The following table lists guidelines for harvesting drought-stressed corn under various conditions. Another factor to bear in mind is nitrate accumulation under drought stress. Nitrates will accumulate in the lower part of the stalk, so the cutting height should be at least 10 inches for both silage and hay.
| Table 1. Suggested structures, chop length and screen size for harvesting corn for silage. |
| Dry matter moisture in standing crop |
Usual maturity |
Ideal structure for storage |
Optimum length of cut |
Screen size |
| 70% or more |
Milk stage |
Stack, trench or bunker less than 10' deep |
1/2" |
None needed |
| 65 to 69% |
Early dough to hard dough |
Stack, trench or bunker, more than 10' deep, or upright silo |
1/2" |
None needed |
| 60 to 64% |
Well dented to mature |
Upright structures, or trench or bunker more than 14' deep |
3/8" |
2-1/2 to 3" screen below knives |
| 50 to 59% |
Mature seed o one-half dry stalk |
Very tight upright structures |
1/4 to 3/8", sharp knives |
2 to 2-1/2" screen below knives |
| 50% or less |
Half to completely dry stalk |
Gas-limiting structure |
3/8 to 1/2", sharp knives |
2" screen below knives |
| It appears there is little concern about the nutritional effects of fine chopping for growing or finishing cattle. Silage chopped less than 3/8 inch is satisfactory and gives equivalent gain and efficiency as that chopped at 5/8 inches. However, it takes more energy to chop at 3/8 rather than 5/8 inches. |
