Historically, soybean planting dates have been delayed relative to corn and were considered non-critical in regards to yield potential. However, research has shown that early planting can be critical for increasing soybean yield potential.
By planting early, canopy photosynthesis can be increased throughout the season. Increased photosynthesis comes from a large soybean canopy to maximize the solar radiation captured during the June and July time period. This can lead to increasing the number of plant nodes, lengthening the reproductive period due to earlier flowering, and increasing the crop growth rate during pod set, which can lead to a greater seed filling rate. The early canopy development can also help: 1) in the conservation of soil moisture, which is critical during reproductive periods, 2) reduce weed competition early in the season, and 3) may help prevent later emerging weeds from becoming a problem.
When planting early, it is important to wait until good soil and seedbed conditions exist. Planting when soil is too wet can result in compaction, poor seed placement, and poor stand establishment. Excessive tillage or a heavy rain soon after planting can result in soil crusting, which may lead to a reduced stand. Soybean seed planted into wet soils will likely negate any potential yield advantage from planting early.
Data from several universities suggests planting soybean seed early (in late April or early May) can help maximize yield potential. Available data should be examined in order to make an informed decision on planting date. While there are risks, the potential yield benefits for early planting are compelling and tools are available to help mitigate most risks associated with early planting.
Along with benefits, planting early can have a negative impact on soybean yield potential. Consider the following recommended management practices to help limit some risks associated with early soybean planting:
Establishing good stands may require:
1Soybean planting recommendations: date, seeding rate, relative maturity. 2013. The Ohio State University. Corn + soybean digest. http://cornandsoybeandigest.com/soybeans/soybean-planting-recommendations-date-seeding-rate-relative-maturity.
2Staton, M. 2011. Planting soybeans early offers many benefits. Michigan State University Extension. http://msue.anr.msu.edu/news planting_soybeans_early_offers_many_benefits.
3Pedersen, P. Soybean planting date. Iowa State University Extension. http://extension.agron.iastate.edu.
4Severson, R. 2013. Soybean planting date and delayed planting. University of Minnesota Extension.http://www.extension.umn.edu/agriculture/soybean/planting/soybean-planting-date-and-delayed-planting/.
5Berglund, D.R. and Helms, T.C. 2003. Soybean production. A-250 (Revised). North Dakota State University. https://www.ag.ndsu.edu 6 Roozeboom, K. 2012. Soybean planting dates: Is earlier a good Idea? AG Professional. http://www.agprofessional.com
Web sources verified 04/13/16. 140405061002