Describe the nature of soils under the following forest ecosystems:
1. Deciduous forest
2. Coniferous forest
3. Temperate rainforest
4. Tropical rainforest
5. Monsoon forest
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JOB MARY OKON
ReplyDeleteU2012/5020015
Deciduous forest can be defined as vegetation composed primarily of broad-leaved trees that shed all their leaves during one season.
Brown forest soils (alfisols, in the American soil taxonomy) develop under the deciduous forest. Broadleaf trees tend to be nutrient-demanding and their leaves bind the major nutrient bases. Thus the litter under this forest is not as acidic as under needleleaf trees and aluminum and iron are not mobilized from the A horizon. The predominant soil found in the deciduous forest biome is alfisol. This type of soil is characterized by a gray to grayish-brown coloration and a relatively high fertility. Alfisols form via the processes of weathering, eluviation and illuviation.They have a clay-enriched subsoil and relatively high native fertility. "Alf" refers to aluminium (Al) and iron (Fe). They are widely used both in agriculture and forestry, and are generally easier to keep fertile than other humid-climate soils, though those in Australia and Africa are still very deficient in nitrogen and available phosphorus. A large part of slowly decomposing soil humus is made up of the dead remains of fungi.
Coniferous forests are made up mainly of cone-bearing or coniferous trees, such as spruces, hemlocks, pines and firs. The soil profile of a coniferous forest is called a podsol .The soil has a humus layer just below the surface. The A horizon is grey in colour as it has lost its minerals through leaching. The B horizon is a reddish-brown colour as the minerals lost from the layers above are deposited here The C horizon consists of stones and rocks. Most podzols are poor soils for agriculture due to the sandy portion, resulting in a low level of moisture and nutrients. usually have higher organic matter because they have lower temperature which slow down the decomposition rate. However, these soils are highly weathered due to the seasonal temperature and precipitation rate along the year. Decomposers break down dead organisms (plants and animals) and use them as a food source in a process called decomposition. Monsoon forest, also called dry forest or tropical deciduous forest, open woodland in tropical areas that have a long dry season followed by a season of heavy rainfall. The trees in a monsoon forest usually shed their leaves during the dry season and come into leaf at the start of the rainy season. Monsoon forests are especially well developed in Southeast Asia and are typified by tall teak trees and thickets of bamboo. Latosols (predominantly yellow latosols Latosol is a name given to soils found under tropical rainforests with a relatively high content of iron and aluminium oxides. They are typically classified as oxisols (USDA soil taxonomy)or ferralsols Latosols are red or yellowish-red in colour throughout and they do not have distinct horizons like a podsol. The red colour comes from the iron oxides in the soil. They are deep soils, often 20-30m deep whereas podsols are 1-2m deep. The soil generally contains a thin but very fertile layer of humus dropped from plants and animals in the forest above, followed by an infertile second layer due to rapid leaching in the high rainfall. The third level, weathered bedrock, is common to almost all soil types. The latosol is completely reliant on the rainforest to maintain fertility, as all nutrients leach away quickly when the forest is felled and the layer of humus is no longer being replaced.
Soil chemical properties for a subtropical rain forest in the Nanjenshan Reserve, southern Taiwan, were examined to determine soil-landscape and soil-vegetation relationships. Redundancy analysis (RDA) showed that both topographic variables and vegetation types were needed to explain the variation in soil data. Soil properties that differed significantly among landforms were pH, available N, CEC, exchangeable Al, K, Ca and Mg. Levels of pH, exchangeable Ca and Mg increased in a downslope direction, and exchangeable Al tended to be higher in the upper slope soils.