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The soil is home to a large proportion of the world's biodiversity.The links between soil organisms and soil functions are complex. The interconnectedness and complexity of this soil 'food web' means any appraisal of soil function must necessarily take into account interactions with the living communities that exist within the soil.
Soil mesofauna do not have the ability to reshape the soil and, therefore, are forced to use the existing pore space in soil, cavities, or channels for locomotion. Soil Macrofauna, earthworms, termites, ants, and some insect larvae, can make the pore spaces and hence can change the soil porosity, [5] one aspect of soil morphology. Mesofauna ...
They sequester nitrogen and other nutrients that might otherwise enter groundwater, and they fix nitrogen from the atmosphere, making it available to plants. Many organisms enhance soil aggregation and porosity, thus increasing infiltration and reducing surface runoff. Soil organisms prey on crop pests and are food for above-ground animals.
A diazotroph is a microorganism that is able to grow without external sources of fixed nitrogen. Examples of organisms that do this are rhizobia and Frankia and Azospirillum. All diazotrophs contain iron-molybdenum or iron-vanadium nitrogenase systems. Two of the most studied systems are those of Klebsiella pneumoniae and Azotobacter vinelandii ...
Biological soil crusts are most often [3] composed of fungi, lichens, cyanobacteria, bryophytes, and algae in varying proportions. These organisms live in intimate association in the uppermost few millimeters of the soil surface, and are the biological basis for the formation of soil crusts.
Soil erosion occurs naturally, but human activities can greatly increase its severity. [28] Soil that is healthy is fertile and productive. [29] But soil erosion leads to a loss of topsoil, organic matter, and nutrients; it breaks down soil structure and decreases water storage capacity, reducing fertility and water availability to plant roots.
Fungi are abundant in soil, but bacteria are more abundant. Fungi are important in the soil as food sources for other, larger organisms, pathogens, beneficial symbiotic relationships with plants or other organisms and soil health. Fungi can be split into species based primarily on the size, shape and color of their reproductive spores, which ...
It is a general feature of all higher and many lower plants as well as other organisms. Charles Darwin was one of the first to scientifically document that roots show positive gravitropism and stems show negative gravitropism . [ 1 ]