Status of Women in Islam
Soils of the tropical savannas
The soils of the tropical savannas, along with the distinctive wet/dry climate, are a major determinant of vegetation in the region, and of potential land uses. Soil is an outcome of five broad factors: parent material, climate, relief/slope, time and organisms. |
Infertile soils
Given the variations in all of these in the savannas it is no surprise that there are many different soil types in evidence in northern Australia. Generally speaking the combination of these five factors has resulted in soils which are characterised by their infertility, although there are exceptions. In other words, very old and already well-weathered parent material has in many areas been leached of nutrients by the very high summer rainfall. Those areas of greatest wet season rain tend also to be the most infertile. Lateritic soils for example, which are the most weathered and infertile of all soil types across the tropical savannas, are found in areas closer to the coast with high summer rainfall.
Nutrients levels in savannas soils are further reduced by aerobic bacteria which are particularly active in areas where the temperature remains above 25oC degrees for substantial periods of time. The activity of these bacteria under such conditions occurs at a rate above that of plant growth, thus breaking down plant matter faster than it is produced. The result is that soils are lacking in humus which contributes much of the nutrients to soil under different conditions.
Variation in soil factors
Of course, soil characteristics are highly dependant on localised factors and so can vary considerably within a small area; there are probably different soils within an average paddock for example.
There are however a few generalisations to be made about the soils of northern Australia: * soils are more fertile in the south-east sector of the tropical savannas while in the north-west shallow lithosols (skeletal soils in which only the 'bones' of the soil remain)
The soils of the tropical savannas, along with the distinctive wet/dry climate, are a major determinant of vegetation in the region, and of potential land uses. Soil is an outcome of five broad factors: parent material, climate, relief/slope, time and organisms. |
Infertile soils
Given the variations in all of these in the savannas it is no surprise that there are many different soil types in evidence in northern Australia. Generally speaking the combination of these five factors has resulted in soils which are characterised by their infertility, although there are exceptions. In other words, very old and already well-weathered parent material has in many areas been leached of nutrients by the very high summer rainfall. Those areas of greatest wet season rain tend also to be the most infertile. Lateritic soils for example, which are the most weathered and infertile of all soil types across the tropical savannas, are found in areas closer to the coast with high summer rainfall.
Nutrients levels in savannas soils are further reduced by aerobic bacteria which are particularly active in areas where the temperature remains above 25oC degrees for substantial periods of time. The activity of these bacteria under such conditions occurs at a rate above that of plant growth, thus breaking down plant matter faster than it is produced. The result is that soils are lacking in humus which contributes much of the nutrients to soil under different conditions.
Variation in soil factors
Of course, soil characteristics are highly dependant on localised factors and so can vary considerably within a small area; there are probably different soils within an average paddock for example.
There are however a few generalisations to be made about the soils of northern Australia: * soils are more fertile in the south-east sector of the tropical savannas while in the north-west shallow lithosols (skeletal soils in which only the 'bones' of the soil remain)