1Y11 Geography

Managing the effects of soil erosion Managing the effects of soil erosion and desertificationand desertification

2

Recall that soil erosion is one of the Recall that soil erosion is one of the main drivers of desertificationmain drivers of desertification

• So any way that reduces soil erosion and it effects, can also help prevent and mitigate* desertification.

• Main ways to do this are: To reduce the ability of rain water to erode the soil To reduce the ability of the wind to remove the soil To increase the health of the soil by adding organic

matter, which also reduces the ability of the wind to erode

* Moderate or counteract the force of the impact

3

The Sahel is a semi-arid to arid area of scrubland and desert stretching mainly across the countries of Ethiopia, Eritrea, Djibouti, Northern Nigeria and Somalia. Desertification in the Sahel is progressing at a disturbing rate affecting 2,500 hectares each year.

The reasons for desertification in the Sahel are:

• Human - Large population increases in recent years – has lead to overgrazing of the land to meet higher food requirement. The increased energy requirements have lead to deforestation as more firewood has been needed. Environmentally unsound policies that do not forbid or actively encourage activities that may lead to desertification. Lack of education in agricultural policies and techniques has lead to stripping the land of minerals and humus which has not been replaced. Poor irrigation practices raise salinity, and sometimes dry the rivers that feed large lakes: the Aral Sea and Lake Chad have shrunk dramatically in this way. •Environmental or physical factors - Long periods of drought and short periods of torrential rain experienced by the Sahel region, and some climatic change.

4

The Tanout area, situated just south of the Sahara desert, is one of the driest inhabited places on earth.

The Eden Foundation was set up in 1987 in Dalli, Nigeria. It helps 2,500 families in 123 villages. The Eden Foundation helps farmers stop desertification whilst at the same time increasing their yield. Eden’s solution is to bring them trees and bushes that can grow naturally in this dry area and give food, even in times of need.The Solution: Plant edible perennials among their crops. These stabilise the soil, holding it together and so preventing erosion by the rains. They also shelter the crops and the soil from the wind, further preventing erosion and increasing the yield. One farmer in Dalli with shielded crops produced 130 baskets of millet, which was 3 times as much as his neighbour whose crops were not shielded. The perennials often have extensive root systems, which are encouraged to extend even further by the method of planting them by direct seeding, so planting them directly into the dry earth. This means that they will grow slowly but be hardier as they will have even more spreading root systems than normal. The perennials chosen are mostly local shrubs or trees such as the Ziziphus bush. These trees produce fruit once mature which are sold or eaten by the family. In 1998 the fruit produced per family of the Eden Foundation was worth, on average, about Euros 2, by 2007 this had increased to Euros 74

Unprotected field destroyed by wind and erosion

Crops protected from tree planting

Increased yield and profitBy Craig

5

• Edens solution to this is handing out free seeds that have been researched at their local field station.

• They use direct seeding. This means when you plant a tree directly in the ground, without watering it, it will still be able to grow, even if the process is quite slow.

• These trees and bushes can grow naturally, without irrigation or chemical fertilizers.

• The farmers go to them of their own accord, and can order the seeds they want for free. They then show them how to direct seed, and offer any advice needed.

Since 1991, Eden have helped over 2600 households in 134 different villages. The tree’s given produce fruit that can either be eaten or sold.

"Thanks to our Eden trees, we've had food to eat even though the millet failed. For the last three years, we haven't had a single good rain in our village and this year's harvest lasted less than a month. Instead, my family has lived from the Eden fruits on our field which gives us food for the day. We depend on it, for there is nothing else to eat around here.“ - Musa Abari from Garin Farara

By Rebecca

6

Contour stone bunds trap organic material such as

leaves, whilst allowing water to trickle through. This distributes water evenly over fields when it rains, and the trapped organic material can be raked across the fields, eventually turning to humus and so improving the quality of the soil. 10,000 people in more than 500 villages in Mali have been taught this technique, in these villages, collectively, contour stone bunds have been used on more than 10,000 hectares of land.

UNDP United Nations Dry lands Project - Sahel

Sustainable planting and irrigation techniques

Barriers to stop wind erosion of soil

education

By Craig

7

By RosalieThe name for these stone walls are bunds

8

Digues Filtrantes• Permeable rock dams (digues filtrantes). The structures are

typically long, low dams of loose stone constructed in gullies and across valleys. Because they lack a spillway, the dams force flood water to spread over their length, which strongly reduces its erosive force. They also force water to infiltrate: this results in large quantities of sediment being deposited, often filling up gullies within two years – which in turn creates favourable conditions for growing crops where nothing could be grown before.

By Thomas

9

Contour Bunding, Burkina Faso

-In the 1980s, British Oxfam worker Bill Hereford suggested contour bunding as a way of combatting desertification in Burkina Faso.

Contour bunding is the process by which lines of stones are placed on slopes and contours to stop topsoil washing away and help rainwater settle in.By Zoe

10

Contour bonding is an inexpensive and simple solution for African farmers.

- Farmers self manage the process.

One disadvantage of contour bunding is that it has resulted in a lack of stones. By Zoe

11

- Over 400 villages have participated in using contour bunding.

- The number of hectares of land reclaimed bunded has risen from 50 in 1982-83 to 8 000 in 1989 and it is estimated that thousands more hectares of land has been bunded since.

- In Burkina Faso, it has increased the awareness of careful land planning ,care of the environment and overall sustainability.

By Zoe

12

Terracing

• Prevents rain fall from washing away top soil and nutrients.• Cheap to build, only man power needed.

By Thomas

13

Terracing technology in DarfurPositive Action

• Practical Action suggested a one-year demonstration farm showing the use of crescent-shaped terraces in comparison with traditional terraces. All the necessary equipment and tools were produced locally and volunteer farmers (men and women) were trained in how to lay out and construct the crescent-shaped terrace.

• Household crescent-shaped terrace catchments cover an area of 0.5 hectares, 100-150m in length, with earth embankments of 0.75-1m high, and ditching laid in the back of the terrace of 0.5m deep by 1m wide.

• Twenty-five pioneer farmers in Azagarfa supported the demonstration by building crescent- terraces for comparison with their traditional terraces. These were outside the ITDGPractical Action farm, and built with the farmer's own time and money - risky for them if the project failed. However, early in the rainy season results were already showing. ITDGPractical Action observed that 20 terraces were changed to crescents, as other farmers adopted the new technology, even before the demonstration was complete.

Practical Action

Crescent shaped terraces

By Thomas

14

ResultsTraditional terraces Crescent-shaped terracesWeak rectangular shape subjected to flood washing, no drainage system

Stronger crescent structure resists flood washing, drainage system allows run off water

Square shape can't follow land contours Crescent shape follows land contours

Flood washing increases soil erosion and reduces potential for water retention

Tolerance of flood washing avoids soil erosion and increases water retention

Crops can't survive over 10 days without rain Crops can survive over 21 days without rain

No ditch Ditch provides water for household use and for animals for two months

Low yield Higher yield (double the traditional yield)

Potential to harvest crops for 6 weeks Potential to harvest crops for 12 weeks

Need regular maintenance Maintenance not required

Crop stalks died after harvestingCrops survive, shooting at the first shower of the next rainy season and giving early harvest in time to get higher market prices

Complete rebuilding required for next rainy season, including costs of hired labour

Next rainy season requires maintenance only - minimal labour required

Minimum of three showers can give harvest Just one shower can give harvest

By Thomas

15

Planting Trees

• Roots bind the soil together and leaves provide shade and intercept water.

• Cheap and long term solution.• Provides fuel, wood and building materials.

By Thomas

16

The Great Green Wall • Imagine a green wall – 15km wide, and up to 8,000km long – a living green

wall of trees and bushes, full of birds and other animals. Imagine it just south of the Sahara, from Djibouti in the Horn of Africa in the east, all the way across the continent to Dakar, Senegal, in the west.

• The building of this pan-African Great Green Wall (GGW) was approved by an international summit in Bonn, to combat desertification (UNCCD).

• The GGW, as conceived by the 11 countries located along the southern border of the Sahara, and their international partners, is aimed at limiting the desertification of the Sahel zone.

• It will also be a catalyst for a multifaceted international economic and environmental programme.

By Thomas

17

Great Green Wall

-In February 2011, the UNCCD (United Nations Convention to Combat Desertification) approved the planning of a “Great Green Wall”

-The idea was initially thought of in the 1980s by Burkina Faso’s president Thomas Sankara.

-The ”Great Green Wall” will consist of trees, birds and animals.

By Zoe

18

The Great Green Wall is planned to be a continuous green band - 8,000km long and 15km wide. It will stretch from Dakar in the East to Djibouti in the West.

-It will be rerouted around mountains and rocky areas.

By Zoe

19

The aim is to limit desertification by planting vegetation.

- By doing this, it is hoped it will act as a catalyst for both environmental and economic activity.

- It should help preserve water supplies especially in Lake Chad and provide fruit and vegetables.

It is hoped it will help political stability of the countries in the Sahel region and reduce poverty.

By Zoe

20

• The Great Green Wall is a project developed by the African Union to face desertification in South Sahara. It is the largest environmental transformation in Africa and the green belt of trees expands out 7,775km long and 15km thick.

The trees' shade and bulk help offer crops relief from the overwhelming heat and gusting winds.

The Great Green Wall

Constructed along the Sahel belt.

Spans out across 11 countries of Africa

By Loy

21

The aim behind the Great Green Wall is to limit desertification by planting all sorts of vegetation. Although it does mostly consist of trees, there are some animals that inhabit the Great Green Wall.

The Great Green Wall aids in both environmental health and helps farmers economically.

By Loy

22

Sahel - MaliWhat is its living state?Mali is one of the poorest countries in the world: 70% of its population lives on

less than $1 per day. Its population amounts to about 13 million. Due to where the country is situated, semi-desert and desert are common. This means that 80% of the countries population depend on rain-fed agriculture, livestock and fishing to maintain there poor state of living. The degradation of fertile soil, makes this increasingly difficult to do.

What is being done to help Mali deal with soil degradation?One company that is trying to help is Sahel Eco. It is a non-profit making

organisation, that helps Mali to change the way they farm and cultivate crops, just in sandy, infertile soil. They support the local community by training and building. This teaches the people, to better manage and maintain the natural resources on which they depend. Along with this Sahel eco works along with governments and Research Institutes to get the best possible out come for the community.

By Alesha

23

What is the purpose of this project?The purpose of this project is to increase the numbers of trees on agricultural land and by

doing so, to reversing the effects of desertification on rural and urban livelihoods in Mali. Sahel Eco do this by promoting the adoption of tree managements that are simple and low cost. This can quickly allow for quick re-forestation and benefit many of the community.

What problem does it address?Desertification is one of the primary causes of poverty and under development in Africa.

The constant cutting down of trees, for fuel and basic timbre leaves the fragile soil exposed to water and wind erosion – which are common in the farming season. In extreme cases, the fertile top soil can be completely stripped away. But trees not only help farmer to protect soils and improve crop production, they also provide them with timber, fuel, fodder, fruits, drinks, herbal medicines and raw materials for weaving a variety of useful items including mats, baskets and hats. Restoring the tree cover on village lands and ensuring that the trees are managed in a sustainable way can thus make a major contribution to addressing the interlinked issues of desertification and poverty in the Sahel.

By Alesha

24

By Alesha

25

By Rebekah

26

• In the Sahel, there's a wide range of different ideas being put into action to stop desertification. One would be, the team of people named 'Naam' are travelling Africa planting trees and all sorts of plants. They are also testing new farming methods and trying to bring down poverty. Not only Naam, but lots of other everyday people are planting trees too, to help encourage a healthy landscape.

• The Sahel, life is being brought back to the sands.

By Cameron

27

By Rebekah

28

By Rebekah

29

By Rebekah

30

Using Pearl Millet in Northern NigeriaPearl Millet is a breed of crop seed that is much more drought tolerant and has a little earlier maturity. It also tolerates low soil pH better than sorghum. This aids in managing and combating desertification in Sahel in many ways.

Pearl Millet helps increase the average crop yield for farmers in Sahel. There are also few other breeds of crop seed that have similar features as Pearl Millet. See on next slide.

Here are 4 other crops that are like Pearl Millet. These crops are drought resistant, climate change-ready crops.

By Loy

31

Desertification in Indiahttp://www.caritas.org/activities/climate_change/desertification_in_india.ht

ml

• Half the land in India is now desertified due to overgrazing, shifting cultivation without enough recovery time, industrial and mining activities, unsustainable water management etc…

• This is a big problem, because even though India is only 2.4% of the worlds land area, it supports 16.7% of the worlds population and 18% of its livestock.

• To help this situation, parts of India use the ‘ridge and furrow’ system in the black soil areas. This will help reduce the problem of water logging.

• The furrows are small parallel channels, made to carry water to irrigate the crop, which are usually planted in the ridges.

(This slide is pretty rubbish, but I thought id keep it in just so you could see lol!My other desertification solution is on the next slide )

By Rebecca

32

Desertification in China• Desertification in China is mostly due to over planting, overplowing

and overgrazing; overgrazing – In inner Mongolia the livestock increased from 2 million

(1977) to 18 million (2000). This stripped the land of vegetation, allowing the wind to then blow off the top soil, turning one third of the grasslands into desert. If something isn’t done, it will all be desert by 2020.

• China is very keen to get rid of desertification, with many different solutions.

• For the overgrazing problem, fences have been put up and herders are encouraged to take good care of the land. The government have asked them to cut their flocks by 40%, but the herders aren’t too happy with this.

• They are planting a line of trees and shrub across from the great wall of China to protect farmland. This will eventually cover 4,000 miles in length.

• The Chinese government has encouraged the planting of drought resistant trees such as pines and poplars. In some places the farmers are paid to plant them!

• Migration is huge in china due to desertification. Millions of people have to abandon unproductive land with sand drifting their way.

By Rebecca

33

• In China, they are doing the same. Its difficult to rejuvenate lavish lands, however with enough effort, money and time it is possible. Planting is a very simple and effective way of wiping the deserts clean, thus making it most popular. In any desertification, people tend to adopt the same methods as it isn't an easy challenge, nor is there many ideas.

By Cameron

34

By Rosalie

35

By Rosalie

36

Combating desertification in the Combating desertification in the UAEUAE

UAE

Sahel

By Craig

37

The problemThe UAE lies across the Tropic of Cancer, it is one of the hottest areas of the world. Desertification and salinity of soil is threatening local farms and is destroying the natural habitat of local species. The meagre volume of rainfall the Emirate receives annually is not enough to meet the excessive and growing demands.

A SolutionGreening the desert: Greening The Desert is concerned with converting the natural desert environment into productive agricultural land, conserving its biodiversity and increasing its economic outcome. The UAE efforts in Greening the Desert increased the agricultural area from only 2.4% of the land area in the UAE to 6.5% of cultivated land by the year 2000. As of 2005, 330,000 ha area has been planted through afforestation project in Abu Dhabi Emirate to reduce sand movement and to enhance the environmental quality. Additionally, the government allocated funds to monitor the shortage and imbalance of the underground water that will help in future planning of agricultural activities.

Trials carried out in Abu Dhabi, have demonstrated the potential of biodegradable 'Eco-Flakes' to retain water, promote plant growth and potentially help in 'greening' the desert. The flakes, which are based on a polymer of urea, are 100% biodegradable and are manufactured to different pore sizes depending on the final use of the product. In dry soils, for example, smaller pores are required for optimal water absorption and retention.

After 20 days the plants which were grown with Eco-Flakes were 100% tallerBy Craig

38By Craig

39

Hydrophobic SandWaterproof nanotechnology sand to help green the desert. Emirati engineer Fahd Mohammad Saeed Hareb peers into a bubble of water atop a tiny pile of sand cupped in his hands. Amazingly, the water bubble does not drain through the sand – it remains intact, jiggling like crystal clear Jelly. This is waterproof sand – or as German scientist Helmut F. Schulze calls it – hydrophobic sand, a nanotechnology wonder seven years in the making. Another way to green the desert and beat back shifting dunes of desertification. With new hydrophobic sand in place, traditional watering of desert plants five or six times a day can be reduced to one watering, saving 75 per cent more water, a precious resource that is dwindling across the Arab Peninsula.

By Craig