Feed the Bean JAMIE LONG C C A
Feed the Bean JAMIE LONG, C. C. A. JOSH GUNTHER, C. C. A.
Six secrets to soybean success Weather Fertility Genetics/Variety Foliar protection Seed treatment Row spacing Dr. Fred Below, University of Illinois
Liebig’s law of the minimum Weather Fertility Genetics/Variety Foliar protection Seed treatment Row spacing Dr. Fred Below, University of Illinois
Poll question: Who already fertilizes their soybeans? ◦Following corn? ◦Following soybean?
Historical fertilizer practices Fertilize prior to corn, let soybeans scavenge the nutrients N, P, K, lime according to soil tests and removal rates for both corn and soybean How could this limit soybean yields?
Why fertilize soybeans? To achieve higher yielding soybeans
So now you’re going to fertilize your soybeans…. What do you apply? When do you apply?
First things first… What are your current nutrient levels?
Soil testing Necessary for knowing soil nutrient levels Above optimum levels of nutrients – don’t need to fertilize
Tissue testing Help track in-season deficiencies Top trifoliate – reproductive stages After deficiency is determined, yield is already lost
Correct p. H
Macronutrients Nitrogen (N) Potassium (K) Phosphorous (P)
Nitrogen uptake by soybeans How do soybeans meet their nitrogen requirement? ◦ Fix N through symbiotic relationship with Bradyrhizobium japonicum ◦ Nodules ◦ Mineralized nitrogen from soil ◦ From previous corn crop ◦ Organic matter
University of Delaware
Is a N application needed? Very high yield environments increase the likelihood of seeing a positive yield response ◦ R 3 timing Early season N – can help in environmental conditions where nodulation is delayed Before applying N – make sure it is the only limiting nutrient
Potassium (K) Arguably more important in soybean production than Phosphorus K deficiency proven to have more of a yield restriction than P deficiency Must maintain K levels above the Critical Level
Michigan State University Extension
Potassium Critical level Multiply CEC X 2. 5 and add 75 [(CECX 2. 5)+75] Ex If you have a soils where the CEC is 12 meq per 100 g the critical level for K is 105 ppm [(12 X 2. 5)+75]=105 ppm K Maintenance Range for K is 30 ppm Ex maintenance range is 105 -135 ppm
Michigan State University Extension
Buildup Range: <Critical Level Higher recommendation than removal rate Maintenance Range: Between Critical and Maintenance Limit Recommend removal rate Drawdown Range: >Maintenance Limit Recommend lower than removal rate
Removal Rate of K Soybeans remove 1. 4 lbs of K 20/bu Ex 80 bu/ac field 80 x 1. 4= 112 lbs K 2 O If we need to replace 112 lbs K 2 O that would be 187 lbs Muriate of potash (0 -0 -60)/ac 112/. 6=187
K recommendation will change slightly with soil’s CEC University of Illinois & Robert Mullen Ph. D.
Phosphorous (P) More straight forward than K Critical Level – 15 ppm Maintenance Range – 15 – 30 ppm
Michigan State University Extension
Removal Rate P Soybeans remove 0. 8 lbs P 2 O 5/bu Ex 80 bu/ac field 80 x 0. 8= 64 lbs P 2 O 5 If we need to replace 64 lbs P 2 O 5 that would be 123 lbs of MAP or 139 lbs of DAP 64/. 52=123 lbs MAP 64/. 46=139 lbs DAP
P recommendation will change with different yield levels. University of Illinois & Robert Mullen Ph. D.
Application Methods -Broadcast -Deep Banding -2 X 2 Starter -Foliar -Broadcast performs equal to or better when above Critical Level ◦ Best if lightly incorporated -Band applications are most effective if below Critical Level
Secondary nutrients Calcium Magnesium Sulfur
Sulfur for soybeans Lack of atmospheric deposition – declining sulfur Sulfur may be limiting especially in coarsetextured soils that are low in O. M. If lacking sulfur – apply prior to planting Dr. Shaun Casteel, Purdue – consistent increase with S additions
Micronutrients Boron Chlorine Cobalt Copper Iron Manganese Molybdenum Nickel Zinc
What are micronutrients? Essential plant nutrients used in very small amounts Unlike macronutrients – removal rates are not calculated May become limiting with higher yielding soybeans
Removal rates What about for 100 bu soybeans?
Micronutrient research No consistent yield response and sometimes negative response (Boron) Consider soil and tissue test results Soil and environmental conditions
Prediction from soil test
Prediction from tissue test
When are micronutrients recommended?
Foliar applications – University Research
Summary Conduct regular soil and tissue sampling to identify limiting factors ◦ p. H, K, P, possibly N and S Consider return on investment of fertilizer applications Conduct replicated trials on your farm
Six secrets to soybean success Weather Fertility Genetics/Variety Foliar protection Seed treatment Row spacing Dr. Fred Below, University of Illinois
Questions?
- Slides: 42