Phosphorus in the global environment
- 2.6k Downloads
Phosphorus is not one of the “global” elements, it does not enter the atmosphere like nitrogen, it does not spread like sulfur by acid rain and its solubility in water is so low that there is only a slow, steady movement of P down-stream as landscapes erode and weather, or P-containing pollutants are discharged. Yet, there are some global trends in the distribution of P. To understand these and their drivers it is useful to review some of the basic properties of P in the environment.
The earth’s crust contains about 1,200 mg P kg−1, making it the 11th most abundant element. Common concentrations for total P in soils are between 200 and 800 mg kg−1, with older soils containing lower amounts of P and younger soils containing higher amounts of P. In primary rocks and young soils, P is largely bound to calcium or magnesium, giving P a typical water solubility near 0.5 mg P L−1. The weathering of minerals changes the solubility of P, as Ca is preferentially leached out, the relative abundance of Fe and Al increases and the solubility of P becomes controlled by Fe- or Al-phosphates, which have much lower solubilities than Ca-phosphates. As a result, the sequestration of P in low-solubility Fe and Al-phosphate compounds and the effect of leaching and erosion, many older and tropical soils are P deficient, i.e. the availability of P to plants and other organisms restricts ecosystem processes such as N fixation or C sequestration.
The availability of P to plants is controlled by physical and chemical reactions, including sorption/desorption and precipitation/dissolution and biological processes such as immobilization (uptake by plants and microorganisms) and by mineralization (decomposition of residues). The sorption of P, followed by slower transformations, such as solid state diffusion into the matrix of the sorbent, reduce the solubility of P, sometimes to such a degree that P is said to become “fixed”. Strictly speaking, P fixation is a misnomer, since all chemical reactions are to some degree reversible, but the amount and rate of release of “fixed” P may be so low that they are ecologically insignificant.
KeywordsGlobal Environment Tropical Soil Young Soil Inositol Hexaphosphate Soil Organic Phosphorus
Unable to display preview. Download preview PDF.
- Anderson NJ (1997) Reconstructing historical phosphorus concentrations in rural lakes using diatom models. In: Tunney H, Carton OT, Brookes PC, Johnston AE (eds), Phosphorus Loss from Soil to Water. CAB International, Wallingford, pp 95–118Google Scholar
- Beaton JD, Roberts TL, Halstead EH, Cowell LE (1995) Global transfers of P in fertilizer materials and agricultural commodities. In: Tiessen H (ed), Phosphorus in the Global Environment: Transfers, Cycles and Management SCOPE 54. Wiley, Chichester, pp 7–26Google Scholar
- Caraco NF (1995) Influence of human populations on phosphorus transfers to aquatic systems: a regional case study using large rivers. In: Tiessen H (ed), Phosphorus in the Global Environment: Transfers, Cycles and Management SCOPE 54. Wiley, Chichester, pp 235–244Google Scholar
- Frossard E, Condron LM, Oberson A, Sinaj S, Fardeau JC (2000) Processes governing phosphorus availability in temperate soils. J Environ Qual 29: 15–23Google Scholar
- Hanway JJ, Olsen RA (1980) Phosphate nutrition of corn, soya beans, and small grains. In: Khasawneh FE, Sample EC, Kamprath EJ (eds), The Role of Phosphorus in Agriculture. ASA/CSSA/SSSA, Madison, WI, pp 681–692Google Scholar
- Harrison AF (1987) Soil Organic Phosphorus - A Review of World Literature. CAB International, WallingfordGoogle Scholar
- Howarth RH, Jensen HS, Mariano R, Postma H (1995) Transport to and processing of P in near-shore and oceanic waters. In: Tiessen H (ed), Phosphorus in the Global Environment: Transfers, Cycles and Management SCOPE 54. Wiley, Chichester, pp 321–345Google Scholar
- Melak JM (1995) Transport and transformations of P, fluvial and lacustrine ecosystems. In: Tiessen H (ed), Phosphorus in the Global Environment: Transfers, Cycles and Management SCOPE 54. Wiley, Chichester, pp 245–254Google Scholar
- Menezes RSC, Sampaio EVSB (2002) Simulação dos fluxos e balanços de fósforo em uma unidade de produção agrícola familiar no semi-árido paraibano. In: Silveira LM, Petersen P, Sabourin E (eds), Agricultura familiar e agroecologia no semi-árido: avanços a partir do Agreste da Paraíba. Rio de Janeiro, RJ, pp 249–260Google Scholar
- Pritchett WL, Fisher RF (1987) Nutrient cycling in forest ecosystems. In: Properties and Management of Forest Soils (2nd edition). Wiley, New York, pp 180–204Google Scholar
- Rodriguez-Jimenez LVA (1988) Consideraciones sobre la biomasa, composicion quimica y dinamica del bosque pluvial tropical de colinas bajas, Bajo Calima, Buenaventura, Colombia. In: Serie Documentacion, Corporacion Nacional de Investigacion y Fomento Forestal. Bogota, ColombiaGoogle Scholar
- Sharpley AN, Rekolainen S (1997) Phosphorus in agriculture and its environmental implications. In: Tunney H, Carton OT, Brookes PC, Johnston AE (eds), Phosphorus Loss from Soil to Water. CAB International, Wallingford, pp 1–54Google Scholar