Effects of Termites on Soil Productivity and Growth of Plants on Mound Material

Effects of termites on soil productivity

Unlike earthworms, termites do not have a beneficial effect on soil productivity. This is because the digestive processes of termites aided by microorganisms in their gut, are generally more efficient than those of earthworms. Also, earthworms incorporate organic matter into the soil in a relatively uniform manner over a hectare of land. In contrast, termites mix plant residues into the soil only in the localized areas of their nests, while the remaining land area of the remains unmixed. This termite behavior can make it extremely difficult to provide cropland with the benefits of a protective crop residue mulch.

Termite activity in soil - soil fertility

Termites use nutrient rich salivary secretions and fecal material as cementing agents in the course of construction. Because of its higher clay content and usually higher cation concentration they increase the nutrients in soils. Termites remove soils from various depth and bring it to the surface in the form of covered mounds. Pathak and Lehri (1959) found that in termite mound 67% of clay aggregates had particle size greater than 2 micro meter.

Plant growth on termite mound material

Termite mound material often has a lower organic matter and nutrient content than surrounding undisturbed topsoil. This is because termites build their mounds mainly with subsoil, which is typically lower  organic matter content than topsoil. Crop growth in soil in areas where these mounds have existed is often poor, not only because of low nutrient content in the surface soil, but also because of the greater density of some of the mound material.

Termite mounds - effect of termite mound on plant growth

However, where the subsoil is richer in mineral nutrients than the topsoil, or is rich in clay compared to a very sandy surface soil, the material from abandoned mounds may provide islands of relatively high plant production, due to greater availability of phosphorus, potassium, calcium and moisture. On soils with a high water table, termites mounds may provide islands of better drainage and aeration that produce much better plant growth. In certain semiarid and savanna regions, the stable macro channels constructed by termites greatly increase water infiltration into soils that otherwise tend to form impermeable surface crusts.

Termite activity is a significant factor in the formation of soils of tropical and subtropical areas. These insects also have both positive and negative effects on current land use in these areas. They accelerate the decay of dead trees and grasses but also disrupt crop production, and even road construction, by the rapid development of their nests.

Before leaving the subject of termites, it should be mentioned that the bacterial metabolism in the guts of these widespread soil animals accounts for a substantial fraction of the global production of methane, which is an important greenhouse gas.