Abstract
Background and aimsSink extraction of phosphorus from soils has been utilised to study soil P desorption kinetics and as index of plant availability, but not for quantitative prediction of P uptake by plants. Here we investigate the potential of a modified sink extraction method for determining P desorption kinetics and for quantifying plant available soil P.MethodsModified diffusive gradients in thin films samplers were immersed in shaken soil suspensions for long-term extraction of soil P. Results were evaluated in terms of P desorption kinetics and compared to the P uptake of Zea mays L. and standard soil extracts.ResultsIn contrast to literature reports, four of the six studied soils only showed a rapid, but not a slowly desorbing P fraction. The quantity of P desorbed by long-term sink extraction not only showed the highest correlation to plant P uptake, but also matched plant P uptake quantitatively.ConclusionsOur data indicates that soils with only a fast desorbing P fraction might exist. Sink extraction methods have the potential to quantitatively predict plant P uptake. Furthermore, they could become valuable research tools for understanding P acquisition and might serve as a benchmark for calibrating soil P tests.
Highlights
Infinite-sink methods have been proposed as alternatives to chemical extraction procedures for measuring reversibly adsorbed P in soils
Our data indicates that soils with only a fast desorbing P fraction might exist
As the cDGT values cannot be related to an amount of soil from which P is released, they are presented as time-averaged concentrations at the soilsampler interface
Summary
Infinite-sink methods have been proposed as alternatives to chemical extraction procedures for measuring reversibly adsorbed P in soils. In these methods, a phosphate-binding material is introduced, either into a soil suspension or into a soil paste of high water content. The resin binds phosphate and keeps the extractant (or porewater) phosphate concentration very low, shifting the equilibrium between surface-sorbed and dissolved P towards the dissolved phase. Through this process, phosphate is continuously desorbed from soil and captured on the binding material. We investigate the potential of a modified sink extraction method for determining P desorption kinetics and for quantifying plant available soil P
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
