What's in your cotton?

Missouri Bootheel cotton fields could use more wheat and less plastic, according to Missouri Extension cotton specialist Bobby Phipps.

The importance of a wheat cover crop in the region was especially significant in 2000, one of the worst sand-blowing seasons ever. Wind-blown sand can literally shear off young cotton seedlings at ground level. But sometimes, wind by itself can whip seedlings around, causing injury and providing openings for seedling disease.

Wheat seeded in the middles definitely provided a refuge from the wind for cotton seedlings last year, according to Phipps “The inter-planted wheat is the only way to go. You look around here last year. Any field that had wheat in it looked better than wheat that didn’t have it.”

Wheat can also have a warming effect on the young seedlings, according to Phipps. “When that wheat is dead and it’s a beige color, it reflects a lot of light and heat down into the canopy. I think that helps the plants grow. It’s cold at that time and the plant needs all the light it can get.”

The specialist adds that the wind really doesn’t blow all year in Missouri. But it does blow a lot in May, “the one month we don’t need it.”

Apparently, the wind is blowing more than just sand around cotton fields, according to Phipps. Textile mills are complaining, and in some cases not buying cotton from certain regions because of plastic bag contamination.

There haven’t been reports of the bags causing problems in Mid-South cotton just yet, but there could be. Phipps said the bags find their way into farmers’ fields and then into modules of cotton. The bags go through the gin and textile mills and have even ended up in finished apparel.

“One thing that I would really like to emphasize this fall is to watch for those Wal-Mart bags in your fields. It’s almost humorous, but it’s dead serious. One mill in the east quit buying cotton in Georgia and the Carolinas because of it.”

It’s not entirely fair to just blame Wal-Mart, since there are lot of stores using plastic bags, notes Phipps. And litterers aren’t always to blame either. “In the East, they have hurricanes that blow the bags around.

“But this is something that we all need to be conscious of. Don’t think that once you get cotton in a module you’re through with it. It could cost you a customer.”

Phipps also recommended using cotton string to tie down module covers. “If it does get into the bale, it’s going to dye and handle like cotton fibers. Also, when you buy the spray markers for your module, be sure to get a product that does not become a contaminant.”

Some Bootheel cotton producers have been using a highly accurate micronaire-testing program to optimize defoliation timing. The program was developed by Arkansas plant breeder Hal Lewis. Phipps offers the micronaire testing service to growers.

To start, growers take samples from the bottom-four positions on the plant. Phipps runs the micronaire through a laboratory set up at the Delta Center. “You plug the micronaire into a chart which tells you at what percent you need to defoliate the crop.”

The method helps the grower walk a fine line between micronaire discount and yield, according to Phipps. “You need to get the micronaire as close to a 5.0 as you can. It’s like playing blackjack. You don’t want to go over. You want to get as close as you can without exceeding that.”

Lewis’ program has been “right on target,” according to Phipps, doing an even better job than monitoring programs like nodes above cracked boll and programs based on DD-60s.

Phipps said Bootheel cotton producers grew a high micronaire crop in 1999, a real dry year, but have since learned to irrigate during bloom to maximize fiber length.

It’s good to remember that the length of the fiber is established during a three-week period after bloom, noted Phipps, so it’s important not to let the plant stress for water during that period, or you could end up with short fiber. Then when you irrigate later or have a later rainfall, you end up packing a lot of cellulose into the shorter receptacle, in effect creating short, fat fibers, i.e., high micronaire.

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