Considerations for Early Planting of Soybeans

Early-season soybean management decisions can have large effects on how products respond to the environment and the overall yield potential. As soybean management plans are made, some important early-season factors should be considered.

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Figure 1

Figure 1. Comparison of the development of soybeans planted at four dates. Photo courtesy of Dr. James Specht, University of Nebraska-Lincoln. Source: Bastidas, A.M. et al. 2008. Soybean sowing date: the vegetative, reproductive, and agronomic impacts. Crop Science. vol 48: 727-740.

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Benefits of early planting.1 Earlier planting dates typically have the potential to produce higher soybean yields due to the following factors:

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  • With early planting, soybean plants can produce larger canopies earlier in the season (Figure 1), which can intercept more light leading to greater overall photosynthesis and conservation of soil moisture, which is critical during reproductive periods.
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  • Earlier planting can lead to a longer growing season, which can result in an increase in the number of nodes on the main stem and potentially more pods per plant.
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  • Earlier planting can lengthen the reproductive period due to earlier flowering and increase the crop growth rate during pod set, which can lead to a greater seed filling rate.
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Planting dates. The University of Nebraska recommends to plant your soybeans as close to May 1st as possible. Approximately 1/2 bu/acre of yield potential can be lost for every day after May 1 that planting occurs.2 Planting into a suitable seedbed should be the most important consideration for a successful soybean crop. Soils that are too wet and cool for planting may negate any yield advantage from planting early due to the increased probability of soil compaction and seedling pests.

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Weed control. An herbicide program that controls weeds early and through canopy is imperative to help protect yield. An early spring burndown is important for a clean start. Weeds emerging prior to or at planting are the most competitive with the crop. A significant portion of yield is at risk if early emerging weeds are allowed to compete with soybeans during the first several weeks after planting.3

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A comprehensive weed control program should include:

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  • The use of multiple, overlapping residual herbicides at full labeled rates along with post- emergent herbicides to help maintain a clean field.
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  • Herbicides need to be selected to match the weed spectrum in the field. Rotating herbicides with different sites of action is important to help prevent herbicide resistance.
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  • Roundup Ready PLUS® Crop Management Solutions, which can be found at www.roundupreadyPLUS.com, can be the foundation for a strong weed control solution.
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Seed treatments. Early-season insects and diseases can have an adverse effect on stand establishment and yield potential. Cool, wet soils common with early planting dates can prolong emergence, making the seeds/seedlings more susceptible to diseases and insect pests. Fungicide seed treatments can provide protection from early-season diseases such as Phytophthora, Pythium, Rhizoctonia, and Fusarium. Insecticide seed treatments can help provide protection against early-season insect pests, such as the first generation of bean leaf beetle.