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Recent Weather And The Need To Evaluate Plant Stands

May 12, 2015

By Guy Collins

Tropical Storm Ana brought noticeable rainfall across the majority of the Coastal Plains over the last couple of days.  Reports thus far range from 0.5 inches to nearly 5 inches depending on geography.  This will likely slow planting progress for a couple of days, however soil moisture in several areas was rapidly depleting in some fields towards the end of last week.  Therefore these recent rains could help recently planted cotton to emerge and activate residual herbicides, or at the very least, provide a source of moisture for planting in the remaining acres.  Thus far, we have had very good planting temperatures and soil moisture, so we can’t complain too much.

In some areas, Ana did bring some intense rains.  This could be problematic for cotton that had been recently planted but not yet emerged.  However, there is no reason for panic yet as we have some time for reaction, and plenty of time for replanting.  At this point, growers can likely avoid having to replant most acres if action is taken in a timely manner.

Over the next couple of days, it will be important for growers to frequently monitor fields that have already been planted but not yet emerged, to evaluate progress towards emergence.  In cases where significant and intense rainfall was experienced, and/or if fields have had a history of crusting, then light crust busting or rotary hoeing may be necessary.  Usually, this practice is done when poor stands are noticed and is usually too late to help seedlings emerge or damages the few seedlings that have emerged.  If you wait past 3-4 days past germination (not necessarily planting), you have probably waited too long. If a hard crust is evident when the seed sprout is approaching one inch long, you should break the crust quickly. You only have one or two days depending on soil temperature. The germination process can move so fast in warm soils that the root will grow enough to anchor the seedling between the time you make the decision and the time you actually get into the field. Otherwise, the seedling will spend too much energy while pushing against the crust trying to emerge. This is evidenced by a swelling of the stem below the cotyledons.

Crust busting is best accomplished by running a rotary hoe just deep enough to break the crust completely. No more than 10-20 percent of the seedlings should be completely uprooted or broken off. Pull seedlings gently to determine if they are anchored enough to survive. Crust busting can also be accomplished with a rolling cultivator set with the gangs turned to run straight down the row. Preferably, the gangs should be moved in so that one runs on each side of the row with about a four inch gap.

In our current situation, growers have a good opportunity to avoid stand problems by rotary hoeing or crust busting as soon as surface soils begin to dry out and the crust begins to forms.  Delaying this practice for several days diminishes the likelihood of achieving optimal stands, therefore quick action could offset many problems and the need to replant.

Source:ncsu.edu