2018
Phosphorus Fertilizer Management Decisions for Soybean Based on Time of Planting
Contributor/Checkoff:
Category:
Sustainable Production
Keywords:
GeneticsGenomicsSeed quality
Parent Project:
This is the first year of this project.
Lead Principal Investigator:
Jasper M. Teboh, North Dakota State University, Carrington Research Extension Center
Co-Principal Investigators:
Project Code:
QSSB
Contributing Organization (Checkoff):
Institution Funded:
Brief Project Summary:

Completed work
This trial was conducted at Minot, Carrington, Oakes, and Wishek, ND, to assess the effect of phosphorus fertilization on soybeans planted early, during normal planting period, or late (Table 1). The trial was successfully established, data collected, and harvested at all five environments, even though yields were impacted at Minot due to droughts in spring and summer of 2017. The P treatment rates assessed were, 0, 20, and 40 lbs P/ac applied as triple super phosphate, and incorporated. At Minot, where it was no-till, P was applied as DAP (18-46-0) at 0, 5, 10, 15 lbs/ac.


Trial Locations, growing conditions, and dates...

Unique Keywords:
#soil fertility
Information And Results
Project Deliverables

Research results from this study are expected to be shared with producers in the form of:
1. Presentations at research extension meetings involving county extension agents
2. Mid-year and final (technical) reports to the North Dakota Soybean Council (Mid-year completed)
3. Research Center Annual Reports that producers have access to, at various State Research Extension Centers
4. Present research results through online media, such as the Carrington REC Extension Center Point blog, such as the December 5, Center Points article at https://www.ag.ndsu.edu/CarringtonREC/center-points

Final Project Results

Updated July 9, 2018:

View uploaded report Word file

Title: Phosphorus fertilizer management decisions for soybean based on time of planting
Principal investigator: Dr. Jasper M Teboh, NDSU Carrington Research Extension Center
Co-Investigators: Eric Eriksmoen, NDSU North Central Research Extension Center; Szilvia Yuja, Kelly Cooper, Heidi Eslinger, Blaine G Schatz, NDSU Carrington Research Extension Center, Dr. Dave Franzen, Department of Soil Science, NDSU.
How do soybean yields differ in response to phosphorus (P) applied when planted early or later? This study assesses soybean yields as impacted by P fertilizer application when planting is early, normal time, or later, and provides an assessment of the resulting yields on net return.
Planting dates used are shown on table 1. P rates were 0, 20, 40 lbs P/ac as triple super phosphate surface applied and incorporated. At Minot, soybean was no-till and P banded with 11-52-0 at 5, 10, and 20 lbs of P2O5 /A. Both Carrington sites tested medium for P, while other sites were high.
Table 1. Locations and planting dates

Planting
time Locations
-------Carrington ------- Minot Oakes Wishek
Dryland Irrigated Dryland Dryland Dryland
Early 11-May 11-May 10-May 10-May 9-May
Normal 24-May 24-May 19-May 24-May
Late 8-Jun 8-Jun 30-May

Results
Across all sites, the effect of P on soybean yield did not depend on planting date (Table 1). At Carrington, under dryland, early planting and normal planting dates produced significantly greater yields than late planting (Figure 1).
• At the Carrington irrigated site, P rate and planting date impacted yields, significantly. Planting on or before May 24 improved yields by almost 12 bushels on average. Yields from early and normal planting dates were not different. P treatments produced results which could not be explained (e.g., greater yields at 0 and 40 lbs treatments than at 20 lbs) but would be verified in ongoing studies.
• At Oakes, yields were significantly increased by P. Yields were not different between 20 and 40 lbs, but improved by 6.5 bushels compared to the check (0 lbs P). Planting on May 10 (early/normal) had a marginally significant yield increase (about 4.5 bushels) compared to planting two weeks later.
• At Minot, prolonged droughts led to low yields, which were half the normal. Yields were not different among treatments.
• At Wishek, yields were also not different between P rates.
• Economically, only the farmer at Oakes would have made some profit. At $8.5/bu for soybeans, $0.707/lbs P fertilizer, and $6.39/ac application cost, the Oakes farmer who applied 20 lbs compared to 0 lbs, would have gained $13/ac, and at 40 lbs, $5/ac when averaged across the two planting dates. Net loss of $25 was estimated at 40 lbs P, at late planting.
• From these results farmers would be better off planting near the second week of May, to boost yield potentials and net return.

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.