Phosphorus available in soil

Oehl F, Oberson A, Tagmann HU, Besson JM, Dubois D, Mader P, Roth HR, Frossard E (2002) Phosphorus budget and phosphorus availability in soils under organic and conventional farming. Nutr Cycl Agroecosyst 62 25-35... 

Phosphorus availability in soils is regulated by pH. The relationship between phosphorus solubility and pH is shown in Figure 9.20. In the hgure, the y-axis represents the concentration of phosphate... 

H Keith, R. J. Raison, and K. L. Jacobson, Allocation of carbon in a mature eucalypt forest and some effects of soil phosphorus availability. Plant Soil 796 81 (1997). 

Bucher S. 2001. Nitrogen and phosphorus availability in irrigated rice as influenced by soil drying during the fallow period, straw incorporation, and tillage. PhD thesis, ETH-Zilrich. 

Ammonium polyphosphate is one of the most often used phosphoric fertilizers (Corbridge, 1980). It was found to be equally effective when compared with single superphosphate and diammonium phosphate for increasing the yields of wheat and maize and for increasing the available phosphorus content in soil during field experiments (Sharma and Singh, 1998). 

Sequential extraction or chemical fractionation techniques have been widely used in the characterization of various phosphorus fractions in soils and sediments, with an emphasis on the more bioavailable or plant-available inorganic forms (Condron et al., 2005). Early extraction procedures (Chang and Jackson, 1957 Williams et al., 1976b) focused on inorganic phosphorus associated with iron, aluminium and calcium, using various acid, base or salt extraction steps. Organic phosphorus was considered to be the residual or refractory phosphorus-containing fraction that remained after all other extractions had been performed. 

Organic phosphorus as a widely available phosphorus source in soil... 

Campo, J., Jaramillo, V.J. and Maass, J.M. (1998) Pulses of soil phosphorus availability in a Mexican tropical dry forest effects of seasonality and level of wetting. Oecologia 11 5, 1 67-1 72. 

Richardson, A.E. (1994) Soil microorganisms and phosphorus availability. In Pankhurst, C.E., Doube, E.M., Gupta, V.V.S.R. and Grace, P.R. (eds) Soil Biota Management in Sustainable Farming Systems. CSIRO Publishing, East Melbourne, pp. 50-52. 

Scharer, M. (2003) Processes controlling phosphorus availability in two grassland soils. PhD thesis, Swiss Federal Institute of Technology, Zurich. 

Walbridge, M.R. (1991) Phosphorus availability in acid organic soils of the lower North-Carolina coastal-plain. Ecology 72, 2083-2100. 

Frossard, E., Condron, L.M., Oberson, A., Sinaj, S. and Fardeau, J.C. (2000) Processes governing phosphorus availability in temperate soils. Journal of Environmental Quality 29, 1 5-23. 

McGrath, D.A., Comerford, N.B. and Duryea, M.L. (2000) Litter dynamics and monthly fluctuations in soil phosphorus availability in an Amazonian agroforest. Forest Ecology and Management 131, 167-181. 

Huffman, S.A. (1995) Phosphorus solubility and availability in soils formed under different weathering regimes. PhD thesis, Colorado State University, Fort Collins, Colorado. 

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