What is in this article?:
• Since so much is invested in a cotton crop it is absolutely imperative that we protect this investment by taking all precautionary measures to establish an optimal stand with good seedling vigor.
When to replant
Previous research in Georgia suggests that replanting in June may be justified when 3-foot (or greater) skips occupy nearly 50 percent of planted acres, which is quite a substantial loss.
One reason that such a substantial loss is required before replanting is justified is the economics of starting over, therefore it is important to reduce the risks of stand loss by planting when conditions are optimal and protecting seedlings (from insects, herbicide injury, diseases, nematodes, etc.) for several weeks after emergence.
When evaluating a plant stand, take a mental note of stand losses and try to visualize what an optimal stand would look like. If planting 2.5 seed per foot on 36-inch rows, then you would expect to see a stand of approximately 2 plants per row foot.
Comparing the stand losses to an optimal stand could provide insight on how much yield may be lost. Additionally, observing the size of gaps between plants may provide insight regarding potential effects on weed control, maturity and canopy architecture.
When making visual estimations of stand loss, consider gaps larger than 3 feet as multiple gaps to determine the percentage of acreage that is comprised of 3-foot gaps.
For example, if gaps of 6 feet are observed, then it should be considered as two 3-foot gaps. Secondly, evaluate the status or health of remaining plants. If significant thrips, seedling disease, and/or herbicide injury are observed when seedlings are relatively young, then additional yield may be lost, although this varies widely from situation to situation.
Whether or not additional injury is observed in fields with skippy stands, it is always imperative that the remaining stand be protected from anything that could cause additional yield loss or delays in maturity.
If a skippy stand is the result of hail damage, remember that seedlings can generally survive if one or both cotyledons and the terminal are still present in whole (preferably) and sometimes in part, although split terminals and delays in maturity are a common result of hail damage. If both cotyledons and the terminal have been destroyed, yield penalties can be expected.
Also evaluate the strength of the main stalk in hail damaged situations, as hail can typically damage or bruise the main stem and affect the seedlings’ ability to recover and continue to grow. These observations should be made meticulously in order to make the best decision.
Another factor to consider is yield potential of a particular field, based on field history and other factors (soil productivity, irrigated versus dryland, etc.) when deciding whether it is worth the extra effort and expense of replanting.
Additionally, growers must decide whether or not a better stand can be achieved by replanting. Some fields may consistently present a challenge for stand establishment, or moisture may become deficient when growers intend to replant.
In other words, consider the likelihood of obtaining a better stand if replanted. The necessity of replanting can only be determined through extensive evaluation and consideration of all factors.
Although there are factors we cannot control, there are several factors that can be controlled to protect seedlings, so that replanting can be avoided.
For additional information from Georgia research and Extension, see http://www.ugacotton.com/.
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