technique. Or develop a replacement for rice to grow in the warm season. But time is needed. We should not kill the patient before working on a cure.

We could also discuss the consequences of replacing the world rice with wheat. That would mean cultivation of new land which probably would give higher climate impact.

 

And the cows? Not easy. Especially if the climate effect of methane has been underestimated. But in the global context – the grassland area is larger than the arable area and what should become of the grasslands of the world if no ruminants should use them? Bushland? And what about the millions of people living on cows, goats and sheep? Maybe again time is needed. Now when the problem is apparent work is going on to change the situation.

I guess that in 10 years we will have animals emitting less methane.

Zero greenhouse gases from plant production – a possibility.

November 25, 2009

 Use of agricultural by-products as straw for bionergy opens up for a plant production with climate neutrality. The losses from soil and use of inputs will be compensated by the saving of fossil fuels in the total picture.

 However, there is a something to consider, the soil carbon. In most agricultural soils the soil carbon needs maintenance, and for that reason return of straw is important. But it can be replaced by cover crops, with advantage. Adapted in the right way we may get the following: Some yield increase, improved soil carbon and soil structure, soil surface protection, income from straw sales, in total low or even negative emissions of greenhouse gases for the whole system. Required base: a calculation of carbon balance and development.

Planetary boundaries. A presentation also in farm journals.

November 13, 2009

 A report by internationally renowned scientists give tentative figures for ecological boundaries. One of those is inflow of active nitrogen to the global ecosystems. The current figure is 121 million tons (fertilizers plus biological fixation). The tentative threshold value is 35, less than a third. The fertilizer nitrogen is currently a little below 100 million tons and the demand is projected to increase by 3 million tons every year. Increasing population  gives increasing demands.

Maybe some shake up is needed.

The figure 35 says nothing about how to manage food production, it is just an estimate of  a safe value for the global ecosystems.

However, we get another reminder of tough challenges ahead:

Efficient nitrogen use in agriculture. There are improvements, but not enough.

The animal production. The most inefficient production in ecological terms is the most fast-growing. There will be questions about this. But cheese and beef and bacon are valued.

The nitrogen in waste. The main aim of agriculture is food to man. The annual nitrogen turnover is about 10 kg per person. The 9 million Swedes release 90 thousand tons of N, to be compared to 160 as mineral fertilizer and in total about 120 released from farm animals, of which 40 is directly wasted as ammonia. There are efforts to reduce losses, but so far very little nitrogen except manure is recycled.

Maybe, for waste nitrogen, an alternative is to denitrify it to nitrogen gas and get fresh active nitrogen by industrial or biological fixation.  It depends on energy relations and emissions. Which is best?

Natural systems – the most important resource of the globe?

June 10, 2009

Not for clearing to agricultal land but for keeping. This was mentioned in my previous post. And  now a study presented in Science Magazine arrives att this result in a global simulation (23 May, page 1183. Implications for limiting CO2 concentrations for land use and energy).

Clearing natural land means release of stored carbon and nitrogen which is negative for the climate. And in addition there is the biodiversity issue.

This means that it is important to efficiently use the the land which is under cultivation. The study sees a continuous increase in agricultural productivity as a necessary prerequisite.

This is a challenge – a challenge not to go too far. Not to hunt for the last possible kilo of yield or the last dollar in shortsighted profit. That is not what the globe needs. A more longterm view is necessary.

LET US RAISE THIS ISSUE IN THE POLITICAL-ECONOMICAL DISCUSSION.

This is much more important than the quibbling about organic – conventional. Unrestricted market driven conventional compromises environment and sustainability. Dogmatic organic would be a disaster if implemented in total in the world we have. What we need is either reformed organic (ecological) or modified (integrated) conventional. And that is possible if the dogmatics in both sides (organic fans and free market dogmatics respectively) widen their views,

A high-producing crop production i south Sweden can be carbon neutral with full food production, provided straw is used as bioenergy and cover crops are used to keep the balance of soil organic matter.

Bioethanol – good or bad?

May 12, 2009

A study in USA shows that gasoline is better than ethanol from corn  (Science 1 May). Already this has caused headlines in daily papers. “Ethanol from agriculture is out”.

But the issue needs a second consideration. In this study it is presupposed that a reduction in food production needs compensation by turning grasslands and forests inte agricultural land. In the long run this is so, which has been previously discussed in this blogg (tag Climate). But let us widen the perspective. This way of accounting means a large secondary environmental load also for a more low-producing  organic agriculture.

Maybe it is more important to see a mosaic of opportunities. Bioethanol from agriculture can be an important forerunner for alternative fuels. But in the long run it seems necessary to use the arable land for efficient food production.