Soil in focus
Soil in focus 6:
Soil cathedrals in the landscape
Termites are small organisms compared to humans, yet they create structures –these large mounds- that are clearly visible in the landscapes of Africa, Asia, Australia and America. There are about 1000 different termite species in Africa and about 360 in Australia. Termites influence the local ecology, especially the soil. Organisms are the engine for soil formation as they process and incorporate large amounts of dead organic material into the soil, thereby changing its properties. This is all the more important in some of the old and weathered soils in Africa, where organic matter is the main source of natural soil fertility. The soil of and around termite mounds have high porosity, affecting water flow and storage in the soil and they have a higher pH and organic carbon content and nitrogen.
Termite hill near Otavi, Namibia
The scientific name of this soil from South Nyanza in Kenya, is a Vermic Phaeozem, where Vermic points to the termite activity in terms of biopores and animal burrows. The reference group Paeozem indicates a soil with a high content of organic matter, in this case created by the termites activity.
Termite mounds often form initially around a tree or a pole. The mounds may form to some meters above the ground and extend to various meters below the surface. The tunnels have a complex internal structure with ventilation shafts for air and temperature regulation, fungus chambers for nourishment and access and transport pathways.
Specific vegetation grows on and around termite mounds that attract herbivores that feed on this apparently more nutritious vegetation. Farmers in Sub Saharan Africa find their yields decreasing because of low and decreasing soil fertility. They are aware of the beneficial properties of termite mound soil. Farmers are integrating termites in their farming system. Crops like banana are planted near them, wood is buried in the soil to attract termites. And sometimes the soil of termite mounds is harvested or ploughed as soil improving amendment. Although there are termites that feed on agricultural crops, they use the leaves for their own farming –fungus gardens-, they do that mainly on exotic crops and not all species are harmful for agricultural crops. These are smart practices using local knowledge of farmers, who depend on agriculture for food.