Lmy10 p geu7a.3 manage may11pp


Published on

  • Be the first to comment

  • Be the first to like this

No Downloads
Total views
On SlideShare
From Embeds
Number of Embeds
Embeds 0
No embeds

No notes for slide

Lmy10 p geu7a.3 manage may11pp

  1. 1. Introduction to managing desertification and soil erosion
  2. 2. What are the issues? <ul><li>As we have seen soil erosion often goes hand in hand with desertification </li></ul><ul><li>So by tackling one you can effect the other. </li></ul><ul><li>Soil erosion can occur due to water in the form of sheets and gulleys and also the wind, and can be made worse by human activity. </li></ul><ul><li>Desertification can occur where there is soil erosion and the rainfall is variable. </li></ul><ul><li>If you can reduce the erosion, the soil structure and quality can be maintained and so desertification is less likely to occur. </li></ul>
  3. 3. So what are the ways of tackling these joint problems? <ul><li>Soil erosion by water is more likely to happen if the rainfall is very heavy, particularly after a drought, </li></ul><ul><li>But if the ground has structures in place to reduce run-off, the erosion will be far less damaging </li></ul><ul><li>There are 2 main routes to achieve this: </li></ul><ul><ul><li>Have perennial plants – trees and shrubs – which will help hold the soil down, and act as a barricade to catch the soil that is being washed away. </li></ul></ul><ul><ul><li>Have a barrier to catch the water as it flows down the slope carrying the soil. </li></ul></ul><ul><ul><li>Keeping ground cover at all times to prevent the water washing the soil away </li></ul></ul>
  4. 4. So what are the ways of tackling these joint problems? <ul><li>Wind erosion occurs after a prolonged drought, when there is little remaining root structure to hold the soil in place and not much organic matter in the soil to act as a sponge to any residual moisture </li></ul><ul><li>The solutions are similar to prevent erosion by water: </li></ul><ul><ul><li>Have perennial plants – trees and shrubs – which will help hold the soil down, and prevent the wind whipping it away. </li></ul></ul><ul><ul><li>Improving the ability of the soil to retain moisture so it less easily blown away by measures including adding organic matter </li></ul></ul>
  5. 5. So many of the solutions will be variations and combinations of <ul><ul><li>Planting trees and shrubs </li></ul></ul><ul><ul><li>Adding barriers to reduce erosion </li></ul></ul><ul><ul><li>Retaining the water in times of heavy rain </li></ul></ul><ul><ul><li>Adding organic matter to the soil, so that it can retain water and provide plant nutrients </li></ul></ul><ul><ul><li>Not leaving the soil as bare ground at any time </li></ul></ul><ul><li>There are specific ways in which these ideas are implemented that vary from place to place and are adapted to the particular circumstances. It is these examples we are looking for. </li></ul>
  6. 6. Desertification and management of soil erosion By Muhammad Hamza
  7. 7. Sahel Region - Where is it <ul><li>The Sahel region is located on the southern edge of Sahara desert </li></ul><ul><li>It also lies across these 10 countries, Nigeria Sudan, Senegal, Mauritania, Mali, Burkina Faso, Niger, and Chad (Ethiopia and Somalia are sometimes included in the Sahel region) </li></ul><ul><li>The Sahel region is transitional between the Sahara desert and the more tropical central Africa. </li></ul>
  8. 8. Sahel Region – What is it like <ul><li>The picture on the left is an example of dry season in the Sahel region, the land is dry and has a few trees due to no rainfall </li></ul><ul><li>However the picture on the right seems lively due to sufficient rainfall and is an example of rainy season </li></ul><ul><li>The Sahel is covered with dust, grass and stunted trees </li></ul><ul><li>This region experiences strong year to year variations of climate </li></ul>
  9. 9. Sahel Region – What is happening <ul><li>The cause of Desertification is a result of the lack of rainfall. Some of the causes are due to the climate change and the oceanic circulation. </li></ul><ul><li>Land degradation occurs because of erosion. This prevents residents’ harvests to grow, therefore this problem forces them to move to new land. </li></ul><ul><li>To make new land home there must be clearance of vegetation and other livestock </li></ul><ul><li>Another problem flooding, which occurs from high amount of rainfall which can erode soil. </li></ul><ul><li>Soil being trampled on by cattle can lose its stability ,moisture and support to the plant. </li></ul><ul><li>Most of the time, desertification affects LIC countries therefore they are less equipped to solve this problem. </li></ul><ul><li>Another problem is that cash crops are grown more than crops to feed people. Cash crops are grown more because they are sold to foreign countries. </li></ul>
  10. 10. Sahel Region – how to prevent it <ul><li>To prevent desertification, awareness is very important. Farmers are not aware of the damage they are causing. </li></ul><ul><li>Deforestation- is the re-plantation of tress. Planting grasses can stabilize the soil and can help cut down on erosion by wind and rain. </li></ul><ul><li>Overgrazing- is important because young tress in the growing process should be fenced off from animals. Also terracing the land is good for the plants because, water runs of the slope and into the area where the plants are safe from flooding water. </li></ul><ul><li>Cash crops should be planted less and crops that feed families should be planted more. </li></ul><ul><li>Good farming techniques should be used to grow crops because, if crops are not treated properly they will erode and will be blown away by wind or water. </li></ul>
  11. 11. India – where is it <ul><li>India is a country located in South Asia. It is the seventh largest country by geographically area, and second-most populous country in world with over 1.18 billion people. </li></ul><ul><li>India is surrounded by the Indian ocean on the south, Arabian sea on the west and the Bay of Bengal on the east, therefore India is a peninsula. </li></ul><ul><li>It is also bordered to Pakistan on it’s west; china, Nepal and Bhutan to it’s north; and Bangladesh and Burma to it’s east. </li></ul>
  12. 12. India- what is it like <ul><li>The Himalayas and Thar Desert are the main reason for the climate in India. The Himalayas prevent cold Central Asian Katabatic from blowing in, keeping the Indian subcontinent warmer than other locations. On the other hand the Thar Desert is responsible for the southwest summer monsoon winds, that occur during June and October, and provide majority of India's rainfall. </li></ul><ul><li>The four major climates in India; tropical wet, tropical dry, subtropical, humid and montane </li></ul>
  13. 13. India - what is happening <ul><ul><li>In India the area under non-agricultural uses has increased due to increases in development activities; housing, transportation systems etc. Also the society cannot produce sufficient foods due to the quality and depth of the soils. </li></ul></ul><ul><ul><li>In India about 130 million hectare of land {45% of total geographical area} is affected by serious erosion through ravine and gulley, shifting civilizations, enormous amount of waste, sandy areas, deserts and water lodging. </li></ul></ul><ul><ul><li>Soil erosion by rain and river that take place in hilly areas are caused by landslides and floods; cutting down fire wood, livestock grazing and construction of roads have all lead to heavy soil erosion. </li></ul></ul><ul><ul><li>Wind erosion causes expansion of deserts, dust and storms. Moving sand covers the soil and makes it dry and unable to use. </li></ul></ul><ul><ul><ul><li>Of the 16 rivers in the world which severe erosion, 3 of India's rivers; Ganges, Brahmaputra and Kosy occupy 2 nd ,3 rd and 12 th place respectively. </li></ul></ul></ul>
  14. 14. India - how to prevent it <ul><li>One way to prevent soil erosion in India, is that the government could plant more trees because the roots hold the soil in place. </li></ul><ul><li>Another way is that the soil/crops have to be fenced of from cattle because they usually overgraze the soil which leads to soil erosion </li></ul><ul><li>Soil erosion prevention doesn’t always mean, how to stop soil erosion, but means how to treat the soil. The soil also needs the correct treatment to stay fertile. </li></ul><ul><li>The gullies are also very important because they are a big part in soil erosion. To prevent gullies, dams must be built and nature should surround it: rocks, trees etc. </li></ul><ul><li>Protection of crops from wind and water is necessary. Crops and soil should be covered from dust storms and land slides. They can be built on higher lands therefore water cannot affect it. </li></ul><ul><li>Vegetation should be looked after and not left to dry. Good farming techniques should be used. </li></ul><ul><li>Rubbish left for a long time has toxic dieses that can harm the soil that. </li></ul>
  15. 16. <ul><li>For the last four decades there has been sustained scientific interest in contemporary environmental change in the Sahel. It suffered several devastating droughts and famines between the late 1960s and early 1990s. Speculation about the climatology of these droughts is unresolved, as is speculation about the effects of land clearance on rainfall and about land degradation in this zone. However, recent findings suggest a consistent trend of increasing vegetation “greenness” in much of the region. An alternative adaptation model has emerged to counter the degradation model. Limited ground studies have shown that some farmers and communities have adapted to the changes during the droughts experienced in the Sahel and improved management of water and soil fertility that increase production. As these change increase returns, farmers invest in more inputs, livestock, and crop diversification. This suggests that they are moving toward a more positive equilibrium point than in the degradation trajectory. While promising in that it shows that success can be achieved with and without outside intervention, these success stories serve a broader purpose by suggesting model strategies that might be pursued. </li></ul>
  16. 17. <ul><li>Soil erosion is a global issue because of its severe adverse economic and environmental impacts. Economic impacts on productivity may be due to direct effects on crops/plants on-site and off-site, and environmental consequences are primarily off-site due either to pollution of natural waters or adverse effects on air quality due to dust and emissions of radiatively active gases. Off-site economic effects of erosion are related to the damage to civil structure, siltation of water ways and reservoirs, and additional costs involved in water treatment. There are numerous reports regarding the on-site effects of erosion on productivity. However, a vast majority of these are from the U.S., Canada, Australia, and Europe, and only a few from soils of the tropics and subtropics. On-site effects of erosion on agronomic productivity are assessed with a wide range of methods, which can be broadly grouped into three categories: agronomic/soil quality evaluation, economic assessment, and knowledge surveys. </li></ul>
  17. 18. <ul><li>Agronomic methods involve greenhouse and field experiments to assess erosion-induced changes in soil quality in relation to productivity. A widely used technique is to establish field plots on the same soil series but with different severity of past erosion. Different erosional phases must be located on the same landscape position. Impact of past erosion on productivity can also be assessed by relating plant growth to the depth of a root-restrictive horizon. Impact of current erosion rate on productivity can be assessed using field runoff plots or paired watersheds, and that of future erosion using topsoil removal and addition technique. Economic evaluation of the on-site impact involves assessment of the losses of plant available water and nutrients and other additional inputs needed due to erosion. Knowledge surveys are conducted as a qualitative substitute for locations where quantitative data are not available. Results obtained from these different techniques are not comparable, and there is a need to standardize the methods and develop scaling procedures to extrapolate the data from plot or soil level to regional and global scale. There is also a need to assess on-site impact of erosion in relation to soil loss tolerance, soil life, soil resilience or ease of restoration, and soil management options for sustainable use of soil and water resources. Restoration of degraded soils is a high global priority. </li></ul>
  18. 20. Y10 Geography Homework Unit: C7B Title: Managing Desertification Date: 4 th & 10 th May 2010 By Alec Christie
  19. 21. The American problem In America there used to be massive herds of bison which would stay clustered in tight herds for safety from predators. Their hooves and urine killed the moss while desirable plant seeds were pounded into the soil to germinate and also pounded organic materials into the soil which aided plant growth. The bison would then move on allow the plants to grow, preventing desertification. However because now there are cattle ranches with cattle roaming unopposed by predators and free to roam and do not trample and destroy the weeds and other inedible plants that like the bison did and this blocks sunlight and reduce plant growth. They also do not tread organic matter into the soil as they are sparsely spread out and this means there is less water retention in plants and less plant growth. This is creating an American Sahara However Don and Cleo Shaules, near Billings, Montana, have embraced a new idea of using cattle to do the job the bison's once did.
  20. 22. The American solution With heavy animal impact the Shaules have successfully trampled cactus and sagebrush into the dirt, while &quot;rototilling&quot; the soil to favor new seedlings. The rich, brown soil humus increased from 1/4 inch up to 1 1/2 inches in just ten years, and the Shaules have been able to more than double their livestock numbers. “ We wintered our &quot;herd&quot; of one cow on the most brittle, erosion-prone part of our land. Hay was put out in a different spot each day, and any that was not eaten was trampled into the ground, resulting in an explosion of new seedlings and growth in spring.” By mimicking the historical sequence of grazing with the aid of carefully laid out fences, to put more animals in smaller spaces for shorter periods of time. They also herd the animals, or put feed or supplements in areas where the impact is especially desired. The impact of the animals effectively breaks down old plants while also effectively ‘immunises’ the landscape with bacteria in the form of manure.
  21. 23. Afforestation in the Sahel “ Where 20 years ago there was barely a tree, there are now 50 to 100 per hectare. Production of cereals has soared” Satellite images taken this year and 20 years ago show that the desert is in retreat thanks to a resurgence of trees. Which are mainly ana trees ( Faidherbia albida ), a type of acacia, which is itself a kind of energy crop. Wherever the trees grow, farming can resume. Tree planting has led to the re-greening of as much as 3 million hectares of land in Niger, enabling some 250,000 hectares to be farmed again. The land became barren in the 1970s and early 1980s through poor management and indiscriminate felling of trees for firewood, but since the mid-1980s farmers in parts of Niger have been protecting them instead of chopping them down. By also combining the project with simple measures such as ditches and holes to catch scarce rainwater and save it for irrigation, the programmes are helping communities in Niger re-establish control over desertification, simultaneously halting the march of the desert and helping to prevent famines like the one that hit Niger in July 2005. Farmers in the Sahel are reclaiming the desert by turning its barren wastelands into green, productive farmland, that could potentially be used as a base for bio-energy feedstock production.
  22. 24. Afforestation in the Sahel <ul><li>&quot;The results have been staggering&quot;, says Chris Reij of the Free University Amsterdam in the Netherlands, and are due to a &quot;virtuous circle of benefits&quot; between trees and their surrounding landscapes. &quot;Leaves and fruits provide food, fodder and organic matter to fortify the soil,&quot; for instance. &quot;More livestock means more manure, which further enriches the soil enabling crops to be grown, and spreads tree seeds so new trees grow. The trees also provide shelter for crops and help prevent soil erosion. In times of drought, firewood can be sold and food purchased to tide families over.” Given the benefits of encouraging tree growth, the practice is hoped to passed on to neighbouring countries, including Mali, Senegal and Burkina Faso. </li></ul>
  23. 25. Managing irrigation and natural waterways in North Coast Orchards This project was part of a wider project to combat soil erosion in the North Coast of Australia which is badly affecting landowners there. The site helped in the project was an old macadamia orchard which had been established with little regard for natural watercourses. As a result there was extensive sheet erosion with exposed tree roots, and gullies had formed where water flows concentrated in the orchard. The damage to the orchard floor meant machine-harvesting in those areas of the orchard was ineffective. The new landowner of the site wanted to reduce the dramatic soil loss and improve machine-harvesting while maintaining existing production levels.
  24. 26. The Solution Firstly gullies running down between the lines of trees were filled with large gravel. Some trees in the way of natural flow lines for water, and also trees which over-shaded areas stopping sunlight getting through to the grass, were removed and others pruned to help grass to grow over the top of the gravel, which would allow machine-harvesting. The filled gully functioned as both a subsurface and surface drain which allowed water to flow across the tree rows and small rock check dams were installed to slow the water down and encourage sediment deposition rather than the water just washing the organic matter out of the orchard. After the scheme the land’s active gully erosion and sheet erosion through the orchard had been greatly reduced by slowing the water flow and allowing sediments to improve the soil structure and resist soil erosion. The extra light from removing specific trees also improved groundcover and because sediments were being trapped within the orchard, rather than ending up in dams and watercourses, the soil composition and structure benefited and plants were able to obtain the water and nutrients they needed. Another positive of the scheme was that the orchard’s production was not been interrupted or set back by the erosion control works so the landowner really ended up with a win/win situation.
  25. 27. <ul><li>In the border region of Burkina Faso, lies the Tin-Akoff pasture. Its users are from Burkina Faso, Mali and Niger and belong to two social groups. The organisation Walde Ejef is using the project to try to: </li></ul><ul><li>Increase pastoralists’ knowledge of their natural resources, </li></ul><ul><li>To establish a decentralized framework for teamwork among landowners, </li></ul><ul><li>And to provide capacity building for those involved in combined management from all the countries. </li></ul>Managing Shared Pastures in Beli
  26. 28. The project hoped to increase pastoralists’ knowledge of their natural resources using village debates, posters and video as communication tools and accompanied by foresters from the area, they were able to discuss with local people the state of their natural resources, the pressure on them and the best ways to preserve them. By giving the local people a bigger voice and teaching them about how to use the environment sustainably, like cutting down trees for fuel but also replanting trees and managing overgrazing and over-cultivation on some parts of the pastures, the problems that caused the terrible famines in the past in the Sahel region will hopefully be combated and solved by the local people. They now have the understanding to farm sustainably and be aware of the dangers that are associated with bad agricultural practices. They will also be able to communicate with each other and work out ways, that are most beneficial to them, to maintain their levels of productivity but without harming the environment and allowing desertification and soil erosion to get out of hand again. Not only this, but people will also be able to live in adequate housing without having to take from the environment to build their own houses, deforestation to get wood for building materials.
  27. 29. Desertification in Gansu
  28. 30. Desertification in Gansu <ul><li>Gansu is in the northern part of China were desertification is serious this picture underneath shows snail shells, showing that it used to be green land with trees and water there are still rivers but they expect them to dry up soon. </li></ul>
  29. 31. Desertification in Gansu <ul><li>What are people doing to stop desertification in the region a anti-desertification project in Gansu is in effect, the Asian Development Bank is working with the State Forestry Administration of China on the Silk Road Ecosystem Restoration project, designed to prevent degradation and desertification in Gansu. It is estimated to cost up to US$150 million. </li></ul><ul><li>It is being approached by several ways: </li></ul><ul><li>Tree planting is expensive and single trees often do not survive but bands of trees stand a better chance. China increased its tree cover by 14% and has reduced sand dune build up by up to 64% in some areas </li></ul><ul><li>Controlling Grazing: by reducing the number of animals per hectare and also by upgrading the grasses to more durable types </li></ul><ul><li>Wind turbines: replace the use of fuel wood with electricity. </li></ul><ul><li>Land rights: by giving long leases to farmers, they can invest in good practices and soil conservation measures that they and their families can benefit from. </li></ul>