1. Soybean Plant Population. How Low Can We Go?

2. Introduction  Recent research indicates we may be planting higher populations then necessary Improved varieties Improved stands  Current recommendations:

3. 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

4. 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’

5. Methods  Planted May 24  Variety NK S43-B1 Indeterminate RR Cruiser Max

6. 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

7. Data Collection  Stand counts made at V4-V5 stage Several locations averaged within each strip  Harvested November 3

8. Results: Stand Establishment

9. Results: Did planter affect yield? a a a a

10. Results: Did population affect yield? a a a

11. 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

12. 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

13. 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

14. QUESTIONS ON THIS?