Harvest · September 2025 · 5 min read
Proper defoliation timing is critical for cotton harvest efficiency and fiber quality. Applying harvest aids too early sacrifices yield from immature bolls, while waiting too long risks weathering and bark contamination. Getting the timing right starts with monitoring open boll percentage and nodes above cracked boll.
The standard trigger for defoliation is when 60% or more of bolls are open. Confirm timing by counting nodes above cracked boll (NACB)—defoliate when NACB reaches 4 or fewer. At this stage, remaining bolls are mature enough to open after defoliation without significant yield loss.
Scout multiple areas of the field because maturity varies with soil type, drainage, and planting date.
Common defoliant options include thidiazuron, tribufos, and ethephon. Thidiazuron-based products are effective in cooler temperatures, while tribufos works best when nighttime lows stay above 60°F.
Clean and inspect picker spindles before the season begins. Worn or missing spindles reduce picking efficiency and leave cotton in the field. Adjust row sensors, moistener pads, and ground speed based on crop conditions. Damp cotton early in the morning picks poorly and wraps, so wait until dew has dried.
Run the picker at a speed that maintains full drum engagement without plugging. Typical ground speed is 3–4 mph depending on yield.
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