Mobilization of Iron from Calcareous Vertisol to Minimize Iron Deficiency Chlorosis of Soybean [Glycine max (L.) Merr.]

Abstract

Iron deficiency chlorosis (IDC) is an abiotic nutritional stress prevalent on calcareous and high pH soils and its management is very essential for realising better yield of crop plants. In the present study, a pot culture experiment was conducted with the objective to minimise IDC of soybean plant using iron-efficient and responsive (FeER) soybean genotype viz. NRC-45 as test crop. An Fe inefficient and responsive (FeIR) genotype viz. IC-18374 was included in the study to compare the relative efficiency of contrasting genotype in mobilizing soil Fe. Twelve treatments were used in the experiment, which includes soil amendments such as sulphitation press mud (SPM) and iron pyrite applied either alone or in combination with micro- organisms like arbuscular mycorrhizal (AM) fungi or Piriformospora indica. Application of partially decomposed SPM in combination with Aspergillus niger to FeER genotype significantly improved the DTPA extractable Fe content of the soil from 2.20 to 5.75 mg kg-1. Among the treatments, T6 comprised of FeER in combination with the application of 5 g SPM kg-1, 12.5 mg FeSO4 kg-1 and AM Fungi recorded the highest Fe concent-ration (59.7 mg g-1) in the stover at 60 days after sowing (DAS). Further, significantly higher chlorophyll content was observed in T6 (2.55 mg g-1) and T2 (2.53 mg g-1) at 60 DAS as compared to the T1 (Control). Treatment consisting of 12.5 mg FeSO4 kg-1 soil, partially decomposed SPM along with dual inoculation of AMF and Aspergillus niger to an FeER genotype of soybean was found to control Fe deficiency chlorosis.