2019
A decision support tool for phosphorus application in soybean fields that have a “high” soil test phosphorus rating
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Contributor/Checkoff:
Alabama Soybean Producers
Category:
Sustainable Production
Keywords:
GeneticsGenomicsSeed quality
Parent Project:
This is the first year of this project.
Lead Principal Investigator:
Rishi Prasad, Auburn University
Co-Principal Investigators:
Dennis Delaney, Auburn University
Audrey Gamble, Auburn University
+1 More
Project Code:
Contributing Organization (Checkoff):
Alabama Soybean Producers
$18,049
Institution Funded:
Auburn University
$18,049
Brief Project Summary:

Soybeans need phosphorus for photosynthesis throughout the season and especially during pod formation. Too much P can pose an environmental risk, prompting application guidelines based on soil tests. Many Alabama soils are high in aluminum and iron oxides that bind P under acidic conditions, making it unavailable. Current soil tests measure plant-available P, but they don’t reveal if those soils are capable of storing additional P. To better assess how soils interact with P, the research quantifies P storage capacity of Alabama soils to then develop a decision support tool to help determine when P can be applied or stopped to those P-fixing soils.

Key Benefactors:
farmers, agronomists, Extension agents

Information And Results
Project Deliverables

Soils samples (0-6, 6-12, 12-24 inch depth) will be collected from soybean fields across the state of Alabama that have a history of litter or P based fertilizer application. These soil samples will be brought to the laboratory, dried and extracted using water, oxalate, Mehlich-1 and Mehlich-3 methods. The extract will be analyzed for extractable P, Fe and Al. Soil phosphorus storage capacity (SPSC) will be determined based on the methods developed by Nair and Harris (2004). The relationship between different extractants and SPSC will be evaluated for different Alabama soils. The best extractant for SPSC calculation will be determined and growers will be informed of the phosphorus storage capacity of their soil.

Final Project Results

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.