Crop Maturity And Timely Harvest

11-12CFcvrDr. Steve Brown
Cotton Development Specialist
Dow AgroSciences

Hurry Up!
If there was one factor that I could change in our approach to cotton harvest in the Southeast, it would be to get it done…IN A HURRY. Timeliness preserves yield and quality. But 2013 presents the challenge of picking much of the crop in a timely fashion and, yet, on some late, late cotton, waiting until the last possible moment to pull the trigger.

For both situations, harvest aid applications hinge on crop maturity. Several methods can be used to assess maturity, including percent open boll counts (or observations at 50 mph from a truck window) and NACB counts. But for a final check, I like the cut-boll method. You can safely proceed with termination when the last expected harvestable boll becomes hardened, speckled and difficult to cut with a sharp knife. If you’re persistent with your knife, you’ll see darkening seed coats in cross section, and as you see colors trending from tan to brown, these bolls are considered fully mature. At this stage, harvest aids should have no adverse effects on yield or fiber quality.

Our tendency is to wait too long. We often can get in the field sooner than we might think if we gauge decisions simply on percent open boll. Harvest aids achieve defoliation, boll opening and regrowth inhibition. Combinations are advisable because they deliver increased consistency and allow rate adjustments of each product to match conditions. Don’t discount coffee shop talk as a factor in the decision. You can learn a lot from what your neighbors are seeing in terms of difficulty or ease of defoliation, boll opening and regrowth pressure.

And to reiterate the point about timeliness, if you use an effective boll opener combination that achieves near 100 percent open as quickly as eight to 10 days after application, take advantage of it. Don’t delay!

On the late crop, how far can the mercury fall before we pull the trigger? If we had a crystal ball and knew exactly when that first hard frost – temperatures below 30 degrees – would occur, we would apply a boll opener four to five days beforehand. With a late crop that still has some green foliage, a light frost may actually help turn these leaves and aid defoliation. Following a marginal frost, you can employ a simple smell and touch test. If green bolls are sour or mushy, it’s bad news. If not, you probably should take advantage of any subsequent warming trend to apply aggressive boll opener plus defoliant mixtures.

Some years, cool spells halt boll maturation and it’s over; we might as well treat and pick what we can. In the extreme southerly areas, we’ve seen a rare year in which the crop keeps advancing even after a cold front, and we make cotton late, but that is unusual. As average first frost dates approach, take a hard look at late fields. The right call with an aggressive boll opener can help you get as much as you can…but don’t wait too late.

Click here to ask Dr. Steve Brown a question or submit a comment about this month’s Cotton Consultant’s Corner.

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