Current recommendation: Keep the cotton planter parked. Current planting conditions are rated very poor. Heat unit accumulation five days after planting is deteriorating this week and does not improve significantly until near the end of April.
Oftentimes we feel the need to plant as early as possible. Our data shows that we can still optimize yields with delays in planting. Our optimum planting window in southeast Arkansas historically includes dates ranging from April 20 to April 30 (Table 1). Locations at and north of I-40 see their optimum window shifting back as late as May 9. Weather varies from year to year. However, the most important thing is to do it right the first time.
Table 1. Percent of total yield potential by planting date.
Optimum conditions for planting include a mid-morning 68-degree soil temperature at 2 inches for three consecutive days, plus a favorable 5-day forecast. Heat unit accumulation (DD60s) the five days after planting is an excellent guide to evaluate planting conditions (Table 2). Park the planter if DD60 accumulation is predicted to be 15 or less for the 5-day period after planting. Good results are often seen with 25 or more heat units being accumulated during the 5-day period after planting.
Table 2. Temperature guidelines to determine favorability of a five-day forecast.
It is important to start with the best quality seed to increase the chances of getting a good uniform stand if conditions are less than optimum. Remember that as seed size decreases, the importance of having good soil temperatures after planting increases.
Although dependent on growing conditions, a delay in planting early in the planting window can have little impact on the date of flowering, as cotton planted under optimum conditions will often catch up to earlier planted cotton that struggled with cool temperatures. Adequate soil temperature for vigorous plant growth is critical. Make sure adequate soil moisture is available for optimum results and that seedbeds are firm to ensure good seed-to-soil contact.
There are many signals or signs that people use to indicate the right time to plant. Getting off to a good, quick start will pay dividends season long if we do it right the first time.
Bill Robertson is the Extension cotton agronomist for the University of Arkansas System Division of Agriculture.
Πηγή: Cotton Grower