Cotton is a valuable commodity this fall and prices look good for the 2011 season, leading many growers to look for ways to reduce costs to take full advantage of the pricing options for next year’s crop.

Two research projects under way at the two primary cropping research stations in South Carolina are geared to helping cotton farmers, and in some cases peanut and soybean growers, cut some costs without sacrificing valuable yield or quality for the 2011 crop.

Cotton growers in South Carolina and southeastern North Carolina continue to battle ever-increasing numbers of glyphosate and ALS resistant weeds — Palmer amaranth being the major nemesis.

Pre-emerge and at-planting materials are highly dependent on the weather and somewhat dependent on soil type. Once pigweed are up and growing much over 3-4 inches tall there are few options for cotton growers, if their pigweed are resistant to glyphosate.

One way to help manage these weeds, which have been dubbed Super Weed by some, is to plant narrow rows. Whether cotton will perform well in narrow rows in the Southeast is far from a certainty, but Clemson University researchers Mike Jones and Will Henderson are taking a look at a 7.5 inch row spacing system at the PeeDee research station and at the Edisto Agricultural Research and Education Center in Blackville, S.C.

Twin-row, narrow spacing in corn and soybeans has shown some significant yield increases and some cost reduction in seed. Along with the high value of cotton expected in 2011, likely will come a high cost of seed, so twin-rows on a narrow spacing is one way to save some money on seed cost.

“The big question is whether we can grow narrow row cotton in the Southeast,” says Jones. There is a lot of interest among farmers, so we put in tests at two locations to look at several different soil types and slightly different growing conditions,” he adds.

“If we can grow cotton on narrow rows or twin-rows it should add some earliness to the crop and give the cotton plants a better chance to close early and shade out pigweed,” Jones adds.

In tests at the Florence research center is single 38-inch row cotton with plant populations of 10,000 to 60,000 per acre. In comparison the Clemson researcher planted two 7.5 inch twin-rows on a 38-inch bed, with a 30-inch spacing between rows.

Similar tests conducted in Arkansas back in 2007 and 2008 showed little difference in yield between 38-inch rows and twin 7.5 inch rows planted on the same 38-inch raised bed configuration. Although this experiment indicated that cotton can be successfully produced with alternative seeding patterns, it should be noted that yields were not increased compared to traditional, single 38-inch rows. Also, the data showed little to no differences in cotton growth and yield across a wide range of seeding rates.

Larger tests under irrigation

Will Henderson is looking at a similar test, but his plots are larger and are under irrigation at the Blackville location.

“When we put in a high rate of seed in these narrow rows, we got a lot more top growth and rank growth than in the standard 38-inch row. We will see what seeding rate looks better in the narrow rows,” Henderson says.

Once cotton is harvested later in October, the Clemson researchers will analyze data from yield monitors and evaluate quality factors to determine how the narrow row planting fared with conventional 38-inch row spacings.
In tests across the Cotton Belt ultra-narrow-row (less than 10 inches) cotton has saved growers from $100-300 per acre. Much of the savings come from reduced tractor and picker costs, since narrow rows generally require stripper harvesting. Whether or not the narrow row, twin-row cotton Jones and Henderson are planting can be picked rather than stripped remains to be seen.

Ultra-narrow-row cotton typically requires 80,000-120,000 plants per acre. The narrower the row of cotton, the more columnar or slender the plant tends to be. Limbs tend to be very short and the majority of the cotton is set at the first position with a few second position bolls and typically no bolls at the third position on a fruiting branch.

Though Henderson notes rank growth on the twin-row, narrow row cotton he planted at the Blackville Station, height of narrow row cotton is typically 24-30 inches, further reducing costs by reducing the need for plant growth regulators.

Glyphosate tolerant crops may be the single most significant scientific breakthrough in farming, but over-use of this family of herbicides and natural biological progression of prolific weeds has placed many growers, especially cotton growers, in the Southeast in the position of having to spend a lot of money to control a number of weeds that have resistance to glyphosate.

Palmer pigweed is the most oft-cited, but by far not the only weed that has developed resistance to glyphosate. Marestail or horsenettle, Italian ryegrass and giant ragweed are all as problematic in some fields in some areas of the country.

Major weed hurdle

However, throughout South Carolina and well into east-central North Carolina the major weed hurdle to growing most any crop is Palmer amaranth. A vigorous, rigorous and costly system of over-lapping residual herbicides has shown some success in managing these prolific weeds in cotton, but many of these materials aren’t available on peanuts and soybeans.

For controlling pigweed and other tall growing weeds in peanuts and cotton, growers have used wick bars, often referred to as “Dixie wicks”. The problem with a wick bar is that it only wipes one side of the plant.

Clemson weed scientist Mike Marshall has tested a new machine that is essentially a carpet roller mounted on a steel drum. Herbicide is pumped onto the carpet, which coats the taller weed without damaging the target crop.

Unlike a wick bar or wick rope, the carpet roller pulls the weed in and wipes it on both sides. It also allows herbicides to run down into the plant without dripping on the crop.

“The rates we’ve used are 50 percent gramoxone or paraquat and 50 percent water solution. A big advantage is that you are killing the top of the weed where seed production takes place, and with Palmer amaranth this is a big advantage because these weeds are such prolific seed producers,” Marshall notes.

Marshall says test results, using a research scale model of the commercially available machine has been good. He adds that a few farmers in South Carolina, who have used the commercial version of the machine, have indicated having excellent results in controlling weed escapes in soybeans and peanuts.

The cost of the commercial version of the carpet roller is approximately $20,000 and up, depending on what type pump and other equipment is added on to the roller.
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