COURSE: Number 1
TITLE:
Implement systems to control erosion
WORDING: The task is to learn about why soil erosion occurs, what
problem it creates and to test ways to reduce erosion problems
in Southern African villages
INTRODUCTION:
Erosion is a great problem in many countries of southern Africa as was shown very clearly
during the disastrous floods recently in Mozambique. It is a vicious cycle. With less
vegetation the rains beat stronger in the earth and they take more material into the rivers.
Less vegetation also means less organic matter, which results in less humus in the earth and
less capacity of storing water in the earth. It means that even more water runs to the rivers
and more material and nutrients are washed away. With less water in the earth the
vegetable production decreases and the erosion risk increases. The material accumulates on
the river bottoms so the river has less volume for the water. With heavy rains this results in
floods.
Simple systems exist which can help a lot in controlling the erosion. It is important to
know agriculture systems that reduce the problem. Systems that leave the earth covered as
much as possible, and where the residues are not burned. Especially on sloping land it is
important to prevent that nutrients and material are washed away. A method is to always
plant following the contours. Traditionally systems were made with stones and earth to
reduce erosion. Simpler systems can be made with vetiver hedges, which can grow under
almost any conditions. The big root system holds the plant very well and it functions as a
water dam both above ground and underground
DIRECTIVES:
1. (1 hour) Study why it is important to control erosion
 read pages 1-6 in Gaia Manual 1e "Conservation Farming"
 be able to explain about humus, organic material, preservation of water in earth, loss of
nutrients, accumulations in the rivers and lakes.
2. (1 hour) Study what can be done
 read Gaia Booklet 7e, " Water Harvesting and Saving", p. 2-6
3. (4 hours) Make a vetiver nursery at the school and participate in fighting erosion
 Find out where to get vetiver in your area
 Prepare a nursery in a swampy area or where you can irrigate - on a building weekend
or as a common action
 Start the nursery production and make sure that the work becomes part of the daily
routines.
4. (2 hours) Disseminate knowledge about the vetiver system
Introduce the vetiver system at an Open Sunday, and encourage others to start their own
nurseries
FILES:
Gaia Manual 1e "Conservation Farming"
Gaia Booklet 7e, " Water Harvesting and Saving", p. 2-6
www.gaia-movement.org (Gaia-Movement/Publications)