Soil sustainability

By Dr J Floor Anthoni (2000)
Agricultural land, the land that feeds the world, is in serious difficulty and it is not at all certain that it will be able to produce enough food for the world's population, in perpetuity. Confusion reigns about what sustainability is, but in this chapter we'll define some basic rules that will help people to understand it and to better manage their land. What is energy efficiency on the farm and is it important? Is the economy of farming of influence on sustainability? What can we expect of permaculture and organic farming? Does farm ownership affect sustainability? What difficulties do farmers face compared to other businesses? What can we do towards soil sustainability?
"Farmers, fisherman and hunters are by nature conservationists but today they have been unfairly maligned by a powerful but ignorant urban minority which controls the environmentalist agenda" - Walter Starck, 2005

please note that this document consists of two parts, part1 and part2 (this page)

signs of fatigue

The world's agriculture is showing signs of fatigue. Modern cropping, even with minimal tilling, may not be sustainable.

disrupting the water cycle

By changing the landscape, humans are also invisibly disrupting the water cycle, leading to unexpected droughts and loss of water.

defining sustainability

Our means of food production should not only be maximal when the world's population peaks but more than adequate for thousands of years to come. An enormous confusion reigns about what sustainability entails, but in this chapter we'll boldly define the natural laws that rule it.

sustainable systems

Not all of today's agriculture is in difficulty. This chapter reviews the agricultural systems that have been a failure and those that work sustainably.

energy efficiency

The purpose of food is to feed humans, so that they can spend the energy to live. Food production should be energy-efficient, so that more food energy is obtained than work expended to produce it.


In order to earn its keep, farming must be economic. Income must exceed expenditure. Many improvements have been made as a result of new knowledge in the 'green revolution' and these improvements will continue. But the soil does not need to be compromised.


Often the question of ownership is an important factor in how the land is managed. This chapter looks at a number of issues.

permaculture and organics

The unsustainability of various farming practices has not been left unnoticed and alternative ways are being tried. This chapter discusses two of these.

what can we do?

Soil sustainability is obviously an issue that affects society. So what can society do about it?
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Energy efficiency

In the days when humans were roaming around in family groups, hunting and gathering their food, they would always find more food than needed, so that their energy expenditure was covered. In good times there was more time left for playing and socialising, whereas in the bad times they had to cover larger distances. In really bad times, they would spend more energy in searching than the food provided and people would starve and die.

When farming began, humans discovered that they needed to spend less energy for finding (growing) more food. In those times, all labour was human toil. Communities developed. In really bad times, when it took more energy to farm, than the food contained, communities had to pack up and move on, or die. They often did both. Up until the start of the industrial revolution, humans needed to farm in an energy-efficient way in order to survive, but fossil fuel changed all that. Fossil fuel has been so cheap and convenient that it immediately replaced human labour and draught animals. It was used to transport produce far across the world and to travel far out to sea to catch fish. It is often quoted that the loaf of bread you buy today, cost six times more energy to bring it to the supermarket than you will gain from it as food, and this does not include the solar energy that went into it and the heat needed for baking. The following table gives energy balances for three types of farming the same crop of corn. It shows that the energy efficiency of cropping has eroded because of the use of fossil fuel, but the energy efficiency of human labour improved dramatically.

Material and energy inputs and outputs per hectare for corn production
Mexico, human labour
ins & outs quantity kcal
labour h
axe & hoe kcal
seeds kg
yield DM kg
out/in ratio
1944 10,683,820
Mexico, using oxen
ins & outs quantity kcal
labour h
ox hours h
ox food kg
ox hay kg 
machinery kcal
seeds kg


yield DM kg
out/in ratio
1944 10,683,820
USA, conventional corn production
ins & outs quantity Mcal
labour h
machinery kg
fuel l
Nitrogen kg
Phosphorus kg
K potash kg
Ca lime kg
corn seeds kg
insecticides kg
herbicides kg
electricity Mcal
transport kg
Yield grain DM kg
out/in ratio
6500 26,000
Source: Pimentel and assoc.  Note that these estimates are subject to large variations from place to place.

The basic idea behind farming is that we harvest the energy from the sun to feed ourselves. The sun's energy is free but we have to do some work to obtain the fruits of our labour. For human labour farming (left column), the gain in energy from the crops was nearly 13 times the energy put in. Using draught animals (middle column), this reduced to 6.3 but four times less labour was needed. In modern farming the grain provides only three times the amount of energy that was expended from fossil fuel but labour was another 7 times less. The energy 'subsidy' in this case is 30%. We don't realise how much our various foods are 'subsidised' by fossil fuel energy like in the third column above. The table below shows the magnitude of energy subsidies for various food crops. Those exceeding 20% should give cause for concern.

Energy subsidies for various food crops
energy food crop energy
protein food crop energy
Hunting and gathering
Wet rice padis
Intensive rice (USA, Japan)
Intensive wheat, USA
Low intensity corn
Potatoes, peanuts, soy beans
Ranging cattle
Low-intensity eggs
Milk from grass-fed cows
Coastal fishing
Grass-fed beef, intensive eggs
Feedlot beef, distant fishing
Source: J S Steinhart: Energy use in the US food system, Science 184, April 19, 1974

What the table shows is that energy foods are still energy-efficient but protein foods are marginally so. Humans have always valued protein foods higher than grains and beans and didn't mind spending more energy to obtain these.

Please note that in none of the calculations and measurements of energy efficiency, account is taken of down-slope effects, the cost of polluting soil, rivers and the ocean. If energy were to be used to clean these up, all world cropping would indeed turn out to be both energy inefficient and uneconomic!

If farming were to supply all energy needs for humans, which could be the situation when all fossil fuels have run out, while nuclear power remains unacceptable, then the amount of soil needed would require two more world planets at today's population levels and consumption rates. By the time Earth's population stabilises, another 4 worlds would be needed! This illustrates humans' dependence on fossil fuel. The human 'ecological footprint', the amount of land needed to sustain one person, is estimated at 4.3 ha/person (at Canada's living standard) but only 1.5 ha of productive land are available per person, if the world is shared fairly. The following table may illustrate that the world is not shared fairly at present (Source: M Wackernagel, Our ecological footprint. 1998.):

consumption per capita, 1991 Canada USA India World
CO2 emission t/yr
purchasing power (US$)
vehicles per 100 persons
paper consumption kg/yr
fossil energy use GJ/yr
fresh water use m3/yr
ecological footprint ha/person 4.3 5.1 0.4 1.8

A human footprint would typically allocate 55% for energy cropping, 5% for roading and housing, 15% for food cropping, 11% for pasture, 14% for forest products.



For farming to survive, it must be economic. Income must exceed costs. Farming is a business that needs to make a profit, including a living for the farmer's family. If income does not meet costs, farmers can survive only by taking shortcuts on expenditure such as deferring the application of fertiliser and postponing maintenance and by living frugally, but eventually these savings affect productivity and income. It is a downward spiral that includes deterioration of the land, which affects society. It is thus important that farming remains profitable.

Let's look at the major improvements that have been made to farming in the past 100 years (and some concerns). Each point needs more discussion but it is assumed that the reader is familiar with the issues.

Progress in farming has been so enormous that farming profits must now reach astronomical heights. But they don't. Farmers everywhere are still teetering on the brink of the narrow margin between profit and loss, risking their soils in the process. Why?

It is caused by competition in a freemarket economic system. Farmers compete in an open market where demand and supply govern prices (theoretically). In case of shortage, prices go up and reversely, in case of overproduction, prices slump. Through economic oscillations, farmers will eventually produce precisely what is demanded, no more, no less. The market stabilises.
The freemarket system exerts a relentless pressure to produce more efficiently, to make more with less. Much of the world's progress in trade and industry is driven by this freemarket 'invisible hand' which makes people produce what others want, not by decree or planning or foresight, but by the simple desire to make money. It is an excellent system of delivering the cheapest product to the most people. But it has a number of serious shortcomings, which will be treated in a separate section on this web site.

Farmers face a number of freemarket pitfalls:

The reason of discussing the economic reality surrounding farming is to show that the problem of overexploitation cannot be solved on the land alone. Other measures must be taken to relieve the economic drive for overexploitation.
Although subjected to relentless market pressure, farmers have somehow been spared the ravages of the global economy:



Land ownership is another issue relating to soil sustainability. Land is a very strange article, compared to all others we know. It cannot be transported or shifted. It has no life span, because in thousands of years it will still be there. It can be passed from generation to generation without necessarily wearing out. It can increase in value, rather than wearing out like a car does. It produces from the rain and sun, without the need of putting anything in. It is the substance that a nation identifies with and calls it 'home', for what would be left of a nation if all its land was owned by overseas interests? 

Most of the land is privately owned, although in some countries it is owned by the Government or by the nobility, who lease it out. In some places, the land is shared as a commons, without an owner. These three forms of ownership do make a difference to how the land is managed.

All farmers should be aware that they are really borrowing the land from their children. We all die but the land remains. In our short existence on Earth, we should take care of our lands such that we can give it to our children in a better state. It is obvious that society at large should be interested in these matters and that some government controls and assistance are necessary.


Permaculture and organic farming

The movement towards sustainable farming is spearheaded by those proclaiming permaculture, meaning permanent culture. The life span of productive soil must not be measured in centuries or even millennia; it must be forever. Australian Bill Mollison formulated the ideas behind permaculture in 1975.
Permaculture strives for agriculture that is ecologically sound and sustainable in the long term. This means that it should be non-polluting, economically and socially viable, and provide for its own needs. Permaculture uses the natural qualities of plants and animals, combined with the natural characteristics of landscapes and structures, to produce a life-supporting system for city and country, using the smallest area possible. Permaculture is essentially a way of achieving efficient and sustainable food production. The sustainability of our culture is fundamentally dependent on our relationship to the land.
Permaculturalists essentially wish to turn the clock back a little and pay more attention to nutrient cycling. They really like the health of soil to be more important than profits. They like to bring into practice what this section on soil is all about, but they have to compete with those farmers who don't. In the end, short-term success is dictated in the freemarket by price. So they need a little help.
The help these farmers need, is just to break the dictates of the freemarket system, where only price rules. It is a trap that many good farmers wish to escape from. Somehow the fact that the environment and the land are better off, needs to be appreciated. Here are some ideas: Perhaps unfortunately, the followers of permaculture focus on small-scale intensive systems of self-sufficiency, supporting alternative lifestyles (private productive ecosystems in which to live). They talk about extremely diversified farmlets or gardens with both plants and animals that work together, about edible gardens, about ponds with multiple functions. Such farmlets are very labour-intensive, but when properly planned and designed to 'let nature do it', the toil can become less. Nutrient cycling, water harvesting and wind power generation assure that such farms do not depend on fossil fuel and can last forever.
Please note that the inability of recycling wastes because produce is transported far away, is not addressed.

Organic farming
The practices of organic farming are based on the ideas behind permaculture, enforced by a strong belief that everything 'chemical' is therefore bad for human health and the environment. Organic farming therefore shuns both synthetic fertilisers and biocides. It also bans food irradiation and genetic modification. Organic produce is sold to a growing population of health-conscious people who share this belief. They are also prepared to pay a much higher price and don't mind a few natural 'freckles' on organic fruits. This makes an enormous difference to the amount of chemical pest control needed. In fact, organic farms use only 'natural' biocides. The organics movement is well organised and organic farms are not only certified, but also verified regularly. One could say that the viability of organics begins with the buyer.

However, there are problems with any system that is based on beliefs rather than knowledge, reason and logic. To claim that a chemical substance made naturally differs from one made synthetically, is just absurd. Plants certainly do not make this distinction [1]. But to minimise the use of pesticides and herbicides is commendable. In the chapter on economy, we've shown the many improvements that happened to farming because of science and technology, and organic farming benefits equally from these (is not chemical), being able to produce more from less land. Organic farmers also see no harm in using copious amounts of fossil fuel (is not chemical), like other farmers do, and they do not mind ploughing the land either (is not chemical).

Where organic farming fails to feed the world, is summarised here:

Organic farming is probably here to stay, supported by its devotees of health culture ('You are what you eat'), but won't be a panacea (cure-all, universal remedy) for feeding the world. Read more about organics in the USA's National Organic Programme www.ams.usda.gov/nop/

[1] Note that many confuse the taste of organic produce for their quality. Modern cropping, particularly in glasshouses creates an environment in which plants can grow excessively, resulting in bland tasting produce. Had such vegetables been produced in the open, they would have grown more slowly while accumulating more 'taste'. But this has nothing to do with either sustainability or organics.


What can we do?

From the previous chapters, we have learnt that soil is not only an indispensable substance for the survival of mankind, but also that we are losing it rapidly. This is not a new phenomenon, as in past history it simply caused civilisations to collapse, not because nobody saw it coming, but because nobody was able to do something about it. Today's civilisation, with all its scientific knowledge, appears to have landed in the same predicament. So, what can we do? 

The problem is not new, and everywhere in the world people are trying to do something about it. The problem is not small either, since it effectively concerns all soil modified by humans. There are no standard solutions, since every type of soil and every climate and every way of using it, creates vastly different circumstances. How then can we pretend to offer the solution to all problems? Well, we can't. But somehow people have underestimated the importance of cycling and retaining nutrients, mainly because of underestimating the importance of the soil biota. Here is where soil fertility is made and retained. If farmers become more aware that they are farming soil, rather than produce, we may head in the right direction. But there are many areas where helpful improvements can be made.

The following actions may help to improve sustainability:

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