By Blake Jackson
Planting time is a make-or-break moment for Missouri soybean farmers, according to Andre Reis, a University of Missouri Extension specialist. While weather later in the season can impact final yields, the groundwork for a bountiful harvest is laid during planting.
This critical period hinges on three key factors: planting date, soybean variety selection, and plant population. Any stress encountered throughout the growing season can only diminish or maintain the yield potential established at planting.
Variety selection is aided by field trial results from the Missouri Variety Testing program (MUVT) and seed companies. Analyzing top-yielding varieties reveals a clear trend: later planting dates translate to lower yields.
This penalty is most severe in the southeast, with yield losses exceeding 0.4 bushels per acre per day delayed from March to June. While the decrease in yield potential over planting time has been documented before, there's significant variation across Missouri's regions.
The ideal maturity group (MG) for soybeans can also be a puzzle. While there's no simple formula to connect MG with planting date for peak yields, the University of Missouri is launching multi-environmental trials in 2024 to address this challenge. These trials will explore the optimal combination of MG, planting date, and plant population for various regions within the state.
In the meantime, a machine learning model can provide guidance based on planting date and weather conditions. For wet years, early April plantings should prioritize early MG varieties in most counties. As planting progresses into May and June, a switch to intermediate MGs is recommended. It's important to remember that MG classifications are relative to the region.
Dry years call for a different approach. The model suggests intermediate MGs for the northern region and early MGs elsewhere during April plantings. By May, most areas should transition to intermediate MGs, with late MGs preferred for June plantings, particularly in the Bootheel and some northern regions.
This shift in MG selection between wet and dry years reflects a strategy to avoid drought by adjusting seed filling to occur before the hot and dry period in late July and August.
While there are many challenges in establishing a high-yielding soybean crop, planting early (weather permitting) and selecting the optimal MG for the region are crucial first steps.
The complex interplay between planting date, maturity group, and plant population is an ongoing area of research for the University of Missouri Soybean Farming System Program.
Photo Credit: istock-urpspoteko
Categories: Missouri, Crops, Soybeans