1. Introduction to managing desertification and soil erosion

6. Desertification and management of soil erosion By Muhammad Hamza

20. Y10 Geography Homework Unit: C7B Title: Managing Desertification Date: 4 th & 10 th May 2010 By Alec Christie

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.

22. The American solution With heavy animal impact the Shaules have successfully trampled cactus and sagebrush into the dirt, while "rototilling" 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 "herd" 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.

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.

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.

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.

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.

29. Desertification in Gansu