Chapter 22: Decomposition & Nutrient Cycling
A generalized model of nutrient cycling
•Retranslocation or reabsorption nutrients.........
•Decomposing organisms are categorized into groups based on size and function
–Microflora: bacteria and fungi
•Microfauna and microflora
•Bacteria are the dominant decomposers of dead
•Fungi are the major decomposers of plant matter
Results of a litterbag experiment in central Virginia.
Looks at decomposition of fallen leaves.
Organic matter decomposes at different rates
• The carbon form available affects the consumption (or decomposition) rates:
–Cellulose and hemicellulose
C9H10O2, C10H12O3, C11H14O4
•An experiment that studied rate of carbon decay in straw found the following........
Variation in rates of decay of different classes of carbon compounds
Nutrients in Organic Matter Are Mineralized During Decomposition
•If the nitrogen content of the litter material is high, then mineralization may exceed the rate of immobilization from the onset of decomposition