Planting corn into bone-dry soils?
After a relatively dry fall and the same conditions through much of winter so far, there's some concern about dry conditions once corn-planting time rolls around in the Corn Belt this spring. So, if you think you might find yourself in these shoes once spring rolls around, what can you do to prepare?
So, what are the chances you'll lose yield potential because of how dry it's been so far this winter? In the state of Iowa, at least, it depends. In the northern areas where soils retain moisture better, dry conditions at planting don't mean a lot; according to Iowa State University Extension agronomist Roger Elmore, from central Iowa north, yield potential only slips 1% in the northeast area while farmers in northwest and central Iowa don't lose any yield potential. That's if the topsoil and subsoil have less than 50% the normal moisture.
On the other hand, Elmore's research shows corn planted in dry soil loses 36% and 30% of yield potential in southwest and southeast Iowa, respectively.
"Another way to think about yield potentials is to look at probabilities of experiencing a year that would provide yield reductions with dry soils at planting," Elmore says. "A median year at NW, SW and SE would result in sizable yield reductions if soils were dry at planting. A 25 percentile year would reduce yields at NE if soils were dry at planting, and only the worst year since 1986 would reduce yields at the Central location."
Find the right hybrid
So, if you're in those areas most susceptible to yield loss because of dry soil at planting, one way to keep that from happening is to plant the right corn hybrid. Look at your soil moisture levels, how well your soil retains that water and what type of hybrid maturity you plant. In 4 out of 5 locations around Iowa, the yield of full-season hybrids wound up higher than early-season hybrids regardless of whether the soil was at half or 100% of its soil moisture capacity.
"It is interesting to note though that in the years where full-season hybrids yielded more than early-season hybrids, the yield advantage was much greater than in the years where early-season hybrids yielded more than the full-season hybrids. This was true at all locations and with both soil moisture scenarios," Elmore says. "Interestingly, yield estimates for early- and full-season hybrids were consistent across both planting situations, whether soils were relatively moist or dry. The probabilities of either of the hybrids performing well were similar whether soils were moist or dry at planting."
One more variable to consider is plant population. If it's dry when you run your planter, should you trim plant populations so those seeds going into the ground can have a greater share of the scarce moisture present? In general, Elmore says his research shows a diminishing return to higher plant populations under dry conditions. In other words, yield potential hits a wall when the soil's dry, regardless of the number of seeds planted.