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Percent stand loss doesn’t matter nearly as much as large skips in the field.

John Hart, Associate Editor

August 15, 2022

5 Min Read
North Carolina State University Extension Cotton Specialist Guy Collins offers guidance on replanting decisions during the Blackland Farm Managers Tour at Southland Farms & Howell Farms in Pantego, N.C. John Hart

Replanting is not uncommon for North Carolina cotton farmers, but the decision to replant or not never comes easy.

Speaking at the Blackland Farm Managers Tour at Southland Farms & Howell Farms in Pantego, N.C., Aug. 3, North Carolina State University Extension Cotton Specialist Guy Collins noted that we may have ideal conditions and great seed quality in some years, but one heavy rain sometime between planting and emergence could necessitate a replant.

Historically, growers looked at stand loss to determine replanting, but Collins noted researchers have found over time that percent stand loss doesn’t matter nearly as much as large skips in the field. North Carolina State’s old replanting recommendations were based on data from Georgia and Louisiana from the early 2000s that if 50% of the planted area is occupied by skips of three feet or greater, then replanting may be justified.

But what has changed since the early 2000s is that seed has become more expensive and companies no longer provide seed at no charge for replanting as they did before a few years ago.

 “Prior to five six years ago, if you needed seed to replant, you just called your seed rep or your dealer and you got another bag. You only paid for it one time. And that’s still the case to a degree,” Collins said at the field day. “But to encourage smarter planting decisions, most of the seed companies have implemented a surcharge for replanting. It differs from company to company. A lot of them charge 25% of the suggested retail price or something along those lines.”

Collins pointed out that in the early 2000s, replanting would typically cost $7 to $8. Today, considering the cost of labor, wear and tear on equipment, as well as the seed cost, replanting can cost $35 or more. “That gets a little bit expensive, so we don’t want to replant, if we don’t have to, but we also want to make sure we do the best we can to get it right the first time.”

One challenge with replanting decisions is determining how well the replanted cotton is going to perform. Cotton farmers need to make sure they are going to get a better stand if they replant, so it’s important to know the reason they had a poor stand the first time.

“The date of that replant, in my opinion, matters quite a bit. We never really know what the year holds for us. Is it early-planted or is it late-planted that the year is going to reward? And that gets very complicated for us in North Carolina,” Collins said.

“If it’s planted on May 25th or before, we tend to think it’s got an equal chance of achieving the highest yield possible based on heat unit accumulation. When we get beyond May 25th, in my opinion when we get on into June with either planting or replanting, that’s when it becomes a little bit questionable,” he said.

Late planted cotton can yield well

In some years, late planted cotton can yield quite well. Collins said if there is a tropical storm or hurricane that causes seedcotton losses, or even a wet and cloudy September that causes a lot of boll rot, early planted cotton will be severely penalized in yield, and late planted cotton will do better.

“In a year like that, June planted cotton tends to shine because you have closed bolls throughout that entire time that open up under usually drier conditions in October or mid-October. But the reverse can happen. In 2020, we had an abnormally cool September and early October, so boll maturation was a big problem. It was very difficult to get this crop to open so we could defoliate it and harvest in a timely manner. In that year, in particular, earlier planted cotton by far outyielded later planted cotton,” Collins explained.

Indeed, Collins said weather remains the million-dollar question and the wild card because it is always unpredictable.

In their work to develop new replanting recommendations for North Carolina cotton, Collins and his team conducted a series of early- and late-planted trials and discovered on average it requires about 30 % of the planted area occupied by three-foot skips or greater to necessitate replanting cotton.

“If we were able to predict what it was going to yield, we could be a lot more precise with that. Sometimes that threshold was 5% to 10% of the planted area in three-foot skips, sometimes it was closer to 50%. But on average, across years, across planting dates, etc., it seemed to be about 30%, so that’s a different threshold of what we’ve been recommending prior to that based on that older data because things have changed,” Collins said. 

In one research project, now complete, Collins and his team worked with North Carolina State Ag Engineer Jason Ward and graduate student, Enrique Pena Martinez, to find a better way of assessing stand loss rather than just simple visual inspection, which requires tedious measurements and can be very time consuming. In the research, Ward used a drone to take an overhead image of the cotton field and then determine a way to calculate whether to replant or not.

 “We used a reference plant that would be the very first plant in the plot, and we were able to develop an algorithm that could count the distance between plant No. 1, that reference plant and the next one and the reference plant to the one after that and so on. That way you could back calculate the size and frequency of three-foot skips ,” Collins explained.

Now that the project is complete, Collins is hoping private industry will pick up the technology and develop the software that will allow a farmer or crop consultant to fly a drone over the field, take an image, calculate percentage of the planted area occupied by three-foot skips or larger, and determine if replanting is necessary.

Finally, Collins said if cotton needs to be replanted, it is best to replant into the already planted cotton rather than destroy what is already planted because there is no guarantee the replanting will work, particularly if it’s replanted after June 1.

“You don’t know what the rest of the season will hold,” he said.

About the Author(s)

John Hart

Associate Editor, Southeast Farm Press

John Hart is associate editor of Southeast Farm Press, responsible for coverage in the Carolinas and Virginia. He is based in Raleigh, N.C.

Prior to joining Southeast Farm Press, John was director of news services for the American Farm Bureau Federation in Washington, D.C. He also has experience as an energy journalist. For nine years, John was the owner, editor and publisher of The Rice World, a monthly publication serving the U.S. rice industry.  John also worked in public relations for the USA Rice Council in Houston, Texas and the Cotton Board in Memphis, Tenn. He also has experience as a farm and general assignments reporter for the Monroe, La. News-Star.

John is a native of Lake Charles, La. and is a  graduate of the LSU School of Journalism in Baton Rouge.  At LSU, he served on the staff of The Daily Reveille.

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