There's a tendency among growers to plant full season crops if they are able to plant early. Alternatively, if growers have to plant late, it seems natural to plant shorter-maturity varieties.
A Kansas State University agronomist suggests, however, that farmers consider mixing it up a bit by planting some acreage to slightly shorter-season varieties even if they're planting early, or consider a longer-season variety if they plant a little later.
"Now that's kind of opposite of what people would think, but if you do it the other way, where you plant full season varieties early and a short-season variety late, they end up flowering and having their critical time at the same time," said Dale Fjell, crop production specialist with K-State Research and Extension. That can drop yields if high temperatures or other adverse weather sets in at that critical time.
"It's all about reducing risk. If we look back at the last 10 years, we've been planting earlier and earlier every year. We've had pretty good success with that, but last year we saw reversals of that success," he added.
Many of the later-planted crops were able to withstand the summer drought and when rain and cooler weather arrived, they recovered, he said. But earlier-planted crops fared worse last year because they were flowering or pollinating right in the middle of the extreme heat.
Because no one can accurately predict when or if extreme heat – or other weather factors – will come into play, Fjell suggests that growers spread risk by either mixing their planting dates or vary the hybrid varieties they use, with an eye to maturity dates.
For example, soybean growers in southeast Kansas usually use Group V [full season] varieties and plant in May. "But in the past few years we've [K-State] been looking at planting early-maturity Group IIs or IIIs in April," the agronomist said. "That's allowed for those plants to get some height before they flowered and set pods, and they were ready to harvest in late August or early September. That really allowed for that critical time [flowering] to be different than in our later full-season varieties. By doing some of each – planting early with early-maturing varieties, and planting some later with fuller season, you've spread out the critical times."
Fjell said that there may be some yield sacrifice by planting shorter-season varieties, compared with planting higher-yielding full season crops. However, studies indicate that there may still be a yield advantage to the shorter-season crops if heat and drought hit during flowering of the full season varieties.
There can be an advantage with rotations too, he said. If you plant early and have an early-maturing variety, you have the option to go back into wheat after harvest.
Mixing varieties and planting dates also works for corn, although there's not usually as much variability in corn planting dates as there is for some other crops, Fjell said.
"We tend to plant corn as soon as we can get into the field. But we could change some of the hybrids we plant, and pick for staggered maturity," he said. "For example, instead of using all 110- to 115-day-maturing hybrids if a farmer plants early, he might consider planting some of his acreage in 95- to 105-day-maturing hybrids. That in itself is a huge difference and should help in spreading out risk."