2019
Assessment of Soil Potassium Bioavailability and Improving Diagnostics Tools for K Management on Soybean in Kansas
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Contributor/Checkoff:
Kansas Soybean Commission
Category:
Sustainable Production
Keywords:
GeneticsGenomicsSeed quality
Parent Project:
This is the first year of this project.
Lead Principal Investigator:
Dorivar Ruiz-Diaz, Kansas State University
Co-Principal Investigators:
Project Code:
1951
Contributing Organization (Checkoff):
Kansas Soybean Commission
$43,329
Leveraged Funding (Non-Checkoff):
Nutrien $5,000
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Institution Funded:
Kansas State University
$43,329
Brief Project Summary:

The goal of this project is to improve potassium management for soybean production in Kansas, increasing yields with improved diagnostic tools and fertilization strategies based on soil types in the main soybean producing regions in Kansas. Specific objectives include: determining the impact of K deficiencies on soybean yields for different soil types; evaluating current soil test interpretations for K fertilization in soybean, including new soil test methods and the effect of soil clay types on critical levels; assessing plant K levels during the growing season and determining yield limitations related to the high rate of K uptake.

Key Benefactors:
farmers, agronomists, applicators, ag retailers

Information And Results
Final Project Results

Update:
The 2019 field locations were harvested to measure yield response, plant samples were collected, and fall-spring soil sampling completed. Field experiments were also conducted at two locations during 2019 to evaluate the alternative soil test methods (ion exchange resin, CER). Treatments included a control (check) with no K application and one with an application of 150 lbs K2O acre-1 (high K rate).

Preliminary results showed that plant K uptake measured at reproductive stages (R2, R4, and R6) was increased by K fertilization. However, differences were not statistically significant (p < 0.05) at locations with high soil test K. In contrast, locations with low soil test K showed significantly higher plant K uptake measured at R2 (p < 0.05), R4 (p < 0.10), and R6 (p < 0.05) stages when 150 lbs K2O acre-1 was applied.

At the R6 stage, fertilized plots had 50% more K uptake and 40% more K adsorption (cumulative) by CER compared to the control. This observation suggests the potential use of CER as an indicator of K supply to soybean in field conditions, but further research is needed and ongoing in 2020. In both locations, CER was able to adsorb more K (measured as cumulative adsorption) at a high K rate. The amount of K that was adsorbed by the CER was influenced by soil moisture content. Field evaluation of crop response and soil test methods will continue during the 2020 soybean growing season.

View uploaded report PDF file

The United Soybean Research Retention policy will display final reports with the project once completed but working files will be purged after three years. And financial information after seven years. All pertinent information is in the final report or if you want more information, please contact the project lead at your state soybean organization or principal investigator listed on the project.