1. PURSUIT OF SUSTAINABLE HIGH-YIELDING SOYBEANS
WITH A FOCUS ON M.O.M.
Howard Brown
Mgr. Agronomic Information and Environmental Stewardship
ILLINI FS

2. NUTRIENT PLANNING? 17 Essential Nutrients
Liebig’s Law of the Minimum (Nutrients)
Extrapolated Vision of the Law of the Minimum

3. LAW OF THE MINIMUM Lost Yield Potential S Mn Zn B N N

4. STAVES IN THE BARREL Genetics Plant Stand Plant Health Plant Nutrition
Row Spacing

5. SOYBEAN YIELD Yield is dependent on three components
total number of pods/ plant
number of beans/pod
weight of bean (seed size)
Yield increases result from increases in total pods/plant
The upper limits on beans/pod are genetically limited
Pods per plant image:
Beans per pod image:

6. SOYBEAN NUTRIENT REQUIREMENTS
Fertilizing soybeans not common
Visual deficiency symptoms rare (exceptions)
Use soil test to determine fertilizer application
Plant analysis to help diagnose deficiency
Nutrient considerations

7. NUTRIENTS ESSENTIAL TO PLANT GROWTH
Zinc
Manganese
Iron
Copper
Boron
Chlorine √
Molybdenum √
Nickel √
Carbon
Hydrogen
Oxygen
Free from
Atmosphere
Nitrogen
Phosphorus
Potassium
Common
Fertilizer
Programs
Calcium
Magnesium
Sulfur
Ca & Mg
Adequate
Sulfur?

8. COLLECTIVE USE OF MACRONUTRIENTS
Pounds Nutrient / Acre Used
NUTRIENT
30 Bushels
50 Bushels
70 Bushels
Nitrogen
165
275
385
Phosphorus
16 (37)
27 (62)
37 (85)
Potassium
61 (73)
101 (121)
141 (169)
Calcium 51 85
119
Magnesium 14 22 31
Sulfur 23 32
( ) Lbs/A Oxide form on nutrient
P x = P2O5
K x = K2O

9. NITROGEN and GROWTH Rhizobia fix approx. 50% of N needed
Use inoculum where soybeans not freq. crop
N at planting decrease nodulation/dependence?
No consistent yield results in research
Beneficial specific years/specific locations

10. NITROGEN N is related to vegetative growth
N-fixation begins about 2 weeks following emergence
Plant relies on residual N until then
N-Fixation decreases rapidly during seed development (R5)
Remobilization of N related to maturity color
Cloudy days in August impacts grain fill (also N fixation)

11. ON-FARM DISCOVERY PROJECT: Nitrogen
Pre-Plant
30 lbs N
Maintenance P2O5 for 90 Bu/A as DAP
Post-Emerge (R3-R4)
30 to 50 lbs N at pod set
Urea with Agrotain

12. NUTRIENT MANAGEMENT Follow Agronomy Handbook Guidelines for P and K
Optimum P1 and K Test Levels – Yield Maintenance
.85 lbs P2O5/Bu
1.3 lbs K2O/Bu
Yield
70 Bu.
80 Bu.
90 Bu.
100 Bu.
Lbs/A DAP
129
148
166
185
Lbs/A Potash
152
174
195
217

13. SOIL LOADED WITH CALCIUM/MAGNESIUM

15. Twenty S Rate Sites in 2007, N. E
Twenty S Rate Sites in 2007, N.E. Iowa Soils: 14 loam and silt loam, 6 loamy sand and sandy loam
15 bu/acre
25 bu/acre
Source: Dr. John Sawyer, Iowa State University

16. No Sulfur
20 lbs. Sulfur

17. ON-FARM DISCOVERY SULFUR STUDY

18. EVALUATION Use sulfate-S as the source Gypsum (mined or Sul-4R-Plus)
AMS
MicroEssentials (MES)
ATS
15 – 20 lbs S (as sulfate-S)

19. OTHER NUTRIENTS Chlorine, Molybdenum, or Nickel
Consider: Iron, Manganese, Zinc, Copper, Boron
If high pH is an issue – Foliar delivery suggested.

20. CONSIDERATIONS Soybeans are an annual plant
Soybeans abort up to 75% blooms/young pods
Stress during fill period most significant on yield

21. PLANT HEALTH Seed treatment to assure a good start
Inoculant if it fits into plan
Fungicide to protect leaf area
Insecticide to do the same

22. ON-FARM DISCOVERY Select field that represents most acres
Minimize factors identified
Compare treatments to traditional practices

23. NUTRIENT MANAGEMENT PLANNIING
Think Liebig’s Law of the Minimum
Focus on pods per plant
Reduce stress to minimize flower/young pod abortion
Optimize growing environment during fill period
Work to minimize stress along the way

24. NUTRIENT PLANNING Use what knowledge research has provided
Consider SCN, Inoculation, early growth
Don’t be quick to throw away traditional thinking
Consider stewardship when using additional inputs
Always test before plunging (Utilize the technology)
“If it seems too good to be true, it likely isn’t.”

25. NUTRIENT UTILIZATION STRATEGY
It’s about utilization
It’s about accountability
It’s about
Minimizing environmental impact
Optimizing yield
Maximizing nutrient utilization.

26. Good things happen when you focus on M.O.M.

27. “The only way of finding the limits of the possible is by going beyond them into the impossible.”