| Table 1. Potential impact of various management and environments that may alter corn emergence rates. (Source: Adapted from Corn Development, University of Wisconsin) |
| Management/ Environment | Specifics | GDU Adjustment | Sources |
| Residue | % In-row Residue Cover | 5 to 50 GDU | Swan et al., 1987 |
| Soil texture | Fine | Add 30-60 GDU | |
| Coarse | Subtract 30-60 GDU |
| Planting date | Before April | Add 10-25 GDU | |
| After May 15 | Subtract 50-70 GDU |
| Seed-zone soil moisture | Below optimum | Add 30 GDU | Schneider and Gupta, 1985 |
| Seed-bed condition | Soil crusting or massive clods | Add 30 GDU | Schneider and Gupta, 1985 |
| Seeding depth | For each inch below 2 inches ... | Add 15 GDU | Hunter and Kannenberg, 1972 |
| Severe drought or heat stress | Corn will not germinate until it absorbs 30% to 35% of its weight in water. | | Abendroth et al, 2011. |
| Seed treatments | Insecticides and fungicides | These may improve emergence percentage and perhaps emergence uniformity. If they improve plant to plant uniformity, they may hasten overall emergence in conditions listed elsewhere in this table. |
| Hybrid | Hybrids with better emergence scores may emerge faster | Variable | |
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