Presentation prepared as a part of my M. Sc. Ag. Agroforestry assigment topic

1. BANARAS HINDU UNIVERSITY,UP
RAJIV GANDHI SOUTH CAMPUS
Submitted to:
Dr. Shashidhar K. S.
FV & AS, RGSC
BHU, Barkachha
Submitted by:
Nalini
M.Sc.(Ag) Agroforestry
Roll no. 20430AGF015
Department of Agroforestry
BIOGEOCHEMICAL CYCLING OF NUTRIENTS
SWC-502(Soil and Water Management in Agroforestry)
Biogeochemical Cycle

2. content
General introduction
Types of biogeochemical cycle
Gaseous Nutrient Cycle- C,O,N cycle
Sedimentary Nutrient Cycle-S,P cycle
References
Biogeochemical Cycle

3. BIOGEOCHEMICAL CYCLING OF NUTRIENTS
 Nutrient and water are essential for ecosystem to
continue functioning.
 Living organism need 30-40 elements for normal
development.
 The chemical elements or nutrients flow from the
nonliving to the living and back to the nonliving
components of the ecosystem in a more or less cycling
path.
Biogeochemical cycles

4.  Nutrients that are required by organism, primary
autotrophs, may be classified into:
1. Macro nutrients- are required in relatively large amount
and they include:
 Carbon, Hydrogen, Oxygen, Nitrogen, Potassium,
Calcium, Magnesium, Sulfur and Phosphorus.
2. Micro nutrients- are required in small quantities, among
the are:
 Iron, Manganese, Copper, Zinc, Sodium and so on
 These nutrients have to cycle in ecosystem depend on
the supply and circulation of these nutrients.
Biogeochemical Cycle

5. Biogeochemical cycle have two basic types:
1. Gaseous Nutrient Cycle- the main source of nutrient
are the atmosphere and the oceans.
 The gas which are most important for life are nitrogen,
oxygen and carbon dioxide.
 These three gases in stable quantities of 78%, 21% and
0.03%, respectively
Example: Nitrogen, Oxygen and Carbon Cycles
Biogeochemical cycle

6. 2. Sedimentary Nutrient Cycle- the main source are soil,
rocks and minerals.
 The mineral elements that living organisms require come
initially from inorganic sources.
 Mineral salts come directly from the Earth’s crust through
weathering
Example: Sulfur Cycle, Phosphorus Cycle
 Both Gaseous and Sedimentary Nutrient Cycles involve
biological and non biological processes.
 Both are driven by the flow of energy through the
ecosystem.
 Both are tied to Water/Hydrologic Cycle
Biogeochemical cycles

7. Biogeochemical Cycles

8. • Carbon is the basic building block element of large
molecules necessary for life.
 The source of carbon for plants is the carbon dioxide in
the atmosphere and dissolved carbon dioxide in water.
 Carbon also occurs in the earth’s crust as carbonate
rocks such as limestone.
 Volcanos can return carbon dioxide to the air and water
during eruptions.
 The carbon is converted from carbon dioxide into sugars
by green plants and into organic molecules by
photosynthesis
 From there the carbon is transferred through ingestion
along the food chains to herbivores and carnivores
Biogeochemical Cycles

9.  At each stage part of the carbon stored in the complex
food molecules is broken down through respiration to
release energy and carbon is cycled back as carbon
dioxide to the air and water.
 The remaining carbon is returned to the air and water
when an organisms die and decay
Biogeochemical Cycle

10. Biogeochemical Cycle
OXYGEN CYCLE

11. • It is the most important element of the human body,
makes up about 65% of the mass of the human body
• The three main reservoirs are the air, ecosystems and
Earth’s crust
• The main driving factor of the oxygen cycle is the
process of photosynthesis
• The oxygen cycle is interconnected with the carbon
dioxide
 The autotrophs uses carbon dioxide, water and sunlight
to produce food and releases oxygen to the atmosphere
 The animals then breathe in the oxygen and breathe out
carbon dioxide that is needed again by the plants in
manufacturing food
 Decaying matters release carbon dioxide that also used
by the plants for photosynthetic process
Biogeochemical Cycle

12. Biogeochemical Cycle

13. Biogeochemical Cycle

14. • Nitrogen is an important element because it is a
constituent of some biological molecules.
 Most of the nitrogen in living organisms does not enter
directly from the atmosphere. Instead, the nitrogen fixing
bacteria in the soil, algae in water and in roots of
leguminous plants converted the gaseous nitrogen into
nitrates, some are fixed by lightning.
 These nitrate salts dissolve in soil water and are
absorbed by plants and converted into nucleic acids and
proteins.
 When animals (herbivores) feed on these plants, some
nitrogen is passed to the animals and eventually to
other animals (carnivores)
Biogeochemical Cycle

15. Biogeochemical Cycle

16.  When the organisms die their nitrogen is converted to
ammonia gas and soluble ammonium salts by
saprotrophic fungi and bacteria.
 These are converted by nitrifying bacteria either into
nitrite the to nitrate.
 Plants can absorb the dissolved ammonium or the nitrate
to begin the nitrogen cycle again.
 Some of the nitrate is converted to nitrogen by
denitrification of bacteria.
Biogeochemical Cycle

17. Nitrogen Cycle Four Special Processes involved in the
Nitrogen Cycle:
1. Nitrogen fixation-
 Atmospheric nitrogen is converted to nitrates.
 Accomplished physio-chemically and by nitro- fixing
bacteria
2. Aminification-
 Nitrates are converted to ammonia and ammonia
compounds.
 Accomplished by bacteria and fungus of decay
Biogeochemical Cycle

18. Four Special Processes involved in the Nitrogen
Cycle:
3. Nitrification-
 Ammonia compounds and ammonia are converted to
nitrates
 Accomplished by nitrite and nitrate bacteria
4. Denitrification-
 Nitrates are converted to atmospheric nitrogen
 Accomplished by denitrifying bacteria
Biogeochemical Cycle

19. Biogeochemical Cycle

20. Biogeochemical Cycle

21. • Sulfur has both gaseous and sedimentary phases
• Sedimentary sulfur comes from the weathering of rocks,
runoff and decomposition of organic matter
• Gaseous sulfur are from decomposition of organic matter,
evaporation of oceans and volcanic eruptions
 A significant portion of the sulfur released to the
atmosphere is a by-product of the burning of fossil fuels
 Sulfur enters the atmosphere mostly as hydrogen
sulfide, which quickly oxidizes to sulfur dioxide
 Sulfur dioxide reacts with moisture in the atmosphere to
form sulfuric acid, carried to Earth in precipitation
 Plants incorporate it into sulfur-bearing amino acids
 Consumption, excretion and death carry sulfur back to
soil and aquatic sediments, where bacteria release it in
inorganic form
Biogeochemical Cycle

22. Biogeochemical Cycle

23. Biogeochemical Cycle

24. • In living organisms phosphorus is an important
component of nucleic acids, cell membranes, teeth and
bones
• This cycle is interesting because unlike the previous
cycles, it lacks an atmospheric component
• The major reservoir is sedimentary rock in the earth’s
crust
 Phosphorus is absorbed by plants from the soil as
dihydrogenphosphate or hydrogenphosphate
 t is then passed to animals, that is, herbivores and then
carnivores.
 t is eventually returned to the soil, rivers and oceans as
animal excretion or through decomposition after death
Biogeochemical Cycle

25. Biogeochemical Cycle

26. Biogeochemical Cycles are Linked
 The nutrients that cycle are all components of living
organisms, constituents of organic matter
 The stoichiometric relationships among various elements
involved in plant processes related to carbon uptake and
plant growth have an important influence on the cycling
of nutrients in ecosystems
 Interconnection of different biogeochemical cycles may
always lead to equilibrium state within the biosphere
Biogeochemical Cycle

27. REFRENCE
 "Biogeochemical Cycles". The Environmental Literacy
Council. Retrieved 20 November 2017.
 Jump up to: Baedke, Steve J.; Fichter, Lynn
S. "Biogeochemical Cycles: Carbon Cycle". Supplimental
Lecture Notes for Geol 398. James Madison University.
 Organic contaminants that leave traces : sources, transport
and fate. Ifremer. pp. 22–23.
 McGuire, 1A. D.; Lukina, N. V. (2007). "Biogeochemical
cycles" (PDF). In Groisman, P.; Bartalev, S. A.; NEESPI
Science Plan Development Team (eds.). Northern Eurasia
earth science partnership initiative (NEESPI), Science plan
overview. Global Planetary Change. 56. pp. 215–234.
 "Distributed Active Archive Center for Biogeochemical
Dynamics". daac.ornl.gov. Oak Ridge National Laboratory.
Retrieved 20 November 2017.

28. Biogeochemical Cycle