Availability of Zinc to Different Organic Ligands Under Reduced Conditions in Constrasting Rice Soils

Rice plants sometimes exude organic acids or phytosiderophores into the soil through the roots. These compounds chelate metal cations, such as Zn2+, increasing the availability for nutrient uptake by the plant. And because the chemistry of flooded soils causes many changes in the type and concentration of the cations that are present to react with these chelating compounds, it is expected that the effectiveness of root exudates to mobilize Zn will vary depending on soil conditions (Lombnaes et al 2008). It is therefore important to understand how these ligands interact with Zn in various soil types. The objective of the study was to extract Zn from farmers' fields from selected areas in the Philippines with contrasting properties to compare the extraction capacity of three ligands representing different types of root exudates.