Project

Towards a mechanistic basis for the DTPA/EDTA-extraction for establishing the micronutrient availability in soils

Poor availability of micronutrients like Fe, Zn, Cu and Mn can limit primary productivity and dramatically reduce crop yields. Micronutrient deficiency in crops is particularly (but not exclusively) observed on alkaline and calcareous soil (pH > 7), which cover approximately one third of the earth's land surface.

Background

For farmers it is of great importance to be aware of the micronutrient status of their land in order to apply sufficient fertiliser. The common method for evaluating the micronutrient status of agricultural soils, which has been used for decades, is by means of an EDTA or DTPA extraction. EDTA and DTPA are chelating agents that can strongly bind metals and bring them into soil solution by forming soluble complexes. Although threshold values for the various micronutrients are available, below which deficiency in crops is to be expected, the relation between the EDTA/DTPA-extracted concentration and the actual available micronutrient content in the soil is still a mystery.

This MSc thesis project aims to finally provide a mechanistic basis for this extraction method. By comparing the results from kinetic batch experiments with EDTA /DTPA with multi-surface modelling predictions for a range of soils, it will be established if equilibrium modelling can predict the micronutrient concentrations mobilized in the standard EDTA/DTPA extraction protocol.

Used skills

  • Literature review;
  • Proposal writing;
  • Laboratory (soil extraction, kinetic batch experiments);
  • Multi-surface modelling;
  • Data processing;
  • Thesis writing.

Requirements

  • Some laboratory experience required;
  • Required courses for the MSc thesis Soil Chemistry and Chemical Soil Quality (SOC-81336):
    • Preferably including Application in Soil and Water Chemistry (SOC34806).

Supervisor