Corn looks pretty good in Delaware County this year, let’s get it across the finish line with a well-timed harvest to maximize quality. Not that there haven’t been challenges; a few weeks of dry weather and a month or two of rain have all had their effects. We are very near the 15-year average for growing degree days (GDD), and fields are a bit more mature than they may look from the road, so don’t get fooled, looks can be deceiving, the only way to be sure of picking the best harvest timing is to base your decision on whole plant dry matter. The forecast looks favorable for now, but we know from last year what an early frost can do to silage quality.
CCE teamed up with Dairy One, and their portable NIR, to test corn dry matter this week and the results are in the chart to the right. Samples varied from ¾ milk line to ears still in milk stage, but ear stage alone was not adequate to guess dry matter (DM) content. DM is the best way to decide on harvest readiness, because it best predicts fermentation quality. We recommend 32 – 36% DM for bunk silos and bags, 35 – 38% DM for upright silos. Remember proper length of cut, thorough kernel processing, and adequate packing are all critical in making quality corn silage.
The samples of corn tested on September 7th averaged 32% DM with a range of 27% DM to 44% DM. With the help of Dairy One, were able to measure starch content as well, which averaged 31% with a range between 27% and 36%.
As corn matures it will increase in starch content, and increase in yield. Harvesting too early will sacrifice yield and energy content. Harvesting too late will yield poorer fermentation and lower starch digestibility. Corn will mature and dry down at about ½ to ¾ point of DM per day. On the average our samples would be at an ideal DM in 7 -10 days. This could change with warmer/cooler weather, frost, advanced leaf disease damage etc.
Getting DM into the target zone yields best fermentation. Use of reputable inoculants helps on corn silage, especially when it is getting dry. Inoculants containing Lactobacillus Buchneri have been shown to be more effective with corn silage. Increasing chop length with wetter silage may also reduce silo juicing.
Delaware County Corn Dry Matter Results – September 7, 2021
| Town | Ear Maturity | Starch (%DM) | Dry Matter % |
| Davenport | ⅓ milk line | 29 | 31 |
| Davenport | ⅓ milk line | 31 | 32 |
| Davenport | ½ milk line | 33 | 36 |
| Franklin | ⅓ milk line | 31 | 29 |
| Franklin | ⅓ milk line | 29 | 29 |
| Franklin | ⅓ milk line | 31 | 30 |
| Franklin | ¼ milk line | 31 | 32 |
| Franklin | ⅓ milk line | 31 | 33 |
| Great Bend | ¼ milk line | 30 | 30 |
| Hamden | milk | 29 | 31 |
| Kortright | ¼ milk line | 31 | 32 |
| Kortright | early dent | 29 | 33 |
| Kortright | ½ milk line | 32 | 35 |
| Milford | ½ milk line | 37 | 44 |
| Sidney | ½ milk line | 30 | 30 |
| Sidney | ½ milk line | 32 | 32 |
| Sidney | ½ milk line | 32 | 32 |
| Sidney | ¾ milk line | 32 | 32 |
| Sidney | ¾ milk line | 31 | 33 |
| Sidney | ¾ milk line | 36 | 41 |
| Stamford | early dent | 29 | 30 |
| Stamford | early dent | 31 | 33 |
| Stamford | early dent | 32 | 34 |
| Tompkins | milk | 27 | 27 |
| Tompkins | ⅓ milk line | 30 | 31 |
| Tompkins | ¼ milk line | 30 | 33 |
| Tompkins | ½ milk line | 32 | 34 |
| Walton | ⅓ milk line | 32 | 32 |
| Walton | ½ milk line | 32 | 33 |