The weather has not been very forgiving for Arkansas’ farmers but, fortunately, soybeans are.

Many growers in the Arkansas Delta are waiting for flooded rivers to crest and looking for quick drainage to get back into the fields to plant, replant and do repair work.

“In Arkansas, the soybean crop has the widest planting window compared to the other crops grown in the state,” said Jeremy Ross, Extension agronomist-soybeans, for the University of Arkansas Division of Agriculture. “The standard recommendation for planting soybean varieties in Arkansas is between April 15 and June 30. Planting during the conventional time period from early May to early June usually provides for rapid seed germination and emergence.”

Research suggests that planting after June 15 results in a 1 to 2 percent yield loss per day, with the yield loss potential increasing to 2 to 3 percent per day after July 1 under dry conditions.

Some of the yield loss associated with late planting can be minimized by changes in variety, variety growth habits, herbicide selection, increasing the plant population and decreasing the row spacing to 20 inches or less.

Planting after July 15 is not recommended due to a greatly shortened growing season, although some varieties that require longer maturation periods usually have enough time to produce mature seed before a fall frost if emerged by Aug. 1. Plant height and grain yields will be greatly reduced in July plantings.

Soybean plants are sensitive to the photoperiod, or lengths of daylight and darkness.

“Soybean plants can be especially affected by planting date since it impacts the number of days to flowering, and amount of time available for vegetative plant growth and plant development, which all are necessary for good yields.

“Planting beyond the optimum date will cause yields to be reduced. Planting too late can reduce yields because of poor stands due to excessively hot soil temperatures or because day lengths are too short. Short day length may result in plants flowering early and having reduced vegetative growth.”

For the week ended May 1, soybean planting stalled from the previous week at 14 percent planted. That’s well behind the 23 percent five year average and last year’s 32 percent. Nine percent of the crop had emerged, compared with the five-year average of 11 percent.

For more information on crop production contact your county Extension agent, or visit www.uaex.edu and www.arkansascrops.com.