NRES 201 Lecture 30 Outline of Last Lecture I Fundamentals of liming II Neutralizing value of a liming material III Liming Calculations IV Common liming materials V Soil acidification VI Salt affected soils Outline of Current Lecture I The diversity of soil organisms II The food web III Organism abundance and metabolic activity Current Lecture The diversity of soil organisms Types of organisms Animals v plants o Fauna animals o Flora plants non animal microbes Domains o Eukarya plants animals and fungi o Bacteria and Archaea microbes Food Source Carbon and other sources o Heterotrophs use organic compounds o Autotrophs use CO2 for carbon energy from photosynthesis or chemical oxidation Diversity and Isolation Species diversity vastly greater for soils than for aquatic environments owing to a nearly limitless food variety and a much wider range of habitat conditions Soil aggregates isolate meso and microorganisms Importance of Diversity The presence of more species increases o Functional diversity A wider variety of substrates can be used to carry out a wider array of processes These notes represent a detailed interpretation of the professor s lecture GradeBuddy is best used as a supplement to your own notes not as a substitute o Functional redundancy A given process occurs under a wider range of environmental conditions Benefits of biological diversity o For soil quality ecosystem stability and resilience o Soil processes remain active and recover from disturbance Implications for global biodiversity Soil is a major storehouse of genetic information because so many species live underground Mankind has learned to utilize some of this information in making antibiotics yogurt and beer The soil DNA bank is as valuable resource for genetic engineering o Microbial genes utilized for plant or animal improvement Ecosystem Engineers Some organisms create new habitats for others by altering their environment Organism abundance and metabolic activity Populations and biomass o Controlled by food supply physical factors biotic factors and chemical factors Generalizations o Greater fauna diversity in forest soils o Greater faunal mass and activity in prairie soils o Soil tillage reduces faunal numbers mass and activity Comparison of different organisms Basis of comparison per unit volume or area o Number of individuals o Their collective weight biomass o Their metabolic activity CO2 production Microflora are dominant o Bacteria most numerous o Fungi produce the most biomass o Account for about 80 of total soil metabolism
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