Determining and Using Cutout

Cutout is a gradual change over 1 to 2 weeks during which vegetative growth ceases. It is the time when blooms currently on the plant have a small chance of surviving to harvestable bolls. Estimating the time over which cutout occurs can be helpful in crop management.

The best method of estimating cutout is to monitor the number of nodes above the highest first position white flower (NAWF). When this value declines to 4 or 5, cutout has been reached. The figure below illustrates the typical relationship between NAWF and weeks after first bloom.

NAWF declines by about one node per week for every week after first bloom. However, the rate of decline may be affected by the use of PGRs, available moisture, or other factors. If stressed prior to bloom, NAWF may be 7.0, but if it rains, that value may stay near 7.0 for several weeks. Typically 4 to 5 weeks of effective bloom are required to produce a high-yielding crop.

While NAWF is helpful in establishing the onset of cutout, monitoring the decline of NAWF is beneficial in management. Cotton fields which are growing with too much vigor this late in the season will end up rank, will not follow this normal rate of decline, and may be subject to problems such as excessive boll rot.

This means vegetative growth is not being reduced by the developing boll load, and an investigation into cause, and possible changes in management are required.

This article is from the Cotton Management Guide, a publication with year-round advice on managing high-yielding cotton. Download the Deltapine Cotton Management Guide now or sign up for new content to be delivered to your email each month.