Should double cropping still seem like a sound practice, be aware that wheat is maturing as much as one or two weeks ahead of schedule. Although this could be a nice advantage for double croppers who typically play the odds against a short growing season, soil moisture deficits are still a very real problem. Bill Casady Double-cropping soybeans after wheat is an established practice in the South where the growing season is long enough to support two crops. Although yields in a late season crop of soybeans are generally diminished, the success rate of double cropping soybeans in the South is very good, because of the abundance of warm days and the long growing season. As you move northward the available time for a second crop is squeezed at both ends.
Wheat matures later, which delays the first available date for planting a second crop of soybeans.
And the first killing frost occurs earlier, which will stop an otherwise healthy crop in its tracks leaving green immature beans that will never be suitable for harvest. Double cropping has a reasonable chance for success in Missouri only about as far north as I-70 where wheat is harvested at about the beginning of the last week of June. At this latitude, the first killing frost also occurs by October 4 in one out of ten years, leaving a growing season of only about 102 days, which is adequate, but still a squeeze for a successful soybean crop. The success of a double crop of soybeans as far north as I-70 really depends on the ability to utilize all of that short remaining growing season. Soybeans are sometimes planted in dry soil in April or May with the hope that a rain will bring them up, but moisture must be available immediately to be successful with a crop of soybeans planted in late June.