DEFEAT THE DESERTS

Contra-desertification projects by Terence Westgate & Associates

BACKGROUND

Some facts about population, nutrition, soil, and water

1. The human population is growing and must be fed and watered. Of a world population of 7.3 billions, one person in every nine is suffering severe malnutrition or starvation.

2. Human nutrition is part of the carbon, nitrogen, hydrogen and oxygen cycle fuelled by energy from the sun and enabled by plant life.

3. Atoms are eternal – molecules may re-arranged to form different compounds, but they last forever and are not destroyed, so food and water is re-cycled as long as there are consumable plants and fertile soil and water to sustain them

4. The distribution of fertile soils and fresh water, and the density of the population is uneven. To create a sustainable balance, three things are required; (1) a reduction in population growth, (2) rehabilitation of eroded soil, (3) recycling water.

At Terence Westgate & Associates we recognize these facts and apply our expertise and experience to plan, cost and justify soil and water conservation projects

What is ‘Desertification’?

The UN definition of desertification is

‘Desertification is a type of land degradation in which a relatively dry area of land becomes increasingly arid, typically losing its bodies of water as well as vegetation and wildlife. It is caused by a variety of factors, such as through climate change and through the overexploitation of soil through humankind's undertaking.

Or in other words, ‘soil erosion’.

How serious a problem is soil erosion.

“Generating three centimeters of top soil takes 1,000 years, and if current rates of degradation continue all of the world's top soil could be gone within the next 60 years. About a third of the world's soil has already been degraded,” Maria-Helena Semedo of the UN Food and Agriculture Organization (FAO) told a forum marking World Soil Day 2016.

A Study at Cornell University (Journal of the Environment, Development and Sustainability, Vol.8 2006) led by David Pimentel, reported that:

“Around the world, soil is being swept and washed away 10 to 40 times faster than it is being replenished, destroying cropland the size of Indiana every year. Yet the need for food and other agricultural products continues to soar. Soil erosion is second only to population growth as the biggest environmental problem the world faces. Yet the problem, which is growing ever more critical, is being ignored, because who gets excited about dirt?”

Put another way, the human population is growing and must be fed and watered, but out of an estimated world population of 7.3 billions, one person in every nine – that’s 800 million men, women and children are suffering severe malnutrition or starvation.

Every year the deserts get bigger and bigger and the unsustainable population grows.

That’s the most serious problem on the planet.

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What is ‘Contra-desertification’?

Contra-desertification is a reversal of soil erosion.

First of all, what do we mean by soil? Specifically, we are referring to ‘topsoil’. This is the layer, as its name implies, that is the top layer of soil and is defined by its composition of organic matter, which in turn is comprised of decayed organic material – mainly dead plants. Depth of topsoil for growing – say wheat, will be a minimum of 25 cm, but preferably 45 cm.

Topsoil is, however, a complex substance and is fragile, water will drain through it gently, thus providing ideal conditions for plant growth. Its light density also means that it dries out quickly without a covering of plants, and if exposed to wind, may actually blow away. The opposite also applies and heavy rain can wash away surface layers, eventually reducing the depth to below that required for growing crops – soil erosion.

Topsoil also harbours Mycorrhizal fungi which the Royal Horticultural Society describes as:

‘Mycorrhizas are beneficial fungi growing in association with plant roots, and exist by taking sugars from plants ‘in exchange’ for moisture and nutrients gathered from the soil by the fungal strands. The mycorrhizas greatly increase the absorptive area of a plant, acting as extensions to the root system.

Neither fungi nor plants could survive in many uncultivated situations without this mutually beneficial arrangement. Mycorrhizas also seem to confer protection against root diseases.’

What are contra-desertification processes?

To transform eroded land into fertile land and then protect the land against further erosion, the following functions are required:

Replace eroded topsoil with compatible organic matter – compost.

Provide shelter from wind.

Irrigate.

Once the topsoil has been restored it will, of course, be necessary to maintain healthy topsoil to grow food producing crops.

Compost

Compost is organic matter – the essence of topsoil, which is produced by decomposing organic materials under controlled conditions. There are two methods, ‘anaerobic’ in which the organic materials are digested in water in sealed containers to produce methane gas, used as a combustible fuel and the remaining sludge composted to produce fertilizer.

The second method is ‘aerobic’ composting in which the organic material is kept aerated and the resulting organic matter applied directly to the soil.

In both cases, the raw material should be shredded before processing, and it is bacteria that perform the actual transformation of the material into organic matter – or compost. Typical examples of raw materials for composting include food waste digested and undigested, straw, paper etc., to create a carbon:nitrogen ratio of approximately 30:1.

The composting process means that as well as replacing the substance of eroded topsoil, the compost contains organic fertilizer comprising nitrogen, phosphorous and potassium.

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Shelter from wind

Topsoil erosion by the wind can be reduced by planting hedges, planting ground covering plants and not ploughing the soil.

Shelter from water

‘Water tends to find its own level.’ Rainfall in excess of what soil can hold or drain, will produce flooding, which in turn will wash away topsoil. Precautions include land drainage and terracing.

Irrigation

Water is an essential component of healthy fertile soil. Water is, however, a precious commodity and simply spraying water onto the surface of the soil will lose more to evaporation than will reach plant roots. Efficient irrigation methods include root level drip-feed systems in conjunction with surface covering plants.

In areas of water shortages, water for irrigation may be recovered from wastewater treatment plants after membrane filtration. This same method may be used to create non-potable (but safe) recycled water systems in towns and cities to make more water available for irrigation.

Costs and benefits of contra-desertification measures

Each contra-desertification project will have its own costs – labour, equipment and opportunity costs – in terms of what alternatives the resources could be used for.

Where a region is suffering, or is vulnerable to desertification, there is a diminishing range of options. The land must be nurtured and sustainable food production maintained.

Justifying choices becomes a matter of education and political communications as much as it is soil science and biological processes.

How can we help?

At Terence Westgate & Associates we take a multi-disciplinary approach and build a specialist team for each project including agronomists, water engineers and financial experts.

A typical project consists of the following stages:

Agreeing the project objectives with the client

Determining resource requirements

Assessing costs, timescales and availabilities

Building a cost-benefit model to decide feasibilities of the project

Introducing finance for the project if required

Managing the project

Reporting to the client

Contact Terence Westgate: terencewestgate@gmail.com SMS +44(0) 7903 042 778

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