1. EFFECT OF DELAYED EMERGENCE ON CORN GRAIN YIELDS
Kyle Don Lawles
Plant and Soil Science Department
Oklahoma State University
2006

2. Literature Nielsen, 350 production sites Indiana and Ohio
16% PSV of three inches or less
60% PSV of three to five inches
24% PSV of six inches or greater
For every one inch of PSV about 157 kg ha-1 of yield loss occurred.
Nafziger, delayed emergence can reduce grain yields by 6-22%.

3. Regardless of yield level, plant-to-plant variability in corn grain yield can be expected and averaged more than 2765 kg ha-1, 40 bu/ac(46 transects harvested by plant in Argentina, Mexico, Iowa, Nebraska, Ohio, Virginia, and Oklahoma) Agron. J. 97:1603
40 bu/acre difference between each plant

4. Factors causing delay emergence
Irregular planting depth
Seed spacing
Limited Moisture
Double Seed Drop
Wheel compaction
Seed Geometry
Surface Crusting
Insect Damage
Variable Surface Residue
Variable Furrow Closure

5. Objectives
To determine corn grain yield reduction as a function of interplant competition arising from delayed emergence
II. To evaluate yield levels associated with 3 plant sequences, with and without delayed emergence.

6. Methods Lake Carl Blackwell - Irrigated (LCB) Efaw –Rainfed
Pioneer (33B51) plants/ha
76 cm row spacing (30 in)
17.8 cm between plants (7 in)
0, 2, 5, 8, and 12 days delay
Fertilizer
0 kg N ha-1
50 kg N ha-1
150 kg N ha-1

7. X X X X O X Delayed row Border Row Border Row X – Planted same day
O – Planted delay, days
(0, 2, 5, 8, and 12)
3 Plant sequence

8. Planting device

9. Planting device

10. 2 day delay

11. 5 day delay

12. 8 days delay

13. 12 day delay

14. X O X

15. X O X

20. Conclusions Delayed emergence reduces corn grain yields
Greater than 5 days delay - significant yield reduction (homogeneity of plant stands)
There was a linear reduction in yield with each day of delayed planting
Plants delayed by 2,5, and 8 days continued to compete with border plants. By 12 days these plants competed less with border plants.

21. Thank you