Bush burning may alter soil structure
BY custom, culture or social habits, ugandans living in predominantly rangeland areas set bushes on fire during the dry season.
By Thomas Pere
BY custom, culture or social habits, ugandans living in predominantly rangeland areas set bushes on fire during the dry season.
The bushes are burnt to encourage new growth for pasture. Godfrey Bawonga says that in his village, fire is used for clearing bush, because it is easy, quick and convenient.
But Stanley Afeku, an agricultural officer, says the effects of bush burning on soil vary greatly.
Frequency, duration and intensity of fire as well as soil characteristics must be considered.
Bush burning cannot cause changes in the structure of minerals in soil because the elevated temperatures are of brief duration. However, bush burning when soil moisture conditions are extremely low, may elevate temperatures long enough to ignite organic matter in the soil as well as alter the structure of the soil.
As vegetation matures, an increasing proportion of the nutrients on the site become locked up in the vegetation and are unavailable for further use until plants die and decompose. Low intensity fires speed up this recycling process, returning nutrients back to soil where they are again available to plants.
Under normal conditions, bush burning may increase nitrogen loss to the atmosphere that results from burning the litter layer.
Unlike soils, fire damage to plants depends upon the heat generated and growth stage of the plant at the time of burning. A dry, mature grass burns more readily and at a higher temperature than a green plant. It kills tissues of green plants above 60 degrees celcius.
Heat from the fire may kill seeds. Fire opens up bush land and changes the species of plants and animals that live on those plants.
The habitats of rodents and other small animals may be temporarily destroyed by bush fires. Nests of birds that nest on the ground burn and food is destroyed.
However some bird species increase in number where there is light burning because of the increase in grasses that produce seeds which the birds later feed on.
Peter Omony, an environment activist, says bush burning should be regulated so that the adverse effects are avoided. Alternatives include grass cutting for roofing and mulching.
BY custom, culture or social habits, ugandans living in predominantly rangeland areas set bushes on fire during the dry season.
The bushes are burnt to encourage new growth for pasture. Godfrey Bawonga says that in his village, fire is used for clearing bush, because it is easy, quick and convenient.
But Stanley Afeku, an agricultural officer, says the effects of bush burning on soil vary greatly.
Frequency, duration and intensity of fire as well as soil characteristics must be considered.
Bush burning cannot cause changes in the structure of minerals in soil because the elevated temperatures are of brief duration. However, bush burning when soil moisture conditions are extremely low, may elevate temperatures long enough to ignite organic matter in the soil as well as alter the structure of the soil.
As vegetation matures, an increasing proportion of the nutrients on the site become locked up in the vegetation and are unavailable for further use until plants die and decompose. Low intensity fires speed up this recycling process, returning nutrients back to soil where they are again available to plants.
Under normal conditions, bush burning may increase nitrogen loss to the atmosphere that results from burning the litter layer.
Unlike soils, fire damage to plants depends upon the heat generated and growth stage of the plant at the time of burning. A dry, mature grass burns more readily and at a higher temperature than a green plant. It kills tissues of green plants above 60 degrees celcius.
Heat from the fire may kill seeds. Fire opens up bush land and changes the species of plants and animals that live on those plants.
The habitats of rodents and other small animals may be temporarily destroyed by bush fires. Nests of birds that nest on the ground burn and food is destroyed.
However some bird species increase in number where there is light burning because of the increase in grasses that produce seeds which the birds later feed on.
Peter Omony, an environment activist, says bush burning should be regulated so that the adverse effects are avoided. Alternatives include grass cutting for roofing and mulching.