Be Prepared for Life

Activity Kit Five:
"Living with the Soil"

Part 2. Saving our Soil

DO YOU KNOW -
HOW SOIL IS LOST FROM YOUR LAND?

Bare soil is soil at risk! Wind storms [dust devils] carry exposed topsoil away. Heavy rains carry topsoil away leaving sand banks in river mouths. Sometimes there is so much sand blowing about we can feel it stinging our legs. In the rainy season our streams and rivers may run red brown with the soil they are carrying away. More and more stones and tree roots appear on the surface each year. Deep gullies are eaten out of slopes. Paths and earth roads become hollowed and rutted as their soil disappears. They become streams of water across the veld in the rainy season. Soils may also be removed by underground streams flowing through porous soils. Soil erosion is a natural process that is accelerated by ignorance and abuse of the soil, or is combated by informed concern and action. Because it affects us all, not just the farmers who grow our food, we all need to be involved fighting soil erosion.

Project 3: Going... going... saved!

HOW MUCH SOIL IS BEING LOST?

  1. Hammer 10 square wooden pegs into the ground at various places.
    Leave at least 8 centimeters protruding.
  2. Wrap a piece of sticky tape, sticky side outwards, around each peg.
  3. Come back one week later and record - how much dust is blowing about and from what direction?
    Where is this soil coming from and how can its loss be controlled?
  4. Nail 5 tins onto 5 pieces of wood and embed them in your nearest river or stream before the rainy season. Pack stones over the planks so that the tins will not be lost.
    Calculate the area of each tins bottom.
    eg. Area of tin = The diameter x 3,14
    Record your answers in square centimeters.
  5. Once the stream flood has abated collect the tins.
    Mark their position on a map. Decant the water and allow the sediment in each tin to dry out.
    Measure the depth of the sediment in each tin and calculate the volume of sediment deposited at that point in the stream. Area of tin bottom x the depth in centimeters.
  6. Contrast the sedimentation at different points in the stream. Over 300 million tonnes of soil are lost like this each year nationally.
  7. Make a wooden frame 20 x 20 x 5 cm.
    Fill it with soil. Place large washers or coins on its surface.
    Expose it in a rainstorm and measure the amount of soil above each washer after the rain.
  8. Take the lid of an old shoe box and spread 1 cm of dry Plaster of Paris inside the lid. Expose it to a strong rain storm until its upper surface is wet through. Recover the plaster mould and allow the rain prints to set hard. Study the splash patterns of different rain types.
    The splash energy in 25 mm of rain falling for one hour is equal to the energy required to plough the same area to a depth of 250 mm. This is the power of rain to erode exposed soils.
  9. Study your area and fill in this checklist.

    SIGNS OF SHEET EROSION ON THE SURFACE

      YES NO
    • Are there any pebbles or large soil particles at the surface?
    • Are there any rivulets on the surface?
    • Are the roots of trees or plants exposed?
    • Are any plants growing on soil mounds?
    • Are any stones standing on soil pedestals?
    		   

    HOW TO PREVENT EROSION

    In dry areas everything possible needs to be done to keep rain water on the land as long as possible to prevent soil wash aways and increase soil moisture.
  10. Find an exposed soil slope. A cutting or even a load of sand or clay will do fine.
    Identify a protected and an unprotected slope. If no plants are growing on the slope cover a portion with a single layer of a hessian sack cut open to act as soil cover. Pour a bucket of water slowly down each slope noting how far the water reaches in each case.
    Study the route of the water.
    How can water be retained longer on each slope?
    Are there any tiny gullies forming on the slope?
    Experiment with different methods of slowing down the water.
    Try these ideas on a mini-scale.
    Embankments, stone walls, logs across the slope.
    Try planting grasses on the slope.
    Discuss the most successful ways of combating soil loss on a slope.
    Find an eroded area near you and develop ways and means of protecting the slope in co-operation with the land owner.
  11. Study your area and fill in this checklist.

    WOULD THESE EROSION CONTROL METHODS WORK HERE?

      YES NO
    • Is there a hard crust to be broken up?
    • Would planting grass strips help?
    • Would a wooden chip mulch help here? [See Project 5]
    • Would it help to build a barrier across the slope [tree, stones, brush wood]?
    • Is there a gully to be dammed?
    • Should a path be protected here?
    • Should this land be ploughed differently?
    • Should fewer animals be grazed here?
    • Should indigenous plants be planted on river banks?
    		   

Project 4: Save the wetland - save the soil!

  1. Identify your closest wetland area. [See Kit 4: Project 11].
    Map the wetland. Indicate the main water channels. The extent of the swamp plants and reed beds.
    Map the position of any alien plants.
  2. Look at the areas around this wetland.
    Has any of it been filled in, built on or reclaimed? Is there any sign of attempts to control the erosive force of the water where once natural wetland plants might have grown. Map in where you think the old wetland borders were.
    Are there any signs of erosion around the wetland fringes?
  3. Collect water samples at different depths using a white disk and a canoe.
    The depth at which a white disk disappears beneath the water is a measure of the sediment load it is carrying. A white plastic side plate screwed onto the end of a broom handle works well.
    Measure the turbidity above and below the wetland area as well. How do wetlands effect the quality of water? [See Kit 4: Project 4 if you want to measure the pollution levels in the water.]

All wetlands in South Africa are in trouble and need to be conserved. They act as flood busters, water filters, wildlife sanctuaries, places of food and beauty. If you want to know more - Read Enviro Facts Sheet 42 Wetlands [Pick 'n Pay]. If you want to do more contact The Department of Environment Affairs : Wetland Conservation Programme. PB X447, PRETORIA, 0001.

DO YOU KNOW -
HOW YOUR SOIL CAN BE IMPROVED?

All soils can be improved by composting. Kit 1: Project 11,introduced the concept of composting, Kit 3: Project depended on effective composting and it will be expanded in Project 5 below. Compost is natures way of recycling nutrients back into the soil. Well decomposed compost forms a dark natural soil glue called humus. Humus helps to hold soils particle together in larger clumps. This makes the soil particles larger letting water and air move through the soil more easily. Humus shelters and provides food for living organisms. Well composted soil absorbs water easily and remains moist longer, carrying nutrients to plant roots - and encouraging growth. Farmers can never make enough compost [30 tonnes per hectare is needed] and so have to use fertilisers to replace plant nutrients removed by their crops. Small scale gardening is different!

Project 5: Enriching your soil

  1. Each square meter of your garden needs 2 buckets of compost per year. Compost can be made in pits or in covered heaps.
    Dig out a pit 2 x 2 m x 1,5 m or mark off a 2 x 2 m area.
  2. Place a layer of small branches [15 cm] at the bottom of the heap or trench to allow air to reach it.
    Place a wooden pole of about 15 cm diameter in the heap and build the heap around it.
  3. Add about 20 cm of green waste material. Kitchen wastes, hedge and lawn clippings, sawdust, shredded paper, leaves, straw, or reeds.
  4. Add 5 cm of manure or 1 kg of lime or bone meal, or even seaweed.
    This will start the process.
    Water this heap thoroughly.
  5. Spread 3 cm of soil over this.
  6. Repeat steps 3 to 5 until the heap is about 1,5 meters high. Remove the pole to ventilate the heap.
    Keep your heap warm and moist, by covering with sacking and watering as needed.
  7. Start a second heap
  8. Push your hand into the first heap from time to time to feel the heat.
    When it cools down after a few weeks, turn the whole heap over to speed up decomposition.
  9. Your compost should be ready to dig into the soil after 3 months.
  10. By starting a new heap at regular intervals you can have compost all year round.
  11. Consider starting a Scout compost heap management programme for your neighbourhood gardens. It would be a wonderful way of conserving the soil and earning some patrol funds at the same time.
Sacking over the heap preserves moisture at the surface. Any ground cover will protect soil, save water and encourage plants to grow, while it controls weeds. In no time plants look healthier, greener and bigger. This process is known as mulching. You can use almost anything that decomposes as mulch. Grass clippings, straw, small leaves, bark, sawdust, wood shavings, even compost. When it has rotted away it can be dug in. Mulching is particularly important at the start of the dry season. It protects the soil with a life sustaining blanket.

Part Three: Using soil efficiently

 © Copyright 1991 - 1994
Dr Frank Opie for the South African Scout Association