Assessing alternative approaches to prediting soil phosphorus sorption
Burkitt, LL and Gourley, CJP and Hannah, MC and Sale, PWG (2006) Assessing alternative approaches to prediting soil phosphorus sorption. Soil Use and Management, 22 . pp. 325-333.
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Twenty-five pasture soils were sampled from high-rainfall zones of southeastern Australia to examine
relationships between soil properties, and between soil properties and P buffering capacity (PBC) measures.
Correlations between PBC values and soil properties were generally poor, with the exception of
oxalate-extractable Al (Al [subscript]ox) (r greater than or equal to 0.97). Predictions of PBC were further improved when clay, as well
as Alox, was included in a linear regression model (r2 greater than or equal to0.98). When Alox and oxalate-extractable Fe
were excluded from the modelling exercise, a more complex three-term linear regression model, including
pH [subscript]H2O, exchangeable H and cation exchange capacity, adequately fitted both PBC values of the
25 soils examined in this study (r2 greater than or equal to0.76). However, the Alox, Alox plus clay and the three-term models
gave poor predictions of the PBC values when the models were validated using 28 independent
soils. These results emphasize the importance of model validation, because predictive models based on
soil properties were not robust when tested across a broader range of soil types. In comparison, direct
measures of PBC, such as single-point P sorption measures, are more practical and robust methods of
estimating PBC for Australian soils.
|Keywords:||Phosphorus, sorption, buffering, soil properties, models, single-point phosphorus sorption|
|Deposited By:||Dr Lucy Burkitt|
|Deposited On:||05 Jan 2007|
|Last Modified:||18 Jul 2008 19:45|
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