Corn Stand Establishment Jeff Coulter, Ph.D. Extension Corn Specialist jeffcoulter@umn.edu z.umn.edu/corn 1
Overview Hybrid selection Row width Planting rate Planting date Stand establishment 2
Hybrid selection is critical 3
Crookston, MN (62 118 entries/year) 4
Hybrids longer than 79-day have yielded more Crookston, MN (2006-2012) 62 118 entries/year 5
Hybrids longer than 85-day have been wetter Crookston, MN (2006-2012) 62 118 entries/year 6
Growers are adopting higher planting rates Optimum planting rates tend to be greater in high-yield environments No or little yield penalty for too high of planting rate High planting rates can capture potential yield increases in favorable growing seasons 7
Planting rate affects yield components Yield = (plants/acre)*(kernels/plant)*(kernel weight) 17 23 29 35 41 47 Planting rate (1,000 seeds/acre) 8
Shorter-season hybrids progress quickly through vegetative stages & are more sink limited Lee & Tollenaar, 2007 (Crop Science) 9
From DuPont Pioneer s planting rate estimator for 150 200 bu/acre yield 10
Narrow rows may reduce plant-to-plant competition & increase yield, especially with higher planting rates 30-inch rows 47,000 seeds/acre 22-inch rows 47,000 seeds/acre 11
16 trials with 5 6 planting rates 12 trials in 2013 2015 3 hybrids (74-, 80-, 86-day) Row width varied among trials 4 trials in 2010 2011 2 row widths (22- vs. 30-inch) 3 hybrids (80-, 85-, 89-day) With J. Buckley, N. Johnson, R. Severson, H. Person, R. Nelson, & P. Glogoza (U of M Extension), & NDSU 12
LSD (0.10) 13
LSD (0.10) 14
$3.50/bu $0.045/point/bu LSD (0.10) 15
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No relationship between hybrid performance & region, except with 89-day hybrid 74-day maximized yield in 5 of 11 trials; max. yield in these 5 trials was 103 170 bu/ac 74-day among most profitable in 6 of 11 trials; not individually related to rainfall, yield level, or moisture 86-day out-yielded 74- & 80-day in 4 of 11 trials; max. yield in these 4 trials was 174 196 bu/ac 86-day more profitable than 74- & 80-day in 2 of 11 trials 18
Yield & optimum planting rate were greater with 22-inch rows in 1 of 4 trials Polk County, 2010 14 21 28 35 42 49 Planting rate (1,000 seeds/ac) 19
Optimum planting rate Was greater with 22-inch rows in 1 of 4 trials Did not differ among hybrids in 16 of 16 trials 20
LSD (0.10) 21
$3.50/bu $280/bag LSD (0.10) 22
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In 2 of 3 trials where 23K maximized yield, max. yield was 102 134 bu/ac In 5 of 6 trials where 29K maximized yield, July + Aug. rainfall was 1.3 3.2 Greater yield with 41K than 35K in 2 of 16 trials; max. yield in these 2 trials was 184 216 bu/ac 47K out-yielded other rates in 1 of 16 trials; max. yield in this 1 trial was 220 bu/ac Planting rates as great as 47K never reduced yield, even when drought & low yield 24
Optimum planting rate varies with yield level 25
Optimum planting rates are greater in higher-yielding environments With each 10 bu/acre increase in yield level, optimum planting rate increased by: 780 seeds/acre (eastern Dakotas, 1998 2002) 840 seeds/acre (Illinois, 1991 1994) 990 seeds/acre (Illinois, 2005 2008) 26
Identify areas where stand establishment losses are greater than normal 5% over-planting is common, but may need to be modified for certain conditions or field locations Take stand counts to verify stand establishment losses in various locations of fields Pay attention to areas with poor drainage & abundant residue 27
Plant population map for a field planted uniformly at 30,000 seeds/acre From DuPont-Pioneer 28
Planting date trial at Morris, MN Photo in mid-june April 20 May 19 29
1988 2003 data from Bruce Potter & Steve Quiring 30
Nodal roots = important from V3 until maturity Photo: Iowa State Univ. Seminal roots (temporary seedling roots) = of little importance by V6
Planted when too wet Poor seed-to-soil contact Sidewall compaction Photo: E.D. Nafziger (Univ. of Illinois) 32
Uniform emergence is critical 2 leaf stages behind Photo: E.D. Nafziger (Univ. of Illinois) 33
Plant that was 2 leaf stages behind is late to silk 34
Characteristics of late emerging plants... Silk later = more vulnerable to moisture stress Smaller root system, stalk, & ear Greater stalk & root lodging Lower yield Greater harvest losses Greater harvest moisture 35
Southwestern MN (32,000 plants/acre) Ford & Hicks, 1992 (Journal of Production Agriculture) 36
Uneven moisture in the seed zone #1 cause of uneven emergence Result of Variable soil conditions Photo: E.D. Nafziger (Univ. of Illinois) Tillage & residue patterns Uneven planting depth 37
Take home points Hybrid selection: wide range in yield levels common Hybrid maturity: mid-maturity hybrids often optimize yield & balance risk Planting date: yield potential declines rapidly as planting delayed beyond mid-may Row width: modest yield increases (~5%) possible with narrow rows, but inconsistent 38
Stand establishment: Take home points Vigorous nodal roots are critical Uniform emergence is critical Within-row plant spacing has limited effect on yield if enough plants & if gaps not too wide 39
Take home points planting rate Optimum planting rate increases by 800 1,000 seeds/ac with each 10 bu/ac increase in yield level Optimum planting rate did not vary among 3 hybrids of differing RM in 16 trials in NW MN Maximum net return in NW MN achieved with: 29K seeds/ac in 11 of 16 trials 35K seeds/ac in 10 of 16 trials 41K seeds/ac in 6 of 16 trials Planting rates as great as 47K seeds/ac never reduced yield 40
Take home points Increases in corn yield are limited in frequency & magnitude with above-normal planting rates Weather can have a much larger impact on yield than agronomic inputs Have a Plan B & Plan C in case the weather causes challenges 41
Be an economist, pay attention to details Control costs without impacting yield Conduct simple on-farm tests to evaluate inputs Be timely Don t overlook the basics Crop rotation Hybrid selection Stand establishment Weed control 42
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