Diffusive Gradients in Thin-films (DGT), a New Technique in Predicting Soil Bio-availability of Mineral Elements for Plants

Document Type : Research Paper

Authors

1 Associate Professor, Soil Science Department, University of Tabriz, Tabriz. Iran.

2 PhD. Student of Soil Science Department, University of Tabriz,Tabriz, Iran

Abstract

Total concentrations of mineral elements in soil bear little relation to their availability for plants. The DGT (diffusive gradients in thin-films) technique has been found to be a good predictor of trace metals, micronutrients, phosphorous and potassium bio-availability and uptake. In the DGT technique, elements are accumulated on a binding gel after their diffusive transport through a hydrogel. In this review paper, we explore in a more detail why and under which conditions DGT correlates with plant uptake. The theoretical considerations will be illustrated and some of  experimental results in relation to metal uptake and toxicity, phosphorus and potassium will be reported. Strong correlations between DGT and plant uptake are predicted if the diffusive transport of the element from soil to the plant roots is rate-limiting for its uptake.   If uptake is not limited by diffusive transport, DGT-fluxes and plant uptake may still show correlation. Of course, this will be true in the condition which plant uptake is not saturated. However, competitive cations may affect the plant uptake under these conditions, whereas they have no effect on the DGT flux. Moreover, labile complexes are not expected to contribute to the plant uptake if diffusion is not limited, but they are measured with DGT. Therefore, if plant uptake is not limited by diffusion, interpretation of the observed correlation in terms of the labile species measured by DGT is inappropriate.

Keywords

References

  1. Barber S A, 1984. Soil Nutrient Bioavailability: A Mechanistic Approach. Toronto, Canada, John Wiley & Sons.
  2. Bielders C L, Debacker LW and Delvaux B, 1990. Particle density of volcanic soils as measured with a gas pycnometer. Soil Science Society of America Journal. 54: 822- 826.
  3. Benoit G, Rozan TF, 1999. The influence of size distribution on the particle concentration effect and trace metal partitioning in rivers. Geochim. Cosmochim. Acta. 63 (1): 113–127.
  4. Blair G and Lefroy R, 1993. Interpretation of soil tests: a review. Australian Journal of Experimental Agriculture. 33: 1045-1052.
  5. Corey R B and Schulte E E, 1973. Factors affecting the availability of nutrients to plants. In Soil Testing and Plant Analysis. L M Walsh, and Beaton JD. Madison, Wisconsin USA, Soil Science Society of America, Inc. 23-34.
  6. Davison W and Zhang H, 1994. In site speciation measurement of trace components in natural waters using thin film gels. Nature. 367: 546-548.
  7. Gimpel J, Zhang H, Hutchinson W and Davison W, 2001. Effect of solution composition, flow and deployment time on the measurement of trace metals by the diffusive gradients in thin films technique. Analytica Chimica Acta. 448: 93-103.
  8. Havlin JL, JD Beaton, SL Tisdale, and WL Nelson. 2005. Soil Fertility and Nutrient Management: An Introduction to Nutrient Management. 7th Edition. Pearson/Prentice Hall. Upper Saddle River, NJ.
  9. Harper MP, Davison W, Zhang H and  Tych W, 1998. Kinetics of metal exchange between solids and solutions in sediments and soils interpreted from DGT measured fluxes. Geochim.Cosmochim. Acta. 62: 2757-2770.
  10. Hooda PS, Zhang H, Davison W and Edwards A C, 1999. Measuring bioavailable trace Metals by Diffusive Gradients in Thin Films (DGT): Soil Moisture Effects on its Performance in Soils. European Journal of Soil Science. 50: 285-294.
  11. Lehto N.; Davison W.; Zhang H.; Tych W, 2006. Theoretical comparison of how soil processes affect uptake of metals by DGT and plants. Journal of Environmental Quality. 35 (5): 1903-1913. ISSN 0047-2425.
  12. Marschner H, 1995. Mineral Nutrition of Higher Plants. London, UK, Academic Press Limited.
  13. Mason S, Hamon R, Nolan A, Zhang H and Davison W, 2005. Performance of a Mixed Binding Layer for Measuring Anions and Cations in a Single Assay Using the Diffusive Gradients in Thin Films Technique. Anal. Chem. 77, 6339-6346.
  14. McLaughlin M J, Hamon R E, McLaren R G, Speir TW and Rogers SL, 2000. Review: A bioavailability-based rationale for controlling metal and metalloid contamination of agricultural land in Australia and New Zealand. Australian Journal of Soil Research. 38: 1037-1086.
  15. Menzies NW, Kusumo B and Moody PW, 2004. Assessment of P availability in heavily fertilized soils using the diffusive gradient in thin films (DGT) technique. Plant and Soil. 269, 1–9.
  16. Meylan S, Odzak N, Behra R and Sigg L, 2004. Speciation of copper and zinc in natural freshwater. Anal. Chim. Acta. 510, 91.
  17. Munkhsgaard NC and Parry DL, 2003. Monitoring of labile metals in turbid coastal seawater using diffusive gradients in thin-films. J. Environ. Monit. 5: 145.
  18. Nolan A, Zhang H. and McLaughlin M, 2005. Assessment of metal availability to wheat in contaminated soils using chemical speciation, DGT, extraction and isotopic dilution techniques. Journal of Environmental Quality. 34: 497-506.
  19. Peters A J, Zhang H and Davison W, 2003. Performance of the diffusive gradients in thin films technique for measurement of trace metals in low ionic strength freshwaters. Analytica Chimica Acta. 478: 237-244.
  20. Scally S, Davison W and Zhang H, 2003. In Situ Measurements of Dissociation Kinetics and Labilities of Metal Complexes in Solution Using DGT Environ. Sci. Technol. 37, 1379.
  21. Sochaczewski L, Tych W, Davison W and Zhang H, 2006. 2D DGT induced fluxes in sediments and soils (2D DIFS). Environment Modelling Software. 22: 14-23.
  22. Warnken K,  Zhang H, and Davison W, 2005. Trace metal measurements in low ionic strength synthetic solutions by diffusive gradients in thin films. Analytical Chemistry. 77: 5440-5446.
  23. Williams C H and Raupach M, 1983. Plant nutrients in Australian soils. In  Soils: An Australian Viewpoint. Division of Soils, CSIRO. London, Academic Press. 777-793.
  24. Zhang H and Davison W, 1999. Diffusional characteristics of hydro gels used in DGT and DET techniques. Anal. Chim. Acta. 398, 329.
  25. Zhang H and Davison W, 1995. Performance characteristics of diffusion gradients in thin films for the in situ measurement of trace metals in aqueous solution. Anal Chem. 67: 3391-400.
  26. Zhang H, Davison W, Gadi R and Kobayashi T. 1998. In situ measurement of dissolved phosphorus in natural waters using DGT’. Analytica Chimica Acta, vol. 370: 29 – 38.
  27. Zhang H, Zhao FJ, Sun B, Davison W and McGrath SP, 2001. A new method to measure effective soil solution concentration predicts copper availability to plants. Environ. Sci. & Technol. 35: 2602-2607.
Land Management Journal
Volume 2, Issue 2
March 2015
Pages 137-150

Files

Share

How to cite

Statistics