Evaluating the Interaction Between Chelated Fe Source and Placement on Phosphorus Availability in Soybean.

Increasing yield with the application of chelated metals has been studied extensively since the 1920’s.  In agriculture, chelating agents are used to supplement micronutrients, such as iron (Fe).  However, little research has been conducted on a field scale to observe chelating agent effects on phosphorus (P).  The objectives of this study were to evaluate three commercially available chelated Fe sources on early soybean growth and nitrogen (N), P, and potassium (K) uptake.  The study was conducted at two locations where the experimental design was a randomized complete block with four replications in a factorial arrangement. The two factors included chelated Fe source by fertilizer placement.  The chelating agents tested were EDTA-Fe, HEDTA-Fe, and a glucoheptanate product with two fertilizer placements, in furrow with seed contact and surface band.  Results show that all in furrow chelate and fertilizer application had a negative effect on population germination compared to surface banding.  The glucoheptanate product and HEDTA-Fe were found to increase soybean P uptake at the V-4 growth stage.  In furrow application of HEDTA-Fe and the glucoheptanate product was found to increase nitrogen uptake and chlorophyll SPAD readings at the V-4 growth stage.  Effects of chelating agents on yield and grain nutrient concentrations are to be determined.