Save Soil on Sloping Fields

Backgrounder

Conserve soil on sloping maize fields by digging ditches along the contours and filling them with maize stalks. The ditches stop soil from washing away and the soil and maize stalks make a compost which improves soil quality.  This method also helps control white grubs.

Losing soil is a problem for farmers who must plant crops on sloping land.  Farmers at a co‑operative in Guatemala know a way to conserve soil where they plant maize.  It is a good alternative to burning corn stalks after the harvest.  This method stops soil from washing away down hillsides, and it improves the quality of the soil.  It also helps control white grubs.

After the maize harvest, mark the contours on your land with stakes, using the A‑Frame method.  Cut the maize stalks in the field. Place the maize in rows on the hillside along the marked contour.  Pile them up to make a barrier that is 1/2 metre high.  Dig a ditch on the uphill side of the row of stalks.  The ditch should be 30 cm deep and 30 cm wide and it should run parallel to the row of stalks.  Put the soil you dig from the ditch on top of the piled‑up maize stalks.

Now you have a long ditch running along the contour of your land.  Below that, running alongside it, is a long, narrow compost pile of maize stalks and soil.

You can also plant a living barrier of grass or trees on the downhill side of the pile of maize stalks.

As the maize is growing during the next growing season, the ditch will fill with soil washed down the hill by the rain.  But the soil will not go any further than the ditch.  The ditch and the barrier of maize stalks will prevent soil from being washed all the way down the hill.

At the end of the next growing season, start the process over again.  The ditches you dug last season will now be filled with soil.  Pile the maize stalks 1/2 metre high, this time on top of last season’s ditch.  Then dig a new ditch on the uphill side of this pile of stalks and put soil over the stalks.  Continue this process season after season.  What you are doing is something like making little terraces all the way up the hill.

Members of this co‑operative in Guatemala are using this method because they can see it saves soil in their fields.  It conserves soil because it halts the flow of soil down the hill.  Also, as the maize stalks decompose, they add organic matter to the soil.  The organic matter makes the soil better for crops.  And the soil mixed with the stalks speeds up decomposition.

White grub control: Another good thing about this soil conservation technique is that it helps control white grubs (scarabaeiform larvae) which are a major problem in Guatemala.  The grubs feed on the maize stalks so by moving the stalks, you move their source of food.  The insects will follow their food and migrate to the piled‑up stalks.  They will lay their eggs there.  And they will attack the stalks piled up in the row instead of the crops.  The next year a bit of lime or ashes sprinkled over the maize stalks kills the grubs before you seed.