Sunday, March 15, 2009

Regenerative Agriculture.

"The nation that destroys its soil destroys itself" (Roosevelt 1937).

Modern agriculture is based almost entirely on fossil fuels and natural gas. The former are used to run tractors and other kinds of farm machinery while the latter is cracked in a thermal catalytic process called “steam reforming” to make hydrogen which is combined with nitrogen to form ammonia, using the Haber-Bosch process. Haber received the 1918 Nobel Prize in Chemistry for this work which he developed with Carl Bosch. He has also been described as the "father of chemical warfare" for his work developing and deploying chlorine and other poison gasses during the First World war. Haber's wife, Clara Immerwahr, who also held a PhD in chemistry, opposed his work on poison gasses and committed suicide with his service weapon in their garden, possibly in response to his having personally overseen the first successful use of chlorine at the Second Battle of Ypres on 22 April 1915.

When I was at school we were taught it as just the Haber process, but Bosch has since then been recognised in this, probably the most important reaction ever performed in the world. Indeed, it was Bosch who transformed Haber's bench-top demonstration into an important industrial process to produce megatons of fertilizer and explosives. It is the fully developed system that is called the Haber-Bosch process. After World War I, Bosch extended high-pressure techniques to the production of synthetic fuel and methanol and in 1931 he was awarded the Nobel Prize in Chemistry together with Friedrich Bergius for the introduction of high pressure chemistry, e.g. the Bergius Process for converting coal dust to synthetic diesel by reacting it with hydrogen gas under pressure. Ammonia, as formed by the Haber-Bosch process, may then be oxidised using the Ostwald process to form nitric acid, and by the combination of these two materials, the fertilizer, ammonium nitrate is created. In fact this is a pretty dangerous material since along with other highly nitrogenous materials such as nitroglycerine, it is a powerful explosive. During World War One, the Allied forces dug trenches underneath the German lines, which they then filled with ammonium nitrate and detonated it, so that the explosion was heard in London, some 30 miles away across the English Channel.

While modern farming almost entirely relies on such synthetic fertilizers in "open systems", regenerative agriculture refers to "semi-closed systems": i.e. those in which inputs of energy, in the form of fertilizers and fuels, are minimized because those key agricultural elements are recycled as far as possible. Conventional agriculture is mostly "open" and hence large inputs are necessary since much of them are wasted and it is a matter of maintaining a sufficient productive density of fertilizers, pesticides, mechanical energy, to maintain production on poor soils with much of the living matter and natural animal life (earthworms, beetles etc.) gone. Indeed, modern soils have been described as dead, and only remain productive because of artificial and voluminous inputs derived mainly from crude oil and natural gas. As the latter sources of energy and chemical materials begin to wane and finally fail, so will most of the world's agriculture.

Although they are usually more energy efficient overall, regenerative systems generally need higher on-farm labour than open systems do, as shown by a study of 1144 farms in the United Kingdom and Ireland. From a conventional economic standpoint this is seen as a disadvantage and a disincentive to move over to using regenerative systems. However, in terms of relocalised communities and economies, so long as the labour costs are practicable, there may be positive benefits, in terms of the maintenance or creation of social capital and community livelihoods: i.e. the economy is retained within the community, possibly using some kind of local currency or barter system.

Off-farm inputs for regenerative systems are rarely zero, but are much less than is the case for the open systems of conventional agriculture. Soil organic matter invariably increases as systems become more closed, and both soil quality and health appear to be related to the amount of organic matter they contain. However, the relationship between soil quality and its crop fertility varies according to the particular soil system. In specific studies, mineral fertilizers (nitrates and phosphates) and tillage were applied to compensate for the loss of soil health, and yet as this declined further, and the soil became increasingly degraded, these mineral additions became ever less effective. It might be useful if set limits were imposed to the amount of off-farm inputs since this would provide a proactive address to various current environmental concerns, in particular the energy costs and degree of environmental damage that is caused by agriculture. The greater amount of soil organic matter in semiclosed systems compared with their open equivalents, results in larger sinks for both carbon and water. Thus, both aspects of taking carbon from the atmosphere to ameliorate global warming and needing to apply less water to the land, as global water shortages ensue, are addressed.

At the Rodale Institute, in Pennsylvania, the term regenerative has a more particular meaning, which is to regenerate the soil. Over a period of more than 30 years, methods have been developed that not only minimise external inputs but literally rebuild the organic components of soil and hence sequester carbon within it. According to their figures, if all of the world's crop-land were farmed using their practices, around 40% of all human CO2 emissions could be captured from the atmosphere and locked-into the soil, simultaneously improving its health and productivity. As we see in later sections, if a soil is healthy and "organic", where its natural biodiversity has been restored, the energy inputs are minimal since the natural ecosystem is able to maintain and farm itself: bugs and worms aerate the soil, and nutrients are passed down through the layers of growth from tree-canopy to forest mulch, while a diversity of natural plants naturally protects against pests, and the soil becomes better at retaining water, symbiotically at the depth of the root systems. An agricultural system is not usually "closed" entirely because it is normally intended to grow produce that is taken off the farm. However, in a fully self-sustaining (permaculture) arrangement, full closure is possible, where those living on the farm are fed, sheltered, kept warm and supported by their own labour and by natural inputs.

We stress that current farming practices are not sustainable, and for various different reasons, some of which are connected. Some soils in the American mid-west in the 1950s contained up to 20% of carbon, but this is reduced to perhaps a couple of percent or less now. This loss of carbon plays a significant role in breaking-down the essential structure of soil which leads to soil-erosion, decreases its ability to retain water so making regions more vulnerable to drought, and decreases the natural nutrient value of the soil. The situation is worse than this because the current practices of industrialised agriculture tend to break-down the soil carbon such that it is released as carbon dioxide. Indeed, recent data from the U.S. government suggest that around 20% of the American CO2 emissions are from food production, if actual farming procedures and the manufacture and use of chemical fertilizers and pesticides are all accounted for.

Results from the oldest run continuous cropping test plots in Illinois run counter to much prevailing thinking that supplementation of soil by nitrogen fertilizers helps the soil accrue and retain organic matter. The evidence is that it does not, but merely allows plants to grow on an increasingly mineralized template, whose organic carbon quality is not improved during the process. According to the International Panel on Climate Change (IPCC), farming and the use of agricultural land may be brought culpable for 12% of anthropogenic carbon emissions. It has been argued that the application of nitrogen fertilizer encourages the breakdown of soil fungi, so realeasing its carbon as carbon dioxide to the atmosphere.

Thus, we might not only lock new carbon into the soil using regenerative organic farming methods but ameliorate a sizeable proportion of our existing emissions simultaneously. The terms "soil health" and "soil quality" are used almost synonymously, at least in the media, but in fact their semantics devolve from more specific intentions. Since the quality, i.e. in terms of a chemical analysis of the elements present, and its biological and physical properties, does not vary spectacularly between different samples of soil, the term "soil health" might be favoured, since it represents a more holistic view of soil management, while "soil quality" is more static.

It is a satisfying thought, that rather than being a key problem element, farming might become the route to salvation from the problems of carbon-pollution, energy wastage and climate change. The British farming industry has been subject to various seemingly punitive measures during the past decade, involving the wholesale slaughter of herds of cattle to "deal" with the foot-and-mouth epidemic, and of other animals, e.g. sheep and pigs, in some overkill strategy that other countries notably France, just across the Channel from us, would not adopt. Friends of ours who farm in North Yorkshire did receive compensation for the loss of their animals, but for some farmers, unable to bear witness to the slaughter of herds their family had built-up over generations, the money was not enough, and equally so for some small farmers who could not survive the intermediate cash-flow crisis that prevailed, and literally did not, resulting in farming as the profession with the highest suicide rate in Britain. The restoration of British farming is the most pressing action for the government to take, if we are to continue successfully as a nation, particularly as the dearth of cheap fossil energy becomes unequivocal.

At the Rodale Institute, it has been shown that regeneratively managed organic soils have increased their carbon by around 1% per year to a total of nearly 30% over the 27 year duration of their study. In comparison, petroleum-fuelled land has at best accrued no additional carbon and in some cases the soil carbon content has declined over the same period. Soils that are richer in carbon tend to support plants that are more resistant to drought stress, pests and disease. The sequestration of carbon in soil is principally due to the presence of mycorrhizal fungi. These fungi are able to conserve organic matter by forming aggregates of it with clay and other soil minerals. In such soil-aggregates, the carbon is less vulnerable to degradation than as free humus. The mycorrhizal fungi produce a highly effective natural glue-like protein, called glomalin, which stimulates a greater aggregation of soil particles. It is further found that more soil carbon is accreted using a manure-based system than in a legume-based organic system.

In the first Rodale trial plots, carbon was captured into soil at a rate of 875 pounds of carbon/acre/year, using a crop-rotation using manure, and about 500 lbs/acre/year using legume cover crops. However, in the 1990s, it was shown that by using composted manure combined with crop rotations, organic systems can yield a carbon sequestration of up to 2,000 lbs/acre/year. In emphasis, fields worked with conventional tillage and which relied on chemical fertilizers actually lost 300 lbs/acre/year of carbon. 2,000 lbs of carbon is the amount contained in (44/12) x 2,000 = 7,333 lbs of CO2, and so each acre can remove this quantity of greenhouse gas from the atmosphere, per year, by trapping it in soil in fields.

While it would not be easy to do entirely, it has been stated that if all the 3.5 billion acres of tillable land could be so managed, 40% of all human carbon emissions could be sequestered in its soil. Roughly that amounts to 2,000 lbs/acre x 3.5 billion acres/2,200 lbs/tonne = 3.18 billion tonnes of carbon, which is 45% of the total of 7 billion tonnes of carbon emitted per year from burning fossil fuels, and is close to the above estimate. [As most of the calculations done in this book use metric units, 3.5 billion acres equals around 1.4 billion hectares or 14 million square kilometres (km2). This is around 10% of the Earth's land area]. The United States produces roughly one quarter of the world's carbon emissions, and has 434 million acres of tillable land. If a 2,000 lb/acre/year carbon-capture was achieved, almost 1.5 billion tonnes of CO2 would be sequestered within its soil to mitigate nearly one quarter of the entire U.S. carbon emissions from fossil fuels. Assuming an average mileage of 15,000 miles per year and 23 miles/per/gallon, this is the emissions-cutting equivalent of taking one car off the road for every two acres of land, or removing more than half the number of cars there are on the highways of the United States.

Regenerative practices are also shown to result in drastic reductions in energy use, according to Rodale Institute trials. For example, a 33% reduction in the amount of fossil fuel necessary to grow organic corn/soybean is found when cover crops or compost is used instead of chemical fertilizer. Even more strikingly, by means of a no-till, organic crop rotation approach, up to 75% of the fossil fuel normally required to grow standard tilled organic crops can be saved, resulting in lower costs fewer greenhouse gas emissions. The biggest energy input in a conventional industrial corn and soybean farm is nitrogen fertilizer for corn, and then herbicides for both corn and soybean plants. The ability of regenerative farming to become a major carbon capture medium and less demanding of fossil fuels has long term implications for global agriculture and its involvement in air-quality policies and programmes. Minimising inputs of fertilizers and pesticides means less pollution and a reduction in environmental clean-up costs and cleaner waterways.

By farming organically, the soil is regenerated to its natural condition. The input of chemical fertilizers and pesticides is either avoided or substantially reduced. These actions taken on a single farm extend well beyond the farm itself, and benefit the local environment and community. As the wildlands regenerate, wildlife and birds return and help to control insects and other pests. The local rivers and streams incur less pollution from agricultural land runoff, since less is being applied. Local communities may also be regenerated by implementing recycling organic waste that otherwise needs to be disposed of, e.g. on landfill sites, or becomes an environmental problem.

Related Reading.


Anonymous said...

Thank you for a very thoughtful and thought provoking post. I work with California growers to help them reduce their environmental footprint. My focus has been on increasing cover crop usage and planting of grass buffers for runoff management. To take it to the level that you discuss in your post, we are considering the use of performance based incentives to help growers assess the cost/benefit of each environmental practice they implement and, effectively, choose the "cheapest" and/or "best" practices for them and for the environment. I urge others to consider performance based incentives to measure agriculture's impacts and to point the way to greater sustainability. See for more info (and, no, I'm not on their payroll).

Professor Chris Rhodes said...

Many thanks for your comments. I have no axe togrind and am not on any payroll either, but I have come around to the conclusion that the only way forward is through agricultural change.

To encourage and support the change in farming practices that are necessary will require "incentives" of various kinds as you allude.

I am, however, beginning to feel a sense of hope rather than the despair looking for a high-tech solution had given me. The entire world population (particularly the industrialised, mostly Western nations) is going to need to live differently, but even though the horizon might seem clear, the transition there from the status quo needs very careful guidance and will not be easy.


Chris Rhodes.

Anonymous said...

Thank you Chris for your excellent post. I work as free-lance anthropologist in Guatemala, where we have been implementing regenerative agriculture practices since the 80´s. Our never-ending battle against chemicals continues and the information you share here will help as backup for ongoing battle to inform people. Thank you again, (we always respect authorship). Best regards.

Professor Chris Rhodes said...

I'm glad you found this post of some use. For various reasons, I think this is the way forward, in minimising inputs of various kinds to farming.

The world may learn lessons from what you have achieved in your country.

Best wishes,