Iron Chelates Alleviate Iron Chlorosis in Soybean on High pH Soils

Abstract

High pH soils frequently lead to iron deficiency chlorosis (IDC) in soybean [Glycine max (L.) Merr.]. As a result, yields for soybean are often reduced. Studies in the north-central United States have shown improvements in grain yield after applying Fe chelates on calcareous soils, but this practice has not been evaluated in a southern climate. Two sites within the Blackbelt region of Alabama were evaluated for response to Fe-EDDHA, Fe-Citrate, and FeSO 4 for their effect on yield and chlorosis in 2010, 2011, and 2012. Treatments were applied in-furrow at planting, as a foliar spray at the V3 growth stage, or as a split-application. Remote sensing, relative chlorophyll meter readings, and visual chlorosis scores (VCS) were assessed as methods for identifying degree of Fe chlorosis. At the location where IDC was most pronounced, all treatments of Fe-EDDHA were effective at reducing VCS ratings when applied in-furrow at planting; however, chlorosis evaluation through remote sensing and relative chlorophyll readings was not able to detect improvements in chlorosis measured with VCS. Treatments of Fe-EDDHA at 4.5 kg product ha -1 increased yield whether applied as an in-furrow at planting treatment or as a split application at planting and at V3 growth stage as a foliar spray. Treatments of Fe-Citrate and FeSO 4 did not improve yield as applied in this study. Results suggest that Fe-EDDHA can be used in southern climates as a strategy to overcome IDC yield limitations.

Iron Availability and Management Considerations: A 4R Approach

“…Gamble et al. (2014) found a soybean yield increase of 2.98 bu/ac across a multiyear study at two high‐pH sites in Alabama. Foliar sprays containing iron salts or chelates are effective at correcting plant iron deficiencies during the growing season, but they may require repeated applications to prevent reoccurrence of deficiency.…”

“…Iron fertilizers protected with an organic chelate can be effectively applied to soils to correct plant deficiencies. Chelated fertilizers such as Fe‐EDDHA (Kaiser et al., 2014; Gamble et al., 2014) have been used with reasonable effectiveness, but their cost may be prohibitive for whole‐field applications. Gamble et al.…”

Complete Issue

“…Iron fertilizers protected with an organic chelate can be effectively applied to soils to correct plant deficiencies. Chelated fertilizers such as Fe-EDDHA (Kaiser et al, 2014;Gamble et al, 2014) have been used with reasonable effectiveness, but their cost may be prohibitive for whole-field applications. Gamble et al (2014) found a soybean yield increase Iron deficiency in maize.…”

How Raised Beds and Fe-Chelate Affect Soybean Iron Deficiency Chlorosis and Yield

“…Products combating IDC are often applied as in-furrow applications or foliar sprays as demonstrated by Gamble et al [12] in a soybean study in Alabama, USA. Visual chlorosis scores were lowered (less IDC) for in-furrow application and foliar spray, but in-furrow application resulted in the most IDC reduction although both methods provided similar yield [12].…”