Late Season Cotton Irrigation: What You Should Know

Every year, cotton crops reach their peak flowering period in January. This is a crucial time for maximizing the final product yield and the quality of the fibers, and your cotton irrigation system plays a critical role in the success of your yield. Longer flowering results in more cotton bolls and higher yields.

Usually the cut-out period is late January to mid-February, once the plant reaches 4 to 5 nodes above white flower (NAWF). But some say you should shoot for an 8 or greater NAWF at first flower, and maintain that level as long as possible so long as the season allows. If crops are cut too quickly, they will get stressed, and it will be more difficult to support the development of new fruits.

It’s absolutely critical during this stage to keep up with all regular crop maintenance, including managing moisture, insect levels and proper nutrients.

As you get close to the end

The NAWF for a cotton crop will slow down to a point where it cuts out. When managing your cotton crops, you should avoid a rapid NAWF decline, as this will reduce its yield potential. However, it’s also important to avoid delaying it too much, as this could cause issues with delayed harvests at the end of the season.

Most of the time, you can use the date of the last effective flower as a guide for targeting cut-out dates. There are tools available to help you determine when this date occurs based on your region and other characteristics of your farm. The date of the last harvestable boll can either be determined by temperature or by date. Usually, a crop will be ready for harvest a couple months after the date of the last effective flower.

After cut-out occurs, it’s still important to stay on top of your irrigation management.

The water requirements you have for the end of your season will be determined by an estimation of the number of days until defoliation occurs. You’ll need to predict the amount of water likely to be used over that time period.

The last effective flower will usually take 50 to 65 days to reach full maturity, about five days after the first defoliation. That means that there will be at least 50 days left in the growing season, so you must manage irrigation accordingly and not stress the plant so you can allow the flowers to reach their full maturity.

Once the first boll opens, crop water might be at 5 to 7 mm per day, but this may decline to 3 to 4 mm per day during the final two to four weeks before defoliation occurs. If the roots have grown down to a solid depth at cut-out, the plants can easily extract most of the available water before the final boll reaches maturity.

For more information about the factors you should plan out while considering the late stages of cotton irrigation and growth for your crops, contact B&M Pump Irrigation Sales & Service, Inc. to discuss how we can help bolster your cotton irrigation systems and processes.

Categorised in: Cotton, Irrigation