Wicking beds

Files added 28/12/2010

To better understand the relevance of the wicking bed technology you may like to read the preface ‘a sustainable world’.

The wicking bed is an innovative technology, essentially a new agricultural system. They give increased food production, with significantly less water, recycle organic waste to provide plant nutrients, reduce chemical run off into our rivers and sequester carbon into the soil, helping to reduce climate change.

	An underground water reservoir is filled with organic waste and water. Nutrient rich water, essentially a compost tea wicks upwards to the root zone. The soil is maintained moist, not saturated giving increased food production. Water can also be harvested by directing run-off into the wicking bed. See wicking_bed_technology.pdf
	Significant quantities of water are stored in the reservoir so watering can be less frequent and making the beds better adapted to erratic rainfall. Production is higher than conventional systems with less need for external inputs of water and fertilizer.
	Any water applied is contained in the reservoir so run off into aquifers or the river system is reduced. Instead urban waste, sewage and forest trimmings to reduce bush fires can be recycled, preserving nutrients.
	Significant quantities of atmospheric carbon can be sequestered and embedded into the soil. Carbon is embedded into chemically stable humus by micro biological action which thrives in the moist conditions. See carbon_capture
	Wicking beds are well suited to developing countries improving their food security while allowing then to expand their economies while controlling emissions. This removes on of the major impediments to obtaining a global agreement on climate change. resolving_global_warming.pdf
	Wicking beds are widely used in Australia, largely by environmentally sensitive amateur growers. To achieve the full benefits of reduced green house gases and pollution commercial farmers need to install wicking beds on a significant scale. How to achieve this scale is discussed in large scale adoption.

A sustainable world

The world has really made very little progress since Kyoto as shown by Copenhagen, often due to well intentioned viewpoints which are understandable in principle but result in damaging consequences. For example the use of eco systems and soil carbon capture as an offset was strongly opposed by certain green groups as it would allow the rich polluting countries to continue with their extravagant life styles without making any serious reduction in green house gases. Good intention – bad outcome.

It is worth taking a moment to create a holistic perspective. Currently we have a global population of over 6 billion expected to rise to some 9 billion by 2040. But these figure do not show the real problem. The current rise in green house gases has been generated by the 2 billion of so affluent consumers in the developed countries. The developing countries are becoming more affluent by the day, just look at the progress in China, so we can expect that by 2040 we will have some 8 billion affluent consumers, not just emitting green house gases but consuming our finite resources.

Mankind has showed remarkable resourcefulness in tackling major problems, and there is wide spread optimism that science will some how resolve our problems. This view is most strongly held by population at large who may not be too familiar with the way science and technology work in practice. Our political leaders have also learned never to move to far ahead of public opinion, becoming trend followers rather than true leaders.

Science is concerned with truth and scientists go to great lengths to guard their statements, often to the extent that the real meaning is not clear to the public. I have had a passionate interest in the process of science but was trained as an engineer. One of the first lessons a rooky engineer learns at college is that engineering is not about unassailable truth but managing ignorance. Engineers are rapidly taught about ‘safety factors’ the margin between designed (or predicted) performance and expected requirements. Engineers are not good at public relations but they did have the sense to use ‘safety factor’ rather then the correct term ‘ignorance factor’.

If engineers are designing a component, say an aircraft wing, they do not know really know how strong the final geometry will be, how uniform the material is, what load may be experienced in some storm in flight. So they use this ignorance factor to design a wing which does not fall to bits in flight. The fact that air travel is incredibly safe; - planes simply do not fall to bits in the sky. This is all because of the skill of engineers in managing ignorance.

Science is about managing truth, engineering is about managing ignorance. My television has been bombarded with large scale tragedies, floods in Pakistan, China and Europe, fires in Russia, heat waves in the US, and our horrendous bush fires in Australia. No respectable scientist, with his concern for truth, is going to say that these tragedies, in which thousands of people have died, are the result of climate change. They best they can say is that it is consistent with what is predicted with climate change. These words are reassuring to the general public who interpret what the scientists, the experts they trust, are saying is that these tragedies are not proven to be the results of climate change. This leads to a policy of inaction.

An engineer, used to managing ignorance, would say that these tragedies are extraordinarily likely to be caused by climate change, things look as thought they are going to get much worse so we better start taking real action now to minimize and mitigate these disasters in the future.

Same probabilities, different interpretation, very different outcomes.

You may not like the engineers caution but before you dismiss it think that this is the reason why you can step on a plane knowing that it is not going to fall to bits in the sky.

Look at the situation when it is the other way round. You have probably experienced some product you have paid good money for that simply does not do the job you bought it for. The reason is almost certainly that the company is run by a finance person, who asks the engineer why the product costs so much and receives the answer that it is because he his managing his ignorance. The finance man then says he is not paying the engineer to be ignorant, go away and design the product to this price, so it can be sold at a profit.

This is not a joke, this is the way the real world works. But so we really want a world in which people are being drowned, burned or starved to death simply because of economics.

Climate change is just one component of having a sustainable world. Here I want to look at a technology, the wicking bed, which will help us to be sustainable.

It has the potential to remove significant quantities of carbon from the atmosphere, helping to mitigate climate change, it improves our food production capacity, it recycles our waste back into food and reduces water pollution.

It may offend the delicacies of the purist by possibly giving an excuse for polluters to continue pollute but it is pragmatic. It is like having a picnic on a railway line debating the probabilities of a train coming and becoming worried and miserable. The pragmatist simply makes the effort now, gets up, moves to a safer place and enjoys life.

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Carbon Capture in the soil

There is a wide spread view that simply capturing carbon in the soil will both improve soil quality and mitigate climate change. There are truths in these views but the situation is more complex than simply increasing the level of soil carbon in the soil, total soil carbon content is only part of the story.

What really matters is the form of the carbon in the soil. If the carbon is in an unstable form, e.g. readily digested by bacteria, any benefits for climate change and food production is limited. If it is a stable form, what we know as humus, it will have long lasting benefits for both climate change and food production.

The critical factor is not the total amount of carbon in the soil, but the amount of stable carbon or humus in the soil.

Background

In the mid seventies Australia suffered severe dust storms loosing millions of tonnes of top soil.

I started a research project on how to regenerate top soil, using a block in which al the top soil had been lost by excessive grazing by goats leaving the underlying clay base. See www.waterright.com.au/soil_regeneration. The characteristics of the clay were only to clear. When dry it was like concrete almost impossible to work, but when wet it would become little more than an unworkable gooey mess. Plant growth was extremely poor.

The carbon or organic content was very low however simply adding organic material or even the so called clay breakers had little change. It was simply a mix of organic material and clay with essentially the same characteristics. However using the appropriate process the characteristics could be completely transformed producing a soil which is easy to work, wet or dry, exhibiting reduced density and significant elasticity (springiness) but above all it was highly productive. Plant growth was used as a measure of the effectiveness of soil regeneration.

The process to achieve this transformation is simple, the soil must be maintained moist and plants continuously grown. The mechanics behind this transformation is not obvious and only partially understood.

We know that organic material on the surface will be decomposed by the combination of UV light and oxygen, that in aerobic conditions that bacteria will rapidly attack the softer organic material releasing carbon dioxide, that under anaerobic conditions bacteria will release methane and that fungi are more adapt at attacking the harder components particularly the lignin.

Of course bacteria and fungi attack organic material because it is a source of energy. Exactly the same reason that every living creature depends on organic material. This organics material which is devoured for energy provides very little benefit for the soil structure or for averting climate change, simply releasing carbon dioxide and methane back to the atmosphere. Measuring soil carbon may indicate a high level of carbon but much of this will be temporary.

However a certain amount of the organic material will be converted into a substance which is generally referred to by its common name of humus. The critical issue is the amount of carbon which is locked into the soil as stable humus. Despite the apparent lack of a scientific name, or in fact having been the subject of intensive scientific research humus is vital for life on earth.

Humus however has two properties which are of immense importance. Firstly it is stable and will resist decomposition for long periods of time; - some people claim for hundreds of years. This makes it valuable as a means of averting climate change. Secondly is its remarkable effect of soil quality transforming virtually unworkable clay into top grade soil. This is achieved by a process of aggregation in which fine particles are held together in small clumps.

Some people say that this is physical, the long chain molecules simply entwine around individual soil particles while other say it is the result of Van de Waal forces, those secondary forces which occur when molecules are in close contact.

The process of forming humus is of great importance. At the macro level it is clearly a result of microbiological action. Creating beneficial conditions for the appropriate microbiological action has a major influence on the proportion of humus that is formed.

At a micro level it has been suggested that enzymes which fungi release from their hyphae to dissolve mineral particles is involved in the formation of humus.

If I can quote from James Amonette, (Pacific Northwest National Laboratory, Richland, WA.) as an indication of our scientific understanding.

‘While incompletely understood, the humification process by which soil C is stabilized (Stevenson, 1994) is believed to involve several parallel pathways. Of these, the polyphenol formation pathway generally dominates. The rate limiting step for this pathway is believed to be the oxidation of polyphenols to polyquinones, which then polymerize with amino acids to form humic material. This oxidative polymerization reaction is catalyzed by polyphenol oxidase (PPhO) enzymes such as tyrosinase (Martin and Haider, 1969, 1971; Nelson et al., 1979), but soil minerals such as allophane (Kyuma and Kawaguchi, 1964), Fe and Mn oxides (Shindo and Huang, 1984; Stone and Morgan, 1984; McBride 1987), and smectites (Kumada and Kato, 1970; Thompson and Moll, 1973; Filip et al., 1977; Wang et al., 1978) also promote the reaction.’ www.flyash.info/2003/47amon.pdf

While science may not fully understand the process of humification this does not prevent us taking advantage of the process to resolve the great challenges facing humanity. This is relatively simple and easily backed by simple experiments.

The wicking bed process with the moist conditions and recycling of air and water and water can be observed to be highly effective in creating humus. This can be accelerated by the use of fungal initiators or inoculants into the water stream.

One of the major hurdles to adoption of any method of carbon capture is measurement. It can take time for organic material to form stable humus so a common approach has been to measure carbon content over time resulting in farmers having to wait sometimes years to receive payment from carbon trading. This removes a major incentive for farmers to adopt carbon capture.

The wicking beds use organic waste from external source so it is easy to measure the quantity added. Only a small proportion of this organic waste is converted to the stable humus. The ratio of organic waste to humus can be measured in a separate controlled trial by measuring the amount of humus generated from a given quantity of organic waste. This ratio can then be used to predict the amount of humus which will be created, so providing a simple basis for carbon trading.

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Large scale adoption

The object is to create a more sustainable agricultural system. This will only have an impact if applied on a large scale.

The farmer obviously benefits from increased production with lower inputs of nutrients and water and improved soil quality. These are the internal benefits for which the farmers receive revenue. However they receive no financial rewards for the external benefits of reduction in green house gases, mitigating climate change, reduced pollution and providing a convenient way of reprocessing waste materials. The benefits flow to the community at large.

There are costs in setting establishing the wicking beds, this may not be too much of a problem in developed countries with an affluent farming system; however the bulk of the farming community is not affluent and is based in developing countries where up front cash dominates action.

These less affluent farmers need financial assisting to establishing large scale application. Carbon trading, even at moderate price levels would pay for these establishment costs. Money however is only part of the problem; individual farmers are unlikely to have the time or expertise to take advantage of the unfortunately complex process of carbon trading.

Local Governments have the expertise, or at least can readily acquire the expertise. They also have access to machinery which would help the installation of the beds. But they also often have major problems with disposal of organic waste. Often it end up in land fill or is burned, both negatives for climate change. This simply needs slashing to provide filling for the wicking beds.

Local Governments are also responsible for native forests which can provide major fuel for bush fires which will undoubtedly be part of the climate change scene. Controlled burning is often adopted as a solution but this is incredibly wasteful and dangerous. However modern slashing machines can clear forest undergrowth very rapidly providing filling for the wicking beds.

Sewage is also another problem that local Governments have to contend with. Most countries do not accept the use of sewage or sewage water in agriculture for fear of pathogens. However wicking beds can operate on a double pass system. Sewage can be used to irrigate and provide nutrients in separate wicking beds which are used to grow trees which are then pruned to provide filling for the food producing wicking beds.

Fast growing trees can be selected which absorb significant amounts of carbon dioxide. With the appropriate selection they can also ‘mine’ key nutrients like phosphorous and potassium which are then captured in the prunings. This would relieve pressure on the world’s resources which are coming under increasing pressure, particularly phosphorous.

Local Governments are best suited to provide a complete package, collecting revenue from carbon trading for the farmers, providing them with organic material for their wicking beds, together with expertise and may be with the use of machinery.

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The future of food

We have developed a growing system which can cut water use by half and also sequesters significant quantities of carbon into the soil.

Organic material, is integrated into the sub surface soil by selected biological action to form a highly water absorbent sponge like material which provides continuous supply of moisture to the crop growing above.

The system is highly productive; uses much less water and captures significant amounts of atmospheric carbon. This is of global importance as climate change advances and we need to produce food with less and more erratic rainfall.

This system has been widely adopted in Australia by enthusiastic environmentally sensitive growers but now we need to move onto the next stage of gaining wide international adoption.

We are therefore looking for partners to set up joint venture operations nationally and internationally who can provide training for growers adopting the system and supply the biological initiators, and other supplies.

If soil carbon capture were adopted, as it inevitably must, under international carbon trading rules, this would be an extremely profitable operation for growers adopting the system.

As China is the largest and most rapidly growing emitter of atmospheric carbon we are particularly interested in finding a Chinese joint venture partner.

If you are a potential partner, (or know of such a potential partner), please contact me at email colin austin

Introduction to wicking beds

Fore more details see www.waterright.com.au

For many years technologies, such as plant genetics, fertilizers and irrigation, have provided the majority of the world with an abundance of food.

These days of abundance are drawing to a close. Global warming with its more erratic rainfall, loss of soil fertility and structure, reduced land area from increased urbanization and of course the ever increasing population are placing ever increasing pressure on food production which are unlikely to be resolved by the traditional approaches.

We need a total rethink of food production for the future.

What plants need

Plants need water, air and nutrients in a careful balance. One aim of the wicking bed system aims to achieve this balance. Another aim is to store water, particularly after a heavy rainfall for use by the plants later.

There are many variants on the wicking bed system (see www.waterright.com.au) but the simplest is shown here.

trench First a shallow trench about 300mm is formed and the top soil stored for later use. It can be as long as you like but it is convenient to keep the width about 1 to 1.5 meters.

The bottom should not have sharp objects which may puncture the plastic.

plastic liner The trench must be horizontal so the water spread uniformly along the length.

The trench is lined with a plastic sheet and a porous pipe laid in the bottom. The pipe is simply to transport the water along the length of the bed.

base layer organic waste The trench is then filled to ground level with organic waste. Here we are using wood chips any organic waste will do. The more irregular and open the better as this will hold more water.

Carbon can be captured from the atmosphere and will eventually be incorporated into the soil. Weeds or trees like acacias grown on unproductive ground will add nutrients to the soil.

replacing top soil The top soil is then placed back on top so the bed is some 300mm above ground level.

The top soil may be mixed with worm castings, soil conditioners like gypsum and fertilizers like blood and bone.

This layer drained easily and is wetted by wicking action from the layer below.

covering plants Various species of worms are incorporated to maintain the soil conditions.

Seeds or seedling are grown in the normal way but no water is added from above after the initial wetting after sewing or planting.

The surface is dry so there is no loss of water by evaporation.

The reservoir holds a large volume of water. This particular bed 1.5 meters by 5 meters holds some 640 liters so only needs occasional watering. Rainfall can also be directed into the reservoir to make use of heavy rains which would otherwise go to waste.

The bed can be protected by shade cloth or a plastic film to keep off pests and reduce evaporation even further.

For more information go to www.waterright.com.au

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