Mississippi had little relief from rainfall the first half of April. I hope that by the time you read this, these fronts will have begun to spread out.
Many questions have surfaced regarding various aspects of soybean production. I hope the following points will help answer some questions.
Planting dates: Regardless of what you think, is not too late to plant Group IVs. The last couple of springs have really spoiled us, and we would like to have more planting completed by now.
Group IVs planted in what most consider a cotton window (April 20 to May 10) will get taller than when planted earlier. For those planting on wide rows, this is important. However, on 20-inch rows or less, it should not be a problem. Group IVs will grow off better on well-drained, high-fertility soils.
We grow very few varieties today that get as big, tall, and large as the ones we grew 15 years ago. If you are growing early-maturing soybean varieties in wide rows, growth may be a concern. If beans fail to grow off as much as you want, consider some alternative herbicide options (layby rig), even Roundup Ready soybeans.
Maturity groups: When comparing maturity groups, little difference exists between conventional IVs and Roundup Ready IVs. In the case of Group Vs, however, differences still exist. The way to overcome this potential yield difference is to be very selective when choosing varieties.
Good varieties are available, but do not sacrifice yield just to use a particular herbicide system. Yield is the ultimate goal.
Dryland vs. irrigated: The early planting concept is valid. You owe it to yourself to give it a shot. Group IVs planted after May 10 will mature like a Group V, most likely an early Group V. I am constantly asked how long I would plant Group IVs. I would never alter my original plans.
If you were to swap varieties, you most likely will replace it with a Group V. By planting later than early May, that is exactly what you now have, but it is an indeterminate Group V.
Attempt to plant non-irrigated acreage first, utilizing your earliest-maturing varieties. For those of you wanting to use some Group IIIs, use caution. Planting extremely early will affect plant height, particularly where drainage is not adequate.
Some people believe that we should plant Group IVs and Group Vs first and plant Group IIIs later. This will allow for more growth, but you will give up the earliness advantage most are interested in.
If you reverse the order of planting, you will have some early-planted Group IVs and Group IIIs ready for harvest at the same time. Keep this in mind as you begin planting. We do not have to get in as big a hurry planting irrigated acreage as many people believe. Sure, there are advantages, but a goal of completing planting by mid-May should allow us to achieve above average yields most years.
Seed treatments: I continue to see growers not using proper seed treatments. Use of the proper seed treatment can avoid costly replants. Center your seed treatment program around an Apron-type material for control of pythium (Apron, Apron XL, Allegiance, etc.). You can broaden the spectrum by adding materials active against rhizoctonia (Vitamax, Maxim, etc.).
The need to replant can be eliminated by using the proper seed treatment. Seed treatments are a form of insurance. Yield increases are not always observed in side-by-side comparisons, but if you have to replant, even if it costs nothing, the difference in planting dates translates into a significant yield difference.
Since 1992, we have had 212 fields in our statewide SMART program. This encompasses numerous years, planting dates, and varying soil types. We have had to replant only twice. Once when a field went under water due to the Mississippi River, and another time when a grower did not use what we suggested (instead of an Apron type material, he used Vitavax alone).
I do not sell seed treatments, but using a seed treatment is one of the most cost-effective options we can have. This is a no brainer.
Seeding rates: We have a tremendous amount of flexibility in the area of seeding rates. Personally, I am a fan of lower plant populations due to the potential savings. If you are in 20-inch rows, drop five seed per foot of row; 38-inch rows, drop seven; 15-inch rows, four; and 7.5-inch rows, two per foot of row. These populations are adequate. Do not overplant. Think in terms of seed per foot of row, not pounds per acre.
The biggest concern we have on thin stands are big skips. You can tolerate a thinner stand with Roundup Ready soybeans due to the broad spectrum of Roundup. Irrigation is another excellent option that compensates for lower populations.
Over the last few years, I have observed several fields where stands have ranged from 1.8 to 2.0 plants per foot of row in 30-inch rows. These fields were irrigated and still cut 60 plus bushels per acre.
Seed size is only important in the potential number of acres per bag. Set planters based on seed per foot of row not pounds per acre.
Inoculation: If you are planting soybeans for the first time in three to four years, be sure to inoculate the seed. Several producers around Mississippi who rotate crops inoculate every year and really like the early growth they observe.
Farmers planting beans on cotton ground for the first time should not overlook this important input. This is not expensive, but is felt by many to be quite time-consuming at planting. It is time-consuming, but it can be much more costly if you find out 60 days into the crop you are deficient in nitrogen.
Field activity is about to move exceedingly fast. If we can help in anyway, please do not hesitate to give us a call. Information is abundant. All of us working in the area of crop production want to do all we can to help you succeed each and every year. However, it is important that you do your part and seek out the most up-to-date unbiased information available.
Alan Blaine is the Mississippi Extension soybean specialist.