Soil Ecology
Soil Ecology interrelationships between living organisms and the environment in which they live. To define soil ecology one should be familiar first with the term ecology. A habitat along with the community it contains is a single working system and is termed as Ecosystem. The ecosystem consists of the community of organisms plus the associated physical environment. The main features of the physical environment are soil, water, climate, geology, topography and depth below sea level or altitude above it.
Soil has a particular significance in the ecosystem being partly important component of it but at the same time also constituting a specific partial ecosystem comprising biological and non-biological components and connecting them to the ecosystems as a whole. Whenever, the status of the ecosystem is concerned and the harmful processes studied and characterised, particular attention should be paid to the soil and its properties as it is a medium often determining the function, properties and even fate and possible development of the ecosystem. Soil represents the bulk of most ecosystems.
The basic and most important concept of an ecosystem is that everything is somehow related to everything else in nature. Hence, soil ecology comes forward to study these relationships. To study soil ecology, the understanding on the major types of ecosystems, viz, the sea, estuary and seashore, freshwater system, desert or dryland, tundra, grassland, forest, wetland and aquatic ecosystem, marine wetland ecosystem (mangrove, swamps, salt marshes), flood land, swamp, and marsh, bog and aquatic ecosystem are prerequisite. Soil ecology provides the scientific framework upon which soil conservation programmes or pollution monitoring schemes can be set up. One important way in which soil ecology differs from most other branches of soil science is that it can be properly appreciated or studied only through a multidisciplinary approach involving close cooperation by experts in several disciplines eg, soil microbiology, physics, chemistry, biochemistry, engineering, conservation techniques, management, biotechnology and agronomy.
Recently, the ecology of Bangladesh soils has been studied in the light of the stated facts. Land use and agricultural potential in Bangladesh have been identified by thirty agroecological regions and eighty eight sub-regions on the basis of (i) physiography (landforms and soil parent materials); (ii) soils; (iii) depth and duration of seasonal flooding; (iv) length of rainfed kharif and rabi growing periods; (v) length of pre-kharif periods of unreliable rainfall; (vi) length of the cool winter period; and (vii) frequency of occurrence of extremely high (>40'C) summer temperatures, etc. Agroecological regions and sub-regions are very broad units. The fertility status of these regions varies considerably due to the management of each and every piece of land by the farmers of different economic groups. The ecology of Bangladesh soils deserves special attention due to its geographic positions, soil forming processes, a large number of soil types and soil series, existence of some problematic soils and the impacts of frequent natural disasters like severe flood, cyclone, heavy rainfall and drought. [Md Harunor Rashid Khan]
