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Potassium Fertility Effects Yield Components and Seed Potassium Concentration of Determinate and Indeterminate Soybean
Author(s) -
Parvej Md. Rasel,
Slaton Nathan A.,
Purcell Larry C.,
Roberts Trenton L.
Publication year - 2015
Publication title -
agronomy journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.752
H-Index - 131
eISSN - 1435-0645
pISSN - 0002-1962
DOI - 10.2134/agronj14.0464
Subject(s) - indeterminate , indeterminate growth , cultivar , yield (engineering) , point of delivery , glycine soja , agronomy , biology , glycine , ideotype , mathematics , amino acid , biochemistry , pure mathematics , metallurgy , materials science
Indeterminate maturity group (MG) IV soybean [ Glycine max (L.) Merr.] cultivars may be more susceptible to yield loss from K deficiency due to the shorter growing season and earlier onset of reproductive growth than MG V determinate soybean cultivars. Our objective was to identify whether indeterminate MG IV or determinate MG V soybean are affected differently by K deficiency. Seed yield and selected yield components were evaluated from a determinate (MG 5.3) and indeterminate (MG 4.7) soybean cultivar grown under three K fertility levels (low, medium, and high). The trial was conducted in long‐term plots that receive 0, 75, or 150 kg K ha −1 yr −1 . Yield and yield components of both the determinate and indeterminate cultivars responded similarly to K deficiency. Seed yield for soybean grown with low K averaged 3.4 Mg ha −1 and was 13 to 15% lower than the yields of soybean grown with medium and high K fertility. The yield loss associated with K deficiency was from fewer pods (16–25%) and seeds (22–30%) plant −1 , higher seed abortion (5–7%), and lower individual seed weight (8–10%) than soybean with medium or high K fertility. Seed K concentration increased with each increase in K fertility level averaging 15.8, 18.7, and 19.8 g K kg −1 for soybean grown under low, medium, and high K levels, respectively. Regardless of growth habit, the yield loss caused by K deficiency was attributed to the same primary mechanisms of reduced pod number and increased seed abortion.