Phosphorus Cycle 정리: 이지은, 최유진, 이도원

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. 2001.

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)

※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

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

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

1. Major Reservoirs of Phosphorus in the Earth 저 장 소 총 인(x 1012 kg) 육 지 토 양 96 - 160 암석 19 생물군 2.6 담수(용존) 0.090 해 양 침적토 840,000 용존 무기인 80 입자상 0.65 생물군 0.050 - 0.12 자료: Bolin 등 (1983). Paul and Clark (1983) 인용.

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

The Global phosphorus cycle Dust transport 1.0 Land plants 3,000 Mining 12 River flow Bound 19 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

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 ? )

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.

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. http://www.anr.state.vt.us/champ/phospsum.htm http://www.aekyung.co.kr/ http://www.anr.state.vt.us/champ/phospsum.htm www.ma.adfa.edu.au/Research/Heathland/ Whatisheath/heath.htm

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

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.

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- + PO43- + 122 H2O + 18 H+ C106H263O110N16P + 138 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).

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.

표 12.2 캐나다 평원의 3종류 초원토양에서 장기적인 경작에 의해 나타난 인 함량의 변화 Brain lake 표 12.2 캐나다 평원의 3종류 초원토양에서 장기적인 경작에 의해 나타난 인 함량의 변화 토양 종류 원산지초원 경작토* 손실(%) Brain lake 유기탄소(mg g-1) 47.9  10.2 32.8  5.2 32 총인 (g g-1) 823  92 724  53 12 유기인 (g g-1) 645  125 528  54 18 무기인 (g g-1) 178  47 196  8 미량 Southerland 유기탄소(mg g-1) 37.7  6.5 23.7  1.8 37 총인 (g g-1) 756  28 661  31 12 유기인 (g g-1) 492  5.2 407  30 17 무기인 (g g-1) 256  44 254  19 미량 Bradwell 유기탄소(mg g-1) 32.2  8 17.4  1.6 46 총인 (g g-1) 746  101 527  15 29 유기인 (g g-1) 446  46 315  21 29 무기인 (g g-1) 300  84 212  46 29 자료: Tiessen 등 (1982), Paul and Clark (1989). *세 지역에서 경작기간은 각각 90, 75, 60년이었다.

표 12-3. 생물과 토양 유기물에서 탄소:질소:인(C:N:P) 비 해양조류 106 16 1 토양 세균 31 5 1 초원의 토양 미개간지 191 6 1 경작지, 시비된 토양 119 9 1 약간 풍화된 토양 80 5 1 상당히 풍화된 토양 200 10

※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

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

http://muextension.missouri.edu/xplor/agguides/soils/g09180.htm http://www.efma.org/publications/

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.

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

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

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

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).

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] http://www.westernlaboratories.com/instructions/workingwithsoilreports/Phosphorus.html

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 554 310 Bridger, Montana 1234 675 Osage, Kansas 251 227 Ale, Washington 748 29 Jornado, New Mexico 445 37 Pantax, Texas 239 94 Bison, Montana 835 582 Pawnee, Colorado 345 131

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

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).

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

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).

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.

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