Potassium Fertility Effects Yield Components and Seed Potassium Concentration of Determinate and Indeterminate Soybean. (1st May 2015)

• Record Type: Journal Article
• Authors: Parvej, Md. Rasel; Slaton, Nathan A.; Purcell, Larry C.; Roberts, Trenton L.
• Is Part Of: Agronomy Journal. Volume 107:Number 3(2015)
• Page Start: 943
• Page End: 950
• Publication Date: 2015-05-01
• Subjects: Agronomy -- Periodicals; 630
• DOI: 10.2134/agronj14.0464
• Languages: English
• ISSNs: 0002-1962

Abstract

Abstract : 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.