Harvest and End Use

Harvesting of sorghum silage will depend upon several variables, including type of silage production system in use (bunker silos vs. upright silos), growing conditions, feed-value desired, intended use of product, etc. Again, consult with your local area extension agents or consultants on what system is best suited for your situation.

IMPORTANT: Frost dates play a role in harvest times. Typically, producers try to harvest before the first frost, but if this not possible, producers should wait 3-7 days afterwards, or until the plant is dry and ascyanogenic glucosides dissipates to decrease risk of prussic acid poisoning. In a two-cut system, harvest must be delayed after a non-killing frost until re-growth is at least 18 inches tall to reduce the risk of prussic acid poisoning.

Harvesting is typically done with the use of a forage cutter or chopper. A kernel processor may or may not be attached to the chopper. From the field, the chopped silage is moved to a silo. Harvesting decisions may reflect not only storage options and harvesting time, but may also reflect the intended end use of the forage.

Moisture Percentage	Use	Harvest Method
70-80	Wet Silage	Direct Cut
60-70	Regular Silage	Cut and wilted
40-60	Haylage	Cut and wilted
25 or lower	Hay	Cut and allowed to dry

Crop harvest and storage module, New Mexico State University, pg. 4

As noted above, two methods are primarily used for handling high-moisture crops: 1) Direct cut; and 2) Cut and wilt (a cut, wilting in the fields, and pickup). The direct-cut system can be used if moisture content is below 75%; otherwise, it is necessary to reduce the crops moisture content by letting it wilt in the field. This can take anywhere from 2 hours to two days, which reduces the moisture content to 40-50%. A direct-cut method is preferable for harvest, since it involves fewer operations and handling losses tend to be lower.

If silage is cut and wilted, it should be moved into storage using covered wagons (Penn State research). No additives are necessary when forage is wilted to recommended moisture levels [wilting increases] soluble carbohydrates content to a level which will enhance fermentation and preservation (Penn State).

Cut silage is blown into a forage wagon or truck in the direct-cut method and changing knife configurations can control the length of the cut.

Moisture content is also a function of the type of silo used and the following table lists some suggested moistures for different silos.

Type of Silo	Ideal Forage Moisture (%)
Gas-Limiting Silo	40-50
Conventional Upright*	60-70
Bunker or Trench Height, 12 ft or less Height, more than 12 ft	70-75 65-70
Stack* Height, 12 ft or less Height, more than 12 ft	72-77 68-73
*top 2-3 feet should be 70-75% moisture