MISSISSIPPI STATE, Miss. -- At mid-May, the Mississippi soybean crop was close to 90 percent planted. Progress has been well above average, but it all hinged on cooperative weather. Many areas west of us experienced weather extremes that hampered planting progress, but it is this type of weather that makes you realize the window of opportunity for early planting can be quite narrow.
We capitalized on earliness this year, but it required being prepared. If fields are dry enough in March/April to hold up a tractor, you have to take advantage of the opportunity. Any normal rain this time of year can take you out of the field for a week to 10 days, especially on clay soils.
Our approach to early planting needs to remain the same, just plant. I do not look at soil temperatures, but I do pay attention to drainage. It is very much like cutting hay, you have to start sometime, and the window can be very narrow early.
Several fields started blooming as early as the first week of May. These earliest blooms were on plantings that occurred mid- to late-March. Although this may be considered early, it is not a major cause for alarm. Larry Heatherly, USDA-ARS senior research agronomist at Stoneville, Miss., and others over the last few years have documented plants adding 40 to 70 percent growth after bloom. Plants that begin blooming at 8 inches are capable of achieving a final plant height of 20 to 30 inches — more than sufficient in narrow row plantings.
Determinate varieties are more of a concern, but we have experienced no height problems on plantings from late March to early April in over 15 years of testing.
In most years, plantings in late March to early April will not emerge until mid-April. That is not too early for Group 5s. Narrowing your row configuration can compensate for reduced height. If you feel that this goes totally against what you thought to be true, you may be correct. We did what we used to do (May and June plantings) because it was the best information we had at that time. Research has opened some new doors.
Another factor that we have not paid enough attention to is flat plantings. Soybeans planted on beds this year have grown off well. This is not as much due to drainage this year but temperatures. Beds warm faster and promote excellent early-season growth. If you told me I could utilize one input in soybean production, I would request a row every time. It is difficult to use narrow rows on beds, but given the advantage of beds, I expect to see an increase in wide beds and various other configurations. It is not essential for all acreage, but it can minimize many problems.
In recent years many have learned that it does not require a large plant to produce high yields. To achieve more height, a number of growers are planting Group 5s first, followed by Group 4s. This goes against spreading maturity, but they are achieving more plant growth.
Sometimes height is reduced by cool, wet conditions which causes stunting. Even if this occurs, a taller growing Group 5 has helped minimize the problem. However, we still need to plant our Group 4s first and finish with our full-season varieties.
In 1992, I saw several hundred acres of Hutcheson (Group 5) — planted on 30-inch rows and furrow irrigated — cut over 70 bushels per acre. Once they dried down, they averaged 14 inches in height. A tremendous yield from fairly short plants.
In the mid 1990s, Floyd Hancock and others conducted a planting date/row spacing study. Hutcheson was one of the varieties used in this test. If there is one universal complaint, it was that it was too short. In those tests Hutcheson yielded the highest when planted early (late March).
If you do a good job matching variety to row spacing, you will lower yields by planting early. If you can irrigate, however, you can plant anytime in an April to early May window and still achieve high yields.
Alan Blaine is the Mississippi Extension soybean specialist. e-mail: [email protected].