Micronutrient Content of Irrigated Soybean Grown in the Midsouth.

Micronutrients are essential to soybean (Glycine max L. Merr.) growth but required in minute quantities.  Concentrations and tissue contents of Fe, B, Zn, Mn and Cu were determined for two MG IV and one MG V irrigated cultivars grown in twin-rows in the Mississippi Delta on a Dundee silty clay (fine-silty, mixed, active, thermic Typic Endoaqualfs) and a Bosket fine sandy loam site (fine-loamy, mixed, active, thermic Mollic Hapludalfs), near Stoneville, MS  in 2011 and 2012.  Plants were sampled at growth stages V3, R2, R4, R6 and R8, their tissues separated, dried, weighed and ground for later nutrient concentration assays.  Total nutrient contents were calculated from these data.  No cultivar, site or year differences in concentrations or contents of the nutrients were observed.  Iron had the greatest concentration and plant content of all elements at all growth stages, followed by B, Zn, Mn and Cu.  Due to the elements being immobile, maximum concentrations and contents in leaves were acquired at R4 and declined as leaves senesced.  In stems both concentrations and contents remained constant, or increased during this time, while seed containing pods rapidly increased until (R8).  These data show a 3328 kg ha^-1 seed yield will remove about 325.0 g Fe ha^-1, 153.9 g B ha^-1, 175.6 g ha^-1, 100.0 g Mn ha^-1 and 52.5 g Cu ha^-1.