Cotton strippers are harvesting machines designed to remove cotton bolls from plants quickly across wide fields. They are especially useful in regions where cotton plants are shorter, drier, and more uniform at harvest time. Instead of picking only the fluffy lint from open bolls, a stripper removes much of the boll and nearby plant material too.
This makes the machine fast and efficient, but it also means the crop must be cleaned carefully before storage or ginning.
A modern cotton stripper uses rotating brushes, bats, or rolls to pull cotton bolls from the stalks as the machine moves down the rows. The harvested mixture is carried by conveyors and airflow into cleaning units that separate some leaves, sticks, burs, and dirt from the seed cotton. Cleaned seed cotton is then collected in an onboard basket or compacted into a module for transport.
The physics involves contact forces, rotation, airflow, separation by size and density, and power transfer from the engine to the harvesting and cleaning systems.
Key Facts
- Field capacity = harvested area / time, often measured in acres per hour or hectares per hour.
- Forward speed affects harvest rate: higher speed can increase acres per hour but may reduce cleaning quality or increase crop loss.
- Stripper heads remove cotton by mechanical contact forces from rotating brushes, rolls, or bats.
- Power = force x velocity, so moving and rotating machine parts require more power when load or speed increases.
- Airflow helps separate lighter leaves and trash from denser seed cotton using differences in drag force and weight.
- Harvest efficiency = harvested cotton / total available cotton x 100%.
Vocabulary
- Cotton stripper
- A harvesting machine that removes cotton bolls and some plant material from cotton stalks using mechanical stripping parts.
- Seed cotton
- The harvested mixture of cotton fiber and seeds before the fiber is separated from the seeds at a gin.
- Stripper head
- The front harvesting unit that contacts cotton plants and pulls bolls from the stalks.
- Field capacity
- The rate at which a machine can cover and harvest a field, usually measured as area per unit time.
- Trash
- Unwanted plant material such as leaves, stems, burs, and dirt mixed with harvested cotton.
Common Mistakes to Avoid
- Confusing a cotton stripper with a cotton picker is wrong because a picker removes mostly lint from open bolls, while a stripper removes bolls plus more plant material.
- Assuming faster travel always improves harvesting is wrong because too much speed can leave cotton in the field, overload the cleaning system, or increase trash in the harvested crop.
- Ignoring plant condition is wrong because cotton strippers work best when plants are dry and mature, and wet or green plants can clog the machine and reduce cleaning performance.
- Treating cleaning as a perfect separation is wrong because onboard cleaners reduce trash but cannot remove all unwanted material before ginning.
Practice Questions
- 1 A cotton stripper harvests 96 acres in 12 hours. What is its field capacity in acres per hour?
- 2 A machine harvests 18,000 kg of seed cotton from a field that had 20,000 kg available. What is the harvest efficiency as a percent?
- 3 Explain why a cotton stripper may need more onboard cleaning than a cotton picker, using the difference between stripping bolls and picking lint.