A Comparison of Three Methods for Reducing Iron‐Deficiency Chlorosis in Soybean

Abstract

Iron‐deficiency chlorosis is common when soybean [Glycine max (L.) Merr.] is grown on calcareous soils. The objective of this study was to compare the relative effectiveness of cultivar selection, foliar sprays, and FeEDDHA seed treatment for reducing chlorosis and increasing the yield of soybean planted in 15‐cm rows. Three cultivars (‘Glacier’, ‘Council’, and ‘Traill’) were grown in a factorial combination with two levels of foliar spray (control vs. two FeEDTA sprays) and two levels of seed treatment (control vs. FeEDDHA seed treatment). The cultivars gave an expected chlorosis response, with Glacier being the most susceptible, and Traill being the most resistant. Foliar sprays significantly (P ≤ 0.05) reduced chlorosis at two sites. Seed treatment with FeEDDHA did not reduce chlorosis although this treatment was effective in prior studies with soybean planted in 76‐cm rows. Iron treatments did not reduce the chlorosis scores of Glacier to the level of Council or Traill without Fe treatments. Seed yields were significantly different for cultivars at all sites. Averaged across sites and Fe treatments, the yields were 1361, 1913, and 2203 kg ha−1, for Glacier, Council, and Traill, respectively. Foliar sprays tended to increase the yield of Glacier at two sites and significantly increased the yield of all three cultivars at another site. The yield responses to foliar sprays, when obtained, were about 300 kg ha−1. FeEDDHA seed treatment did not increase seed yield. Cultivar selection remains the most practical control measure for Fe‐deficiency chlorosis of soybean grown in narrow rows.