Slide 1: Fertilizing Corn: Recommendations for 2008
Dr. Dave Franzen, Extension Soils Specialist, Fargo Contributor- Greg Endres, Carrington R & E Center
Slide 2: A 100 bu/acre corn crop contains the following nutrients: lb/acre N 160 70 P2O5 K2O 125 S 18 Zn 0.3
Slide 3: 2008 NDSU Nitrogen recommendations for corn
Slide 4: Our N recs were developed for lower yield potential than today, and do not consider crop or fertilizer prices.
Yield Goal
Most of the yield came from the linear portion of a curvilinear graph.
N rate
At N prices around 8-12 cents/ lb N, these recommendations were acceptable.
Slide 5: Economic optimum N rates in high, medium and low yielding years.
NET REVENUE, $/acre
200 150 100 50 0 -50
0
40
80
120
160
200 Schlegel et al., 1996, KS
N rate, lb/acre
Slide 6: Our data show that “yield goal/potential” is not a good predictor of optimal economic N rate.
Optimal N rates tend to be similar over a wide range of environmental conditions. Poor to normal growing years require similar N rates to above normal growing condition years.
Slide 7: What several states (Minnesota, Iowa, and Illinois) are doing now is calculating the “Return to N” based on their data base, cost of N and price of commodity.
Slide 8: MINNESOTA CORN RECOMMENDATIONS Corn/Corn Corn/Soybean
MRTN Range MRTN Range N price/ Corn value ----------------- lb/acre -------------------ratio
0.05 0.10 0.15 0.20
155 140 130 120
130-180 120-165 110-150 100-140
120 110 100 85
100-140 90-125 80-115 70-100
*Subtract soil test nitrate X 0.6
Slide 9: North Dakota has no “official” changes for our corn recs, but given the apparent efficiency of modern corn hybrids for N uptake, consider the following: • N = Yield Potential X 1.1 lb N/acre less credits. If you want a round number: 120-150 lb N/acre less credits. (don’t go lower than 100 lb N/acre or higher than 180 lb N/acre, less credits )
Slide 10: Take advantage of N credits from previous crops
Crop soybean dry bean field pea N Credit 40 lb/acre
Slide 11: N deficiency begins on lower leaves, starting at the leaf tip, and then following the midrib towards the stalk.
Slide 12: SIDEDRESS APPLICATION
Slide 14: POST foliar (broadcast) application of dry or liquid fertilizer on corn?
•No!
Slide 15: 2008 NDSU P and K recommendations for corn
Slide 16: P deficiency symptoms in corn
Slide 17: Banded placement helps P availability for grass crops.
Slide 19: Corn yield with in-furrow 10-34-0, Carrington, 2007.
*Conventional tillage *Soil : 124 lb N/acre prior to planting; 5 ppm (L) P2O5
Rate Gal/ac 0 2 4 6 8 10
Yield Bu/ac 101 121 125 150 156 153
P. Hendrickson
No difference in plant stand among fertilizer rates
Slide 20: Phosphate Inoculants
• Contain soil fungus which acidifies immediate environment • Crop response in soils with:
1. >7 pH 2. free carbonates (coated or ‘occluded’ P) 3. > med P Up to 10 lb/acre P2O5 can be released for use by crop
Slide 21: Phosphate Inoculants
• NDSU research:
– Corn: none – Soybean: 6 site-yr at Carrington (2002-06) = no yield response – Wheat- no P response (Goos 1994)
Slide 22: Corn Plant Potassium (K) Removal
Plant K content in crops
Crop Grain Stover Total K2O removal- grain* Lb K2O/a
-------- lb/bu K2O -------
Corn Wheat Soybean
0.3 0.3 1.4
1.2 1.6 1.0
1.5 1.9 2.4
39 15 56
* 130 bu/a corn, 50 bu/a wheat, 40 bu/a soybean
Slide 23: K deficiency symptom in corn
Slide 24: 140 135 130 124 125 125 118 120 115 110 105 0 7.5 15
137 133 132
Corn yield, bu/a
30 K2O rate
60
90
Influence of row (2 x 2) placed K on corn yield, Bushnell SD, 2000
Slide 25: Sulfur
• Deficiency symptoms
– stunted, spindly plants with light green color – upper leaves show light green color first – interveinal yellowing or leaf striping
Slide 26: Sulfur deficiency symptoms in corn
Slide 27: Zinc deficiency symptoms in corn
Slide 28: Corn yield with zinc, Carrington, 2007.*
LSD (0.05) = NS
175 150 125 Bu/acre 100 75 50 25 0
144.2
166.8
158.4
162.8
untreated check PPI zinc sulfate (10 lb/A) zinc seed trts (4) foliar zinc (3)
*zinc soil test = 0.51 ppm (low).
G. Endres and P. Hendrickson
Slide 29: Summary:
Most important nutrients are N and P. Apply K and Zinc if soil test is low. Fertilizer application: • place N in soil
method doesn’t matter
• P, K and Zn favor banding
