The process of the degradation of organic material in the soil and the microbes that perform these processes DISCUSSION:
85% dead matter 10% roots of living plants 5% microbes soil & animals SOIL organisms that degrade materials: microbes/ ants/ worms Ants/ beetles/ microarthropods Composition of SOIL is:
1. Structures easy to decompose ie:sugars/starch/protein 2 . 10 weeks - leaves decompose cellulose (insoluble carbohydrate of plants) 30 weeks: stem material thinner lignan (complex structure of wood) 3 . 10 years – waxes/ phenols/ lignan 4. HUMUS - result of compounds that resist decomposition and have accumulated in soil (Soil Health, 2008)
DEGRADATION is a series of steps that: break the molecular structure of the organic matter into smaller & smaller components . THEN: mineral nutrients are released to the soil
1. chemical alteration occurs 2. physical fragmentation 3. release of mineral nutrients 3 steps in degradation of organic matter (Soil Health, 2008)
ESPECIALLY common microbe in SOIL – Actinomyces, (genus) <ul><li>SOME strictly DON’T utilise O 2 </li></ul><ul><li>OTHERS can utilise O 2 OR chemicals </li></ul>this MICROBE produces an enzyme – geosmin , this is the distinct smell given to TOPSOIL tolerates dry conditions when other microbes can’t
THESE minerals in soil aid the microbes metabolism ; by enabling the transfer of electrons within the reactions that occur (Soil Health, 2008)
Type & amount of organic matter Their ability to ADAPT depends upon: POROSITY NUTRIENTS pH 6.0-8.0 TEMPERATURE 15-30 o C contaminants AVAILABLE O 2 (Texas A and M University, 2008)
Other common Microbes in soil: Bacillus (genus) SUBTILIS Actinomycete (genus) STREPTOMYCES Clostridium (genus) PERFRINGENS
MICROBES can quickly adapt & reach high densities within soil <ul><li>ORGANIC MATTER is degraded by: </li></ul><ul><li>lack of replenishment </li></ul><ul><li>action of microbes </li></ul>(Wikipedia, 2008)
Bibliography Soil Health. (2008). Soil organic matter . Retrieved September 21, 2008, from http//:www. soil health.com/ organic - Texas A and M University. (2008). Welcome to soil and crop sciences at Texas A and M University. Retrieved September 20, 2008, from http//: www.organiclifestyles.tamu.edu/ soil / microbe index.html - 32k - Wikipedia. (2008). Soil life . Soil life – wikipedia, the free encylopedia. Retrieved September 24, 2008, from http//:en.wikipedia.org/wiki / Soil _life - 35k -
A particular slide catching your eye?
Clipping is a handy way to collect important slides you want to go back to later.