Soil science research has probably underestimated the significance that short-term, episodic cycles ofreduction and oxidation has had on phosphorus (P) reactivity. Here, the effects of eleven pulsedreduction-oxidation (including wet-dry) cycles on soil P dynamics are compared for 12 soils havingcontrasting properties and all overfertilised with respect to P. The laboratory based incubation conditionsattempted to simulate transient waterlogging of the soil profile and involved repeated sampling andanalysis of both the solution and solid phase P forms. An initial increase in P concentration in solutionthat occurred up to and including the fourth full cycle was followed by a sharp decline in concentrationfor all but one soil. Accompanying changes in the main extractable forms of P, which appeared to becumulative, could be summarised as a general decline in the organic P fraction and an overall increase inamorphous associated inorganic forms of P. The fact that up to 60% of the total soil P was demonstrated tochange its sensitivity for a particular extractant suggests that these operationally defined P forms aresusceptible to transformation as a consequence of changing environmental conditions. There was alsoa suggestion that certain of the changes in P forms were irreversible. While the laboratory conditionsimposed do represent extreme conditions the soils only experienced cyclic changes in their moistureregime. If timing and frequency of intense precipitation events are likely to increase, as predicted inmany climate change scenarios, then these results suggest that the effects of episodic redox pulses mayhave implications for P cycling in agricultural soils.
|Numero di pagine||6|
|Rivista||Journal of Environmental Management|
|Stato di pubblicazione||Published - 2012|
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