Postseason Diagnosis of Potassium Deficiency in Soybean Using Seed Potassium Concentration. Issue 5 (30th August 2016)

• Record Type: Journal Article
• Authors: Parvej, Md. Rasel; Slaton, Nathan A.; Fryer, Matthew S.; Roberts, Trenton L.; Purcell, Larry C.
• Is Part Of: Soil Science Society of America Journal. Volume 80:Issue 5(2016)
• Page Start: 1231
• Page End: 1243
• Publication Date: 2016-08-30
• Subjects: Soils -- United States -- Periodicals; Soil science -- Periodicals; Periodicals; 631.4973
• DOI: 10.2136/sssaj2016.02.0030
• Languages: English
• ISSNs: 0361-5995

Abstract

Abstract : Core Ideas: Seed‐K concentrations accounted for 60% of the variation in relative yield of unfertilized soybean for 100 site‐years in North America. The proposed deficient seed‐K concentration (<16.5 g kg −1 ) identified fields that responded positively to fertilizer K 77% of the time. Seed‐K concentration difference with and without fertilizer K decreased with the increase of soil K. Seed‐K concentrations can help diagnose reasons for low yields and correct K deficiency for subsequent crops. Soybean [ Glycine max (L.) Merr.] seed nutrient concentrations may be useful for postseason diagnosis of nutrient deficiencies to identify reasons for lower‐than‐expected yields. Our objective was to determine the relationships between seed‐K and soil‐K concentrations and relative soybean yield and to develop potential seed‐K concentration thresholds for diagnosis of K deficiency as a yield‐limiting factor. Soil‐test K and seed‐K concentrations and yield data were collected from published and unpublished K fertilization research conducted in Arkansas (33 site‐years), Indiana (1 site‐year), Iowa (34 site‐years), Missouri (1 site‐year), Tennessee (6 site‐years), Virginia (1 site‐year), and Canada (24 site‐years). Seed‐K concentrations accounted for 66% of the variation in relative yield of soybean receiving no fertilizer K for Arkansas, 48% for Iowa, 78% for Canada, and 60% for North America from a database that included 100 site‐years. The critical seed‐K concentration ranges were 15.6 to 17.0 g K kg −1 for Arkansas, 17.4 to 20.0 g K kg −1 for Iowa, 14.6 to 16.2 g K kg −1 for Canada, and 16.5 to 17.7 g K kg −1 for North America. Seed‐K concentrations below the lower threshold for North America accurately predicted positive yield responses to fertilizer K at 77% of the sites classified as deficient. The difference between seed‐K concentration of soybean grown with and without fertilizer K decreased linearly as soil‐K concentration increased and plateaued when soil‐K concentration was ≥87, 139, 73, and 104 mg K kg −1 for Arkansas, Iowa, Canada, and North America, respectively. Results suggest that seed‐K concentrations can be used to aid in the diagnosis of K deficiency at maturity.