April 24, 2012

Planters are rolling throughout the state and, given the size of today’s equipment, corn planting is rapidly progressing.

Based on UNL research, we would encourage you to consider planting your soybeans as soon as possible—preferably before the end of April for the southern two-thirds of Nebraska and or the first week of May for the northern third of Nebraska. While evening temperatures have been low, consider the percent risk of frost for emerged plants not planted seeds. The above recommendation considers a 10% risk of frost 7-10 days after planting, the time when soybeans would most likely emerge.

Why plant early? Five years of UNL small plot and on-farm research has proven that early planted soybeans yield more than late planted beans—regardless of whether the spring has been cold and wet or warm and dry. Soybeans are a photoperiod-sensitive crop so the goal is to allow the plant to use the sun’s energy to accumulate as many nodes as possible as day length decreases after June 21. Nodes are important because that’s where pods, seeds, and ultimately yield are produced.

Table 1 shows how three years of on-farm research have resulted in an average of 3 bu/ac yield increase (with a range of 1-10 bu/ac depending on the year and the planting date range of early versus later planting). With today’s soybean prices, a 3 bu/ac yield increase adds up (see Table 2). We do recommend a fungicide/insecticide seed treatment to reduce the risk of damping off diseases and bean leaf beetles which tend to feed on early-planted soybeans. 

Further Information

Several previous CropWatch articles explain soybean planting date in more detail. Please see these for more information:

• For Increased Yields Plant Soybeans in Next Two Weeks
• Three Reasons Why Soybean Planting Date Matters
• Farm Research Shows Benefits of Planting Soybeans Early
• Risks and Caveats of Early Planting Soybeans

Jenny Rees, UNL Extension Educator
Jim Specht, UNL Professor of Agronomy and Horticulture