1. Phosphorus Cycle
정리: 이지은, 최유진, 이도원

2. 물질 순환 요약 Atmosphere CO2 H2O N2 N2O Plant Leaves, Wood, Roots
Soil Soil water, Mineral N, P
Organic Matter Litter: Leafy, Woody Soil: Active (microbial) Slow (humic) Passive(inert)
C Cycle
Water Cycle
N, P Cycle
Rain
N fixation, N deposition, gaseous N loss
Fertilizer Inputs
Transpiration
Photosynthesis
Leaching
Runoff
Sediment transport
Product offtake
Water flow
C flow
N flow
P flow
Respiration
Raupach et al. IGBP News Letter 48, Dec

3. Introduction Phosphorus
essential to all forms of life on earth.
has no known toxic effects.
Key component in biomolecules : DNA, ATP,
phospholipids
Environmental concerns associated with P ; Eutrophication
(an increase in the fertility status of natural waters that causes accelerated growth of algae or water plants)

4. ※Eutrophication in freshwater ecosystems (lakes, rivers, and bays)
발생지 ;
in freshwater ecosystems (lakes, rivers, and bays)
원인 ;
[urban wastewater systems, surface runoff, or subsurface groundwater flow] + [P in fertilizer and detergents]
deforestation : erosion in catchment area
제어 ;
the chemical, biological, and physical processes that control soil erosion and P solubility
the transport processes that move all forms of P to and within water bodies

6. Why lakes in Korea are vulnerable to eutrophication
High soil erosion
- large ratio of watershed area to lake surface
- High shoreline development
- Extremly high coefficent of river regime
(하상계수)
- Steep soil slopes
Human interference
- Large number of dikes and dams(1,214)
- intensive fertiliser use
- intensive landuse patterns
자료 : 강호정 교수 강의 노트, 정리 : 공영철

7. Lake Morphology Watershed Watershed Lake Lake
참고 : 강호정 교수 강의 노트, 정리 : 공영철

8. 1. Major Reservoirs of Phosphorus in the Earth
저 장 소 총 인(x 1012 kg)
육 지
토 양 암석
생물군
담수(용존)
해 양
침적토 ,000
용존 무기인
입자상
생물군
자료: Bolin 등 (1983). Paul and Clark (1983) 인용.

9. Key supply of P into ecosystems
Geological process(cf.N -> biological)
Ca5(PO4)3OH + acid  PO43-
(Apatite) (Phosphate)
정리 : 공영철

10. The Global phosphorus cycle
Dust transport 1.0
Land plants
3,000
Mining 12
River flow
Bound
Reactive 2
Internal
cycling 60
Mineral
Rock
10,000
1,000
90,000
Internal cycling
Soils 200,000 2
( 단위 : x 1012g P/yr)
Sediments 4 X 109
자료 : 강호정 교수 강의 노트, 정리 : 공영철

11. Terrestrial P cycle
The main input is weathering of calcium phosphate(e.g., apatite)which
uplifted in a geological process
Root exudates and mycorrhizas speed up the weathering
Biota has a tight coupled P cycle
Tropical soil is often P-limited , not N
( why ? )

12. P availability is low in low pH
Log
Activity of P 온대 열대
Ca3(PO4)2
AlPO4·2H2O 3 7 9
열대에서 P부족이유
열대는 산성토양, 산성에서 P활성도 낮음,
온대지방은 Ph가 5~6으로 P활성도 높음
온도와 수분이 높기에 유기물 분해가 잘되어 유기산이 나타나 산성이 된다.
토양속 Al 에의해 bindin됨으로 식물이 사용이 어렵다
강수량에 의한 leaching으로 P 빠져나간다.

13. 2. Major sources of phosphorus in soils.
a. commercial fertilizer
b. animal manures
c. plant residues, including green manures
d. human, industrial, and domestic wastes
e. native compounds of the element.
Whatisheath/heath.htm

14. Phosphate Fertilizers Consumption ROK and DPRK
단위 : Mt =metric tons
출처 : FOOD AND AGRICULTURE ORGANIZATION OF THE UNITED NATIONS
(공 영철 찾음)

15. 3. Beneficial effects of phosphorus on plants.
a. Cell division and fat and albumin formation.
b. Flowering and fruiting, including seed formation.
c. Crop maturation, in which phosphorus counteracts the effects of excess nitrogen application.
d. Root development, particularly of the lateral and fibrous rootlets.
e. Strength of straw in cereal crops, thus helping to prevent lodging.
f. Improvement of crop quality, especially of forages and of vegetables.

16. 4. Phosphorus cycling in soil
There is good evidence that P is the dominant element controlling C and N immobilization.
Redfield ratio ; 106 C : 16 N : 1 P (Redfield 1958)
106 CO2 +16 NO3- + PO H2O + 18 H+ C106H263O110N16P O2
It is hypothesized that accumulation of C, N, S, and P in SOM is dependent on the P content of the soil parent material (Walker 1965).

17. 레드필드비(Redfield ratio, CNP ratio)
식물플랑크톤 안에서 주요 원소의 수가 특색 있는 원자비 (C : N : P=106 : 16 : 1)로 존재하는데, 이 비를 레드필드비라 한다. 플랑크톤 자제뿐만 아니라 심해수에서도 식물플랑크톤 저하작용(degradation)다음의 이들 영양원소들은 이 비율로 녹아 있는 상태에서 발생한다.

20. 표 12.2 캐나다 평원의 3종류 초원토양에서 장기적인 경작에 의해 나타난 인 함량의 변화 Brain lake
표 캐나다 평원의 3종류 초원토양에서
장기적인 경작에 의해 나타난 인 함량의 변화
토양 종류 원산지초원 경작토* 손실(%)
Brain lake
유기탄소(mg g-1)  
총인 (g g-1)  
유기인 (g g-1)  
무기인 (g g-1)   미량
Southerland
유기탄소(mg g-1)  
총인 (g g-1)  
유기인 (g g-1)  
무기인 (g g-1)   미량
Bradwell
유기탄소(mg g-1)  
총인 (g g-1)  
유기인 (g g-1)  
무기인 (g g-1)  
자료: Tiessen 등 (1982), Paul and Clark (1989).
*세 지역에서 경작기간은 각각 90, 75, 60년이었다.

21. 표 12-3. 생물과 토양 유기물에서 탄소:질소:인(C:N:P) 비
해양조류
토양 세균
초원의 토양
미개간지
경작지, 시비된 토양
약간 풍화된 토양
상당히 풍화된 토양

22. ※인의 이용
식물은 PO4 이온의 형태로 흡수
그러므로 org-P는 미생물에 의해서 먼저 분해되어 무기화되어야 함.
PO4- 는 soil solution에 녹아 plant root나 available pool로 감

23. Mycorrhizas(Fungi with Root)
Plant root(host)-Fungi(mycobiont) association
types : Endomycorrhizas(inside) Ectomycorrhizas(outside)
P,N,Water C
Mycorrhiza
Other pathogens
자료 : 강호정 교수 강의 노트, 정리 공영철

25. 5. Inorganic Forms available phosphorus labile phosphorus
The portion of total in soil that is extractable by dilute acid or bicarbonate
it is considered to be the amount of soil P available for uptake by living organisms.
labile phosphorus
The portion of adsorbed P that will be readily available for plant uptake and can be easily extracted and measure, along with soluble P, by a chemical soil test (Pierzynski et al. 1994).
The portion that is resin extractable is the fraction of labile soil P that can enter solution by ionic exchange during a given time span.

26. 6. Desorption and solubilization of inorganic phosphorus
Desorption ; the release of P from the solid phase into the solution phase.
Desorption occurs in soils
when plant uptake depletes soluble P concentrations to very low levels,
or in aquatic systems
when sediment-bound P interacts with natural waters with low P concentrations.
Only a small fraction of adsorbed P in most soils is readily desorbable
Soil organisms and plant roots participate in
the solubilization of soil phosphorus, mainly through their production of CO2
and organic acids

27. 7. Adsorption and precipitation
the removal of ionic P from solution
by a chemical reaction with the solid phase of the soil.
The primary reactive phases in soils and sediments responsible for adsorption reactions are clays, oxides or hydroxides of Fe and Al, calcium carbonates, and organic matter.
Precipitation
the formation of discrete, insoluble compounds in soils

28. 7. Adsorption and precipitation
Equilibrium-based P-adsorption
- Clay and organic matter have adsorption sites on the surface
Ca 2+, Mg2+, Al3+,Fe can strongly bind to P
Measurement ; Sorption isotherm
P max
토양흡착량
여러농도의
P-Solution에
Soil을 넣어 물에
남은 양을 측정
P in water

29. 7. Adsorption and precipitation
In general, soils that are
low in P, acidic,
and high in clay or Fe and Al oxides
- particularly noncrystalline oxides –
have the greatest P adsorption capacities.
In calcareous soils, where the pH is high and soluble Ca is the dominant cation,
CaCO3 and Fe oxides are the dominant factors controlling P adsorption
(Pierzynski et al. 1994).

30. which with time slowly reverts to other more stable Ca phosphates
The addition of soluble P initially results in the formation of dicalcium phosphate dihydrate (CaHPO4·2H2O),
which with time slowly reverts to
other more stable Ca phosphates
such as octacalciumphosphate(Ca8H2(PO4)6·5H2O), and in the long term to apatite [Ca10(PO4)6F2]

31. 8. Organic Phosphorus 표 4. 북미 초원지역 표층 10 cm 에서 총인과 유기인 지 역
지 역
인 함량 ( g P/g soil)
총 합 유기인
Cottonwood, South Dakota
Bridger, Montana
Osage, Kansas
Ale, Washington
Jornado, New Mexico
Pantax, Texas
Bison, Montana
Pawnee, Colorado

32. 9. Mineralization and immobilization
the microbially mediated decomposition of organic compounds, resulting in
the release of inorganic forms of nutrients into the soil solution.
Immobilization
the 'tie-up' of mineral elements such as P by soil microorganisms into biochemical compounds essential for microbial metabolism.
the conversion of organic P to inorganic P

34. 9. Mineralization and immobilization
usually occurs rapidly if the C:P ratio of the organic matter is <200:1
immobilization
the incorporation of P into microbial biomass - occurs if C:P ratios are >300:1 (Pierzynski et al. 1994).

35. 10. Net rate measurements with inhibitors
Blocked by autoclaving
mineralization
net dissolution
Sorbed Inorganic P
Organic P
Solution P
immobilization
precipitation
Blocked by irradiation or autoclaving
Stark 2000, p.220

36. 10. Net rate measurements with inhibitors
Inhibitors that are less than 100% effective or that have unintended side effects on other processes can result in erroneous rate estimates unless corrections can be made (Stark 2000).

37. 11. Phosphorus transport in the environment
Transport of soil P occurs primarily via surface flow, although the background levels of P entering streams and lakes via subsurface flow certainly reflect the impacts of land use.
Direct discharge of P from wastewater treatment systems into rivers represents a distinctly different form of transport that requires enormous technological and economic costs to reduce P effects on the aquatic environment.

38. 12.Practical Control of Phosphrous in Soils
1. Patterning fertilizer rates to fit
soil phosphrous status
2. Placement of phosphorus
3. Combination of ammonium and phosphorus fertilizers
4. Cycling of organic matter
5. Control of soil pH
6. Enhancement of mycorrhizal symbiosis
7. Choice of phosphorus-efficent plants
8. Reduction of runoff and sediment losses,
especially from fertilized and manured land
9. Capturing excess phosphrous
before it enters mainstream channels