Transcript Soybean Plant Population. How Low Can We Go?
Soybean Plant Population. How Low Can We Go?
Introduction
Recent research indicates we may be planting higher populations then necessary Improved varieties Improved stands Current recommendations:
Objectives
To evaluate the effects of “lower than optimal” plant populations on soybean yield To evaluate the effects of these populations across different row spacings and planting units
Methods
Study conducted at John Hoffman’s near New Hope Experimental Design: Split-Strip Plot Three populations 160,000 120,000 80,000 Four planting tools Kinze 3500 (15”) Kinze 3500 (30”) Sunflower 9412 (15”) Sunflower 9412 (7.5”) Three replications Strips were 20’ x 300’
Methods
Planted May 24 Variety NK S43-B1 Indeterminate RR Cruiser Max POP 2 POP 1 POP 3 1 301 2 302 3 303 4 304 1 305 2 306 3 307 4 308 1 309 2 310 3 311 4 312 POP 2 POP 1 POP 3 1 201 2 202 3 203 4 204 1 205 2 206 3 207 4 208 1 209 2 210 3 211 4 212 POP 1 POP 2 POP 3 1 101 20' 2 102 20' 3 103 20' 4 104 20' 1 105 2 106 3 107 4 108 1 109 2 110 3 111 4 112
Methods
Fertilizer Program 1.5 ton litter pre-plant Chemical Program PRE: 1 qt RU O-max; 0.125 qt Alliance POST: 1 qt RU O-max; 0.125 qt Alliance; 6 oz Select (volunteer RR corn); ½ qt crop oil Field was irrigated
Data Collection
Stand counts made at V4-V5 stage Several locations averaged within each strip Harvested November 3
Results: Stand Establishment
PLANTER
30" Kinze 15" Kinze 15" Sunflower 7.5" Sunflower
AVERAGE:
30" Kinze 15" Kinze 15" Sunflower 7.5" Sunflower
AVERAGE:
30" Kinze 15" Kinze 15" Sunflower 7.5" Sunflower
AVERAGE: TARGET POPULATION
80000 80000 80000 80000
80000
120000 120000 120000 120000
120000
160000 160000 160000 160000
160000 AVERAGE POPULATION*
61333 64000 62333 70000
65444
94667 103333 84333 82000
84333
111000 132667 129667 124667
124500 DIFFERENCE FROM TARGET
18667 16000 17667 10000
14556
25333 16667 35667 38000
35667
49000 27333 30333 35333
35500 PERCENT DIFFERENCE
23.3% 20.0% 22.1% 12.5%
18.2%
21.1% 13.9% 29.7% 31.7%
29.7%
30.6% 17.1% 19.0% 22.1%
22.2%
Results: Did planter affect yield?
Effects of Planter Type on Soybean Yield
60 50 40 30 20 10 0 a 15" Kinze a a a 30" Kinze 15" Sunflower
Planter/Drill
7.5" Sunflower
Results: Did population affect yield?
Effects of Soybean Population on Yield
30 20 10 0 60 50 40 a a a 64,000 91,000
Plant Population (plants/acre)
125,000
Discussion
No difference in yield b/w 64,000 to 125,000 plants/acre!
Planter type had no affect on final plant stands No difference in yield b/w planter types
Discussion
Can we really get away with 64,000 plants?
I would be cautious Exceptional site Irrigated site Excellent variety Stand uniformity was there What about 100,000 plants?
I think this would work Must get good seed placement, no room for error
What’s Next
Examine effects for different growth habits Bushy vs tall beans Canopy closure is critical for lower population Do not recommend for DC beans Examine effects without irrigation