1. Land husbandry in drought prone areas MSc 556
Seminar topic: Influence of termites on soil properties
Date: 10th April 02
Course Organiser: Mr. Paul D Smith
Franco Cube Kalisto

2. Introduction
Termites are social insects which live in nests known as termitaria
termites are sometimes known as white ants
approximately 1900 living and fossil species so far known
majority are found in the tropics
the termitaria serve to house and protect the colony
store food and maintain optimum environment
It produces a condition of homeostasis by
self regulation of optimum conditions for development
maintenance and reproduction of the society (Emerson; 1956)

3. Classification of termites
The colony of termites consists of several castes
which are morphologically distinct
control of the proportion of the different castes is by
selective cannibalism of soldiers or
reproductive on the part of the workers
the reproductive castes consist of
males (kings) and females (queens)
Sterile castes are the workers and soldiers

4. Castes development Soldiers develop from nymph
Workers comprise the bulk of the population
Reproductive castes develop from alates

5. Reproductive castes/Queen
Gravid female

6. Reproductive castes/Drone

7. Sterile castes Are the workers and soldiers
the sexual organs is suppressed

8. soldier
Soldiers have modified mouthparts
Larger heads and pigmented

9. Classification/ cont.
Termites can also be classified base on the type of nests they construct
the most important types are the Colorado, the subterranean ground nesting termites
responsible for damage to constructions
construct earthen tubes from the nest to food source
a break in the nest would quickly be detected and repaired by the workers

10. Termitarium/mound

11. Section through mound

12. Effect of termites on soil properties
Termites can affect soil properties by their burrowing and excavation
when searching for food, constructing living space or storage chambers in the soil or above the ground
the burrowing and excavation activity bring much of the fine materials to the surface and cement into concrete like material to the underlying soil
arresting normal soil development processes
Soil porosity is reduced in soils without termites more silt and sand added to soils in areas where termites present

13. Effect of termites on soil properties/ cont.
Termites play a major role in flocculation of soil organic matter
soils with low OM and low active clay content termites control soil aggregation
Form aggregates by cementing soil particles into massive structures that are extremely resistant to erosion
Termites worked materials are stable than surrounding ground mass because of the saliva added when building their structure
Soil aggregates resulting from termites activity are more stable and not easily dispersed in water compared with soil undisturbed by termites presence
The pH of mounds is higher than that of soil from which is constructed
increased in pH is associated with accumulation of calcium carbonate
decreased in pH is associated with high organic matter content in mounds

14. Effect on soil/cont Termites activity accelerates soil erosion
By removing plant cover consequently exposing the bare soil surface to erosive forces
ingest or remove organic matter which would otherwise be incorporated into the soil and thus making the soil more susceptible
Bulk density of termites modified soils is lower compare with soils not affected by termites activity
because of increased porosity or incorporation of organic matter
re-packing of soil by termites also minimises soil pore spaces which increases soil bulk density

15. Crusted/degraded soil
Termites activity repair the damage caused by soil degradation or crusting through excavation across crusted surfaces
Improving soil porosity and water infiltration
Transport of materials to soil surface loosens the soil
This has a critical influence on soil properties
enabling the soil to resist the degrading processes of soil such as water erosion and logging
Termites activity enhances the water balance of the crusted soil
by increasing infiltration amount, soil water storage and drainage

16. Soil macro-nutrients
Termites mounds contain more nutrients than the underlying soil
mainly because of nutrient enrichment by the soil feeding capacity to select organic particles from poor medium
use of organic materials (saliva & faecal) to cement soil particles or aggregates
The enrichment in the mound affects carbon/nitrogen ratio of the internal and external wall
Due to activity of soil micro-organisms in the mound compartment
Mounds of fungus feeding species has low carbon /nitrogen ratio

17. Soil macro-nutrient/ cont.
However, soil feeding termites retain SOM in each fraction of their mounds
SOM is protected from active mineralisation due to its distribution within the soil fraction
The SOM enrichment of the mound soil indicates that the structure is not merely shelter
Because of the ecological significant of the soil feeding termites mound in terms of termites nutrition and SOM cycling
Calcium content of mounds is higher than that of the soil from which they are built
calcium is derived from ingested plant tissues

18. Effects on availability of soil nutrients
Termites affect nutrient availability by transporting soil and organic matter to mounds and surrounding structures
eventually redistribution of these elements by erosion and decomposition enriches the surrounding soils
Great amount of nitrogen leaves with the colony annually in the bodies of alates when moving to establish a new colony
majority die before establishing a new colony
the decomposed bodies make significant contribution to the accession of nitrogen

19. Alatecarps/white ants

20. Water infiltration
Termites harvesting activity create dense networks of underground galleries connected to soil surface by foraging holes through which water penetrates
Infiltration capacity of foraging holes is very high as it does not limit water penetration
Rather the limiting factor to the influence of micro-pores on infiltration is the ability for micro-pore to intercept running water
Sometimes despite presence of micro-pores effect of runoff is not measured
mainly because the micro-pore location is not favourable for intercepting runoff

21. Influence on Infiltration
Gallery systems resulting from termites activity have profound effect on;
Soil pore space, infiltration of water into the soil, aeration and penetration of plant roots
By increasing infiltration termites increase soil water storage capacity and promotes vegetation development
Termites however, decreases the infiltration rate by reducing the amount of litter

22. Soil water storage, Evapo-transpiration and drainage
The influence of termites on soil enhances soil hydraulic conductivity and infiltration
because the soil structure has been modified and amount of water input by infiltration
ET rate of soil affected by termites activity is low compare with soil without
attributed to improved drainage by termites activity
in deeper soil layers termites activity enhances soil water recharge
water being protected from evaporation when it drains to deeper soil layers
activity of termites and mulch increases the water storage capacity of the soil
reduce runoff and increase soil water content through vegetative growth

23. Soil water storage

24. improves soil structure by loosening and water infiltration
Plant production
Termites play an important role in primary production affecting growth through two main processes
improves soil structure by loosening and water infiltration
enhances decomposition of surface applied organic materials stimulating nutrient release which can be used by growing plant
Affect root growth through their influence on soil structure
pore space, permeability and water logging capacity, aggregation and stability of aggregates

26. Economic importance
They are abundant in tropical and subtropical environments where they help break down and recycle up to one of annual production of the dead wood
become pests when their appetite for wood and wood products extends to human homes, building materials, forests and other commercial products
in US annual losses to termites infestation are estimated at more than $ 800m
consume standing forage plants that would otherwise be eaten by livestock

27. Economic importance/ cont
Destroy valuable pasture plants such as legumes
consume dry grass and mulch resulting in increased soil moisture evaporation
cemented materials from mounds of variety of species have been used for
roads and path, construction, tennis court, earth floor in buildings, bricks for construction
in Africa wet termites mound soil is used as medicine
for curing chicken pox
eaten make excellent human diet and used for marriage

28. Control
In plantation seedlings can be protected by mechanical cultivation and using dieldrin in the planting holes
destroy the mounds and remove the queen
treat soil with insecticide
fumigation
clearing rubbish around construction