All winter long growers have been bombarded with articles, meetings and retailers preaching the benefits of early soybean planting. For some growers this is their 2nd, 3rd or even 4th year of harvesting the benefits of early soybean planting, but for many growers this may be their first experience. To be successful and achieve the extra 8 – 10 bushels that have been advertised there a few things to consider.
Planting soybeans earlier means dealing with cooler and possibly wetter soil conditions. This is a prime environment for fungal pathogens. A good seed treatment is recommended for a couple of reasons. One, obviously, is to protect the seedling against fungal pathogens like phytophthora, which thrive in cool, wet soils. The chances of seeing SDS in soybeans increases with early planting as well. ILeVO® seed treatment has shown very good control in fields with a history of SDS. The “standard” seed treatment also includes an insecticide. This will offer up a few weeks of protection for a seedling. As one of the first emerging soybean fields, it will be a magnet for bean leaf beetles. With a “standard” seed treatment offering, most companies offer a free replant policy. It’s a nice safety net if there’s a need to replant before insurance date coverage.
A tillage pass across wet soil can cause a horizontal density layer that will haunt you all season long. This density layer will not allow root penetration to the soil moisture and nutrients below it. The planter can also cause damage when planting into wet soils as the seed furrow will never fully close. If drought or dry conditions persist, the seed trench will remain open, allowing valuable moisture to be lost. Soybeans can be more forgiving in these situations, but its best to not test just how forgiving.
Soil temperatures need to be stable for roughly 48 hours after planting. The initial imbibition phase is important to the seed. Initial intake of water that’s too cool can do permanent damage to the seedling. Soybeans can take cooler soil temperatures than corn. 48 degrees isn’t out of the question and more testing is being done to see if temperatures can be lower than that. Planting depth may also need to be adjusted if inclement weather is forecasted after planting. A depth of 1.5 – 2” will provide a buffer against frosts or freezing temperatures post planting. It will also delay emergence in situations of extremely early planting.
Pre-emergence chemical application can be a challenge with early soybean planting. Some retailers are not well equipped to cover large acres of both corn and soybeans at the same time. A conversation with your retailer in advance of early planting is recommended. PPO chemistries provide great control, but also have crop safety concerns in cool emergence conditions. Growers may have to do a post-applied residual option. This can be combined with an early post application to kill any emerged weeds and extend the timeline of residual control.
While planting the last week of April may not seem “early” to some, it has shown extremely consistent and positive yield results. Planting earlier than that is truly a risk versus reward decision. The last few years have shown some impressive yield data from late March planted soybeans, but also comes with much more risk than that late April planting date. I think it has been established at this point that for some growers, soybeans are not the crop we thought they were a mere 5 years ago. There’s a good chance that 5 years from now, half or more of a grower’s soybean crop will be planted before the first kernel of corn sees the dirt.