Soil erosion, generally posses an irreversible threat to soil fertility. Erosion carries away the most fertile parts of the soil: the topsoil and the finer clay fractions which are rich in humus and nutrients.
Even low erosion rates which are almost invisible can over the years severely damage your soil.
So, it is important you protect the soil in your cocoa farm.
Causes of Soil Erosion in Cocoa Farm
Ground vegetation usually thins out and leaves the soil uncovered during the dry season.
So, when it rains, the topsoil washes away, affecting soil fertility. If there is no soil cover, not only sloping land is prone to soil erosion but also flat fields can be severely affected.
Factors affecting soil erosion include:
- Soil types (silt, sand loam)
- Soil structure
- slope of land
- Soil cover
- rainfall intensity
When the land has fine tilth soils that have no vegetative cover, situated on a slope are more prone to erosion. Carry out a risk assessment to find out which parts of the cocoa farm are most prone to erosion. Based on this assessment, develop a management plan to reduce soil erosion.
How to Prevent or Manage the Soil Erosion
Practically you can prevent or manage erosion by;
- MULCHING
Mulching is done by spreading dry plant materials or plantain pseudostem around the base of the cocoa plant. This prevents the direct impact of raindrops that can wash away the soil.
- COVER CROPPING
Cover crops (leguminous and non-leguminous) such as Mucuna puriens, Tropical kudzu (Pueraria phaseoloides) , Stylosanthes sp. may be planted between the rows of cocoa plants to manage control soil erosion and weeds on the farm. This protects the soil and sometimes provides nutrients to the soil when you use nitrogen-fixing crops.
- USE OF SHADE TREES
The layers of the canopy of natural forests reduce the impact of raindrops on the soil. The water drops reach the soil with less speed and so, are not able to splash the soil particles. This, to a larger extent, prevents the soil from washing off.
You can achieve this by leaving or planting shade trees on farms during land preparation. Soil erosion control is especially important in areas near water sources and in steep areas. Even when you don’t farm in those areas, you should still plant trees against soil erosion.
- USE OF “STOP-WASH LINES”
Use blockades or barrages across the slope to reduce the speed of water movement and also trap soil. A common type of such blockade is “stop-wash lines”.
- TERRACING
A terrace is a levelled section of a sloppy land that is used for cultivating crops. When digging the terraces, it is important that you keep the fertile topsoil aside and later spread on top of the finished terrace. You may grow cover crops or grass on the slopes between the terraces to prevent soil loss.
- DIVERSION OF SURFACE RUN-OFF
Construct drains and ditches to divert excess water from the farm.
