STONEVILLE, Miss. - With so many Mid-South soybean producers jumping into the early planting pool, some may be wondering if the plunge comes at too steep a cost. At this early stage, however, growers needn’t worry that what felt like a swan dive was actually a belly-flop, according to soybean experts.
As an example of the seeding pace this spring, Mississippi reports the state’s soybean acreage at 21 percent planted on April 4. “That’s unheard of. A quarter of our acreage was planted by last Sunday! That’s amazing,” says Larry Heatherly, senior research agronomist with the USDA-ARS Soybean Production Research Unit at Stoneville.
“I’ve been here working for 29 years, working with early planted soybeans for about 18 of those, and am for one thing only: whatever makes farmers money. That’s all I’m after. Farmers should know risks inherent with any system. But anyone who’s planted early and is now feeling regret shouldn’t worry.”
Alan Blaine, Extension soybean specialist for Mississippi, has taken calls from producers wondering if they’ve made a mistake by planting so early. He says that strictly from a physiology standpoint, early planting is a good thing. However, it’s undeniable that, with so many early beans going in, other issues have surfaced.
“Harvest capacity is an issue, no doubt,” says Blaine. “Our speed of planting has compressed harvest into a very narrow time frame. There are a lot of folks that will make that August premium and some that won’t. I’m addressing this strictly from a physiology and yield standpoint.”
He says planting early has helped improve Mississippi soybean yields.
“For over 20 years, the state average soybean yield in Mississippi was 21 bushels,” he notes. “Over the last decade, we’ve seen that average increase by 10 bushels per acre. When you consider that long-term yield average, many producers – particularly dryland – have nothing to lose by trying something different like early planting. The early planting system is the best thing to come along prior to Roundup Ready.”
Blaine says there are four things that have happened over the last decade or so that have benefited the Delta soybean crop: 1) Higher yielding varieties, 2) Use of earlier maturity groups, 3) Earlier planting dates, and 4) Roundup Ready technology.
Based on his early-planting research, Heatherly recently broke Blaine’s points down further. Among his comments:
On cold soil and frost:
“We have a top-notch weather station here in Stoneville. The station has released a 30-year average of weather variables that runs from 1971 through 2000.
Here in Mississippi, the 50 percent last frost date (frost temperature defined as 36 degrees) is March 28. That means that, on average, the last frost occurred on March 28. If we look at the 1999 through 2004 weather data, the average last frost date is March 19. Regarding frost, Mississippi producers should know we’re past the point of concern.
“If we plant our soybeans very early, we aren’t concerned about soil temperatures provided we treat seed with a proper fungicide. Pythium, the main concern in cold soils, is what we must protect against.
“I’ve seen soybeans that have been through a frost. Visibly, it didn’t affect the stand at all. How much a plant is affected probably depends on how much of the growing tip is exposed. The growing tip comes out several days after the crook emerges. That’s the part of the plant susceptible to cold injury, if it’s affected at all.
“I’m of the firm belief that we don’t have to be concerned with frost. We probably have to be concerned about freezes, though. However, the last 50 percent last freeze date at Stoneville is March 10.
“Granted, in cool temperatures, soybeans – or any other plant – won’t grow as fast. But we want the plant already up and ready to move when the sun warms the soil.”
On replanting an early crop:
“I’ve been doing this for many years and have yet, in research work, to replant an early planting. In fact, I’ve had more stand problems when planting in May and June. That’s because, in late plantings, we run out of moisture.
“Conversely, when planting very early, we’re planting into a better moisture environment and spring rains will help keep it that way. We don’t have to worry about dry soils affecting emergence. That means - at least in my work - there’s less risk in getting a stand early than one late.”
On seeding rates and weeds:
“There’s also a perception that when planting early seeding rates should be bumped up. I have no data to verify that in either direction. However, I’ve never changed a seeding rate and have always gotten acceptable stands of 100,000 to 150,000 plants per acre. Row spacing doesn’t matter - I care about plants per acre.
“I just don’t have a fear of stand problems due to early planting. I’ve seen soybeans take 17 days to emerge. But when treated properly, once temperatures pick up and soils dry a bit, the stand comes up perfectly.
“Planting soybeans so early works to the crop’s benefit in another way. Oftentimes, we don’t see weed emergence for 4 to 6 weeks. Weeds require very warm temperatures to emerge - especially summer annuals like teaweed. That means we’ve got a soybean plant growing in a weed-free environment.”
On the reproductive phase:
“July is our hottest month. If I have a plant starting bloom in May, and filling seed in June and early July, that’s a better situation than if the pods were filling in late July and August. Why? Because, in Mississippi, June temps aren’t as hot, and we’ll still have soil moisture to fill seeds. In June, the average maximum temp is 90. In July, it’s 91.5. In August, it’s 90.5.
“It’s a known fact that soybeans planted early will be shorter. But it’s also true that height has nothing to do with yield. In my research, I’ve seen many years where 24-inch tall soybeans in narrow rows yielded as high as anything else. If it’s in narrow rows, we don’t need a big plant to make yield. We need a plant doing the right thing at the right time.
“Now, the fellows who put beans on wide rows could be facing some problems. But they knew the risks. If their crop doesn’t canopy and it’s a Roundup Ready, they can go in with a late application of glyphosate. Or, some producers may prefer to cultivate.”
“Early planting, in my opinion, means less risk for producers than delayed plantings. I don’t want our farmers to worry too much. True - because there isn’t a whole lot of research data concerning planting in mid-March - there are questions. What we do have is a lot of experience with this. Anyone who planted in mid-March or later is set up to utilize weather conditions that should allow high yields.”