NREM 301 Forest Ecology & Soils Day 25 November 17, Nutrient Cycling Lab Field Quiz/Exercise Quiz Thursday in class

Transcription

1 NREM 301 Forest Ecology & Soils Day 25 November 17, 2009 Nutrient Cycling Lab Field Quiz/Exercise Quiz Thursday in class

2 Closed Notes - Group Activity On poster paper prepare a Labeled diagram of the N Cycle In the Agricultural landscape of Central Iowa Include each of the following words (phrases) on the diagram 1. Decomposition 2. Nitrification 3. Nitrobactor 4. Assimilation 5. Ammonification 6. Leaching/Drainage Loss 7. Free living bacteria 8. Denitrification 9. Nitrogen Fixation 10. Anaerobic 11. Fertilization 12. Rhizobium 13. Atmospheric deposition 14. Nitrate 15. Nitrosomanos 16. Ammonia/Ammonium 17. Nitrite 18. Organic matter N 19. N 2 gas 20. Mineralization 21. Anaerobic 22. Tiles 23. Surface runoff 24. Symbiotic N fixers 25. Translocation

3 Now Indicate on the diagram the Biochemical Biogeochemical Geochemical Subcycles of the N Cycle Then List the differences in the N cycle that you would expect to see if the area were: A native prairie A conifer forest

4 Fertilization Free Living Bacteria - Azotobactor Symbiotic N-fixers Rhizobium Woody Legumes Frankia Woody Non-legume Lightening Surface Runoff Nitrogen Cycle In a crop field Anaerobic Uptake Nitrobacter Bacteria Ammonium Ammonia (NH 3 ) Ammonium (NH 4 ) Leaching & tiles Nitrosomonas Bacteria Mineralization

5 Leaching & tiles No N from Weathering/All from Atmosphere Fertilization Identify sub-cycles as annual sources Geochemical = 16% Biogeochemical = 45% Surface Runoff Biochemical = 39% Uptake Ammonium Ammonia (NH 3 ) Ammonium (NH 4 )

6 What happens to N Cycle when going from corn to prairie? Uptake Ammonium Ammonia (NH 3 ) Ammonium (NH 4 ) Fixation down/up Plant loss down OM added to soil up Decomposition rate down Ammonification down Nitrification down Denitrification up if no tile Leaching down Plant uptake up Surface runoff down Leaching No N from Weathering/All from Atmosphere

7 What happens to N Cycle when going from corn to forest? Fixation down/up Plant loss down OM added to soil up Decomposition rate down Ammonification down Uptake Ammonium Ammonia (NH 3 ) Ammonium (NH 4 ) Nitrification down/acid Denitrification up if no tile Leaching down Plant uptake up Surface runoff down Leaching No N from Weathering/All from Atmosphere

8 Very Little Atmosphere Addition The P cycle 60% Loss from animal & plant harvest Fertilizer & Manure Addition No Gaseous Loss Erosion P Sorbed To Soil Soil Solution P Weathering Addition Plant Uptake Organic P Decomposition Mineralization Minor Leaching P Sorbed To Soil

9 How does the Phosphorus Cycle differ from the N Cycle? Detergents Includes animal waste Not much atmospheric input Mining Phosphate Rocks Major Loss Minor compared to

10 Note very little P input from the atmosphere

11 Loss with erosion P adsorbed to soil What happens to P cycle?

12 What Happens to P Cycle When - Riparian & Upland Pastures Are Overgrazed? Added from manure Loss with erosion P adsorbed to soil

13 CO 2 All Atmosphere Input PS O 2 & CO 2 RS Carbon Cycle RS Movement Of Sugar Stored as Starch Loss from animal & human eating harvest of plants (lumber, corn, ethanol etc.) C Storage Eating Dying Tree/Plants Major C Storage Sequestration Litter RS Manure Addition Erosion Excreation Soil No Plant Carbon Uptake Humus Carbon Sequestration No Weathering Addition Organic C Storage & Decomposition Very Minor Leaching

14 Atmosphere Carbon Cycle What are the major: Inputs? Sinks? Outputs? Pg. 505 text

15 Carbon Cycle & Photosynthesis Leaf tissue 42% C, 42% O, 8% H; 8% Ash (1-2% N) Where does C come from & how does it get into the plant? What is the function of C in the plant? Photosynthesis & Respiration sort of opposing processes GP = gross photosynthesis RS = respiration NP = net photosynthesis NP = GP - RS NP is equal to Plant Growth It is what we see from Ps

16 Response of NP = GP RS to temperature

17 P 498 text How does seasonal C allocation vary why? Carbon Allocation to Different Parts of the Plant Low numbers high priority What is its role in the survival strategy of the tree?

18 Plant Community (no animals) NPP = GPP RA (respiration of plants) (NPP = net primary production) Ecosystem (plants & animals) NEP = GPP (RA + RH) where RH = respiration of animals (heterotrophs) NEP = Net ecosystem production or Ecosystem Biomass Five major biomass pools in an ecosystem? 1. Above/below-ground biomass 2. Woody debris 3. Forest floor 4. Mineral soil (6 types of OM in soil) 5. Tissues of heterotrophs (animals)

19 What are the largest biomass sinks in different forests? What are the major differences in total biomass production between forests? How much biomass is there in the animal component of the ecosystem?