Nebraska’s ’09 dry bean harvest likely to drag on for weeks; late beans will race first frost
Western Nebraska's 2009 dry edible bean harvest season is likely to drag on for weeks longer than most years, and in areas where planting was late, it will be a race between harvest and first frost, according to a University of Nebraska-Lincoln Extension Educator.
Harvest could begin anywhere from early September until late October, depending on when a field of beans emerged, how much stress the bean plants have experienced, and the daily high and low temperatures between now and harvest. In addition, the 2009 crop is likely to experience some quality issues.
This was the assessment offered by University of Nebraska-Lincoln Extension Educator Jim Schild, who spoke at the 2009 Dry Bean Field Tour on Aug. 18 at the UNL Panhandle Research and Extension Center. The event is co-sponsored by the Nebraska Dry Bean Growers Association.
The 2009 dry bean crop has been challenged by late planting dates in some areas, cool and wet weather across western Nebraska, and localized hail damage.
Dry edible beans reach maturity and are ready to harvest after they have received a certain number of growing-degree days (GDDs). GDDs are calculated by a formula that includes the daily high and low temperatures during the growing season. So a typical July day with a high of 90 and a low of 60 generates 22.5 growing degree days. But a cool day, with a high of 75 and a low of 50, generates 12.5 GDDs.
Most common great northern bean varieties require anywhere from 1,550 to 1,700 GDDs under non-stress conditions, which translates into growing seasons of 83 days to 90 days. But if young dry bean plants experience stress early in the growing season, as they have in 2009, maturity will be delayed, Schild said. Stress adds 150 to 250 GDDs and seven to 12 days to the maturity date, pushing back harvest accordingly.
In the North Platte Valley, the number of GDDs that dry beans have experienced in 2009 depends on when they emerged. And there was a wide variation in planting and emergence dates, thanks to cool, wet weather early in the growing season that kept farmers out of the fields for several weeks in some areas.
As of mid-August in the Scottsbluff area, beans that emerged on June 1 had received 1,343 GDDs; June 10, 1,251; June 20, 1,120; June 30, 916; and July 10, 725.
The bottom line? Depending on their emergence date, as of mid-August most dry beans in the Scottsbluff area still required 357 to 975 GDDs until maturity. Depending on whether days are warm or cool, it will take anywhere from 18 to 65 days (from mid-August) to accumulate that many GDDs.
So, depending on the weather, Schild projected that likely start-of-harvest dates would vary as follows, for each emergence date:
June 1: Sept. 3 to Sept. 9;
June 10: Sept. 7 to Sept. 15;
June 20: Sept. 14 to Sept. 25;
June 30: Sept. 24 to Oct. 6;
July 10: Oct. 3 to Oct. 18.
"So it's safe to say we'll have a fairly long dry bean harvest in 2009," Schild said. "When's the frost going to come? That's the million-dollar question."
The Panhandle Research and Extension Center website is at www.panhandle.unl.edu.