2019
Irrigated Full Season Soybean Response to Nitrogen, Sulfur, and Complete Fertility Programs
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Contributor/Checkoff:
Delaware Soybean Board
Category:
Sustainable Production
Keywords:
GeneticsGenomicsSeed quality
Parent Project:
Irrigated Full Season Soybean Response to Nitrogen, Sulfur, and Complete Fertility Programs
Lead Principal Investigator:
Cory Whaley, University of Delaware
Co-Principal Investigators:
Jarrod Miller, University of Delaware
Phillip Sylvester, University of Delaware
+1 More
Project Code:
Contributing Organization (Checkoff):
Delaware Soybean Board
$9,461
Institution Funded:
University of Delaware
$9,461
Brief Project Summary:

Soybean yields have been gradually increasing due to genetic and management improvements. In high-yield scenarios under irrigation, they may not have the ability to fix or obtain enough nitrogen to maximize yields. Some of the sandy and low organic matter soils in Delaware may not be able to supply sufficient sulfur in a high-yield scenario. This project gathered local data on locally on applying supplemental N and S to irrigated full-season soybeans via fertigation, as farmers have reported positive yield responses to this practice at flowering, beginning pod or beginning seed fill growth stages. It also evaluates the effect of high fertility levels on yield and tissue analysis.

Key Benefactors:
farmers, agronomists, Extension agents

Information And Results
Project Deliverables

Final Project Results

Updated November 30, 2020:

View uploaded report PDF file

In research conducted at the University of Delaware Warrington Irrigation Research Farm in 2015, 2016, 2017, 2018, and 2019 a significant yield increase with N + S applications compared to the control have been observed in 4 out of 5 years. In 2015 and 2016, there was an 8 bu/A increase in yield when N + S (30 lbs/A + 15 lbs/A) was applied at the R1 growth stage compared to the no fertigation treatment. In 2017, the R1 application yielded similarly to the no fertigation treatment, however there was a 7 bu/A increase in yield over the no fertigation treatment when N + S was applied at R1 and again at R3 (60 lbs/A N + 30 lbs/A S total). In 2018, there was not a significant yield response with any rate or timing of N + S. In 2019, there was a 4 bu/A yield increase over the no fertigation treatment when N + S was applied at V3 + R1 (60 lbs/A N + 30 lbs/A S total), however this treatment was statistically similar to all other fertigation treatments except the treatments at V3 (30 lbs/A N) and at R1 (30 lbs/A N + 15 lbs/A S).

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.