Is your corn ready? Planting was staggered this year and maturities are following suit.
Sixty days, that’s the length of time, on average, that it takes for corn silage to mature from silking (pollination) to black layer (physiological maturity). We use 1/2 milk line as the indicator to start checking whole plant moisture.
This year dry matter measurements are running dryer than milk line would typically indicate. At 1/4 milk line, DM measured 65% which we would normally expect at 1/2 milk line.
Seventy percent moisture is the long-term accepted target for beginning harvest, but consideration needs to be given to your farm storage. It’s a fine balance to achieve a DM where you can pack well while preserving maximum nutrients. Bunk silos pack better at the top of the range, while uprights may have excessive seepage above 68% moisture (see Table 1). Nutritionists are also encouraging targeting higher dry matters to increase starch levels.
Table 1. Target Corn Silage DM Levels for Vertical Silage Systems | |
Oxygen Limiting Structure | |
Corn Silage | 40-65% DM [35-60% moisture] |
Conventional Concrete & Stave Structure | |
Corn Silage | |
Under 60 feet | 32-36% DM [64-68% moisture] |
Over 60 feet | Increase 2% DM per 10 ft vertical height |
Source: Mike Hutjens, University of Illinois, Urbanahttp://qualitysilage.com/wp-content/themes/twentyten/PDF/TowerSiloManagement.pdf |
Whole plant dry matter samples will run 2 – 3 points above actual field conditions (aka field will be wetter). Knowing the maturity of your crop and how many days or weeks it takes to harvest allows you to target the moisture for beginning harvest (see Table 2). Moisture will decrease by 0.5 – 1.0 points per day, depending on the weather conditions.
TABLE 2. Influence of Corn Maturity on Grain Yield, Whole Plant Silage Yield, and Moisture Content | ||||||
% Max Yield |
% Moisture |
|||||
Maturity Stage | Avg cal Days To Maturity |
GDU to Maturity |
Grain |
Whole Plant |
Grain |
Whole Plant |
Silk |
50-55 |
1100-1200 |
0 |
50-55 |
— |
80-85 |
Blister |
40-45 |
875-975 |
0-10 |
55-60 |
85-95 |
80-85 |
Late Milk |
30-35 |
650-750 |
30-50 |
65-75 |
60-80 |
75-80 |
Early Dent |
20-25 |
425-525 |
60-75 |
75-85 |
50-55 |
70-75 |
Full Dent (1/2 Milkline) |
10-15 |
200-300 |
90-95 |
100 |
35-40 |
65-70 |
Blacklayer |
0 |
0 |
100 |
95-100 |
25-35 |
55-65 |
Assumes 20 GDU/day to maturity.Adapted from Carter, P.R. 1993. Pioneer Hi-Bred International, Inc. |