Soil Biota
What are the important biological micro & macrobiota of the soil?
Observe the diagram... give me several examplea of organisms that alter soil structure and the significance of their actions....
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fragmentation/degradation of tissues,
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ion modification,
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aggregation,
- water holding capacity?
How do theses creatures alter the soil? in terms of
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Carbon
dioxide can stem soil erosion, study shows: Thursday, August 12, 1999
By Reuters Scientists have unearthed a new clue in the search for ways to combat soil erosion, the science journal Nature reported Wednesday....Matthias Rillig from the Carnegie Institution of Washington in California found that atmospheric carbon dioxide helped bind soil particles together. A healthy soil has many small particles which are structured into clumps called aggregates. These aggregates provide a myriad of tiny caves and cracks that help hold nutrients, water, and organic matter. "Soil aggregation is important for preventing soil loss through wind and water erosion," Rillig wrote in Nature. "Our finding that an increase in soil aggregation could be brought about by atmospheric change may have implications for studies of soil stabilization in ecosystems," he added. Rillig and his team of researchers also found that carbon dioxide can affect soil's fertility. The researchers examined soils from two ecosystems and exposed them to a range of different carbon dioxide concentrations for three to six years. They found that carbon dioxide appeared to stimulate changes in soil structure, leading to an increased abundance, stability, or size of aggregates. A fungus that forms symbiotic relationships with plants seemed to be instrumental in the process, they said. Increased carbon dioxide often leads to increased photosynthesis. Some of the extra carbohydrate produced by this is transferred to the fungi, which in turn provide the plants with nutrients. Using some of the extra carbohydrate, the fungi produce more of a protein-sugar complex called glomalin, which appears to play a critical role in producing and stabilizing soil aggregates. "We think the fungi may use glomalin as a kind of lubricant, allowing them to extend their hyphae &emdash; a root-like filament structure &emdash; through the soil. But it also appears to act as a kind of glue, holding particles together," said Christopher Field, one of the research team. |
Water dynamics ...........Soil life..................Profile of the soil............Soil particle size & effects
...............soil pH.....ecosystesm soils........introduction
