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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:

Table 1. Yields from Nebraska on-farm research of early and late planted soybean (2008-2010)

Year  Producer Date Repetitions Rainfed/
Irrigated
Variety

Row
Spacing
(inches)

Yield (bu/ac)
 2008 SCAL Early Apr. 29  3  Irrigated Producers 286  30  67.2
 2008 SCAL Late May 15  3  Irrigated Producers 286  30  65.8
 2008 Seward Co. Early Apr. 30  3  Irrigated NC+ 2895  30  68.4

2008

Seward Co. Late May 19  3  Irrigated NC+ 2895  30  66.2
 2008 York Co. Early Apr. 23  8  Irrigated Producers 286  30  66.9
 2008 York Co. Late May 14  8  Irrigated Producers 286  30  63.5
 2008 Fillmore Co. Early Apr. 30  7  Irrigated Pioneer 93M11  30  81.0
 2008 Fillmore Co. Late May 19  7  Irrigated Pioneer 93M11  30  77.5
  2009 SCAL Early Apr. 27  4  Rainfed Pioneer 93M11  30  37.6+
  2009 SCAL Late May 18  4  Rainfed Pioneer 93M11  30  37.2
  2009 Saunders Co. Early May 3  6  Rainfed NC+  A63RR  15  66.6
  2009 Saunders Co. Late May 21  6  Rainfed NC+  A63RR  15  65.1
  2009 SCAL Early Apr. 27  4  Irrigated Pioneer 93M11  30  70.2
  2009 SCAL Late May 18  4  Irrigated Pioneer 93M11  30  68.1
  2009 Fillmore Co. Early Apr. 24  4  Irrigated Pioneer 93M11  30  69.5
  2009 Fillmore Co. Late May 15  4  Irrigated Pioneer 93M11  30  68.4
  2009 Seward Co. Early Apr. 24  4  Irrigated NC+ 2A63  30  73.2
  2009 Seward Co. Late May 20  4  Irrigated NC+ 2A63  30  71.3
  2009 York Co. Early Apr. 30  3  Irrigated NK 28B4  30  59.1
  2009 York Co. Late May 15  3  Irrigated NK 28B4  30  58.6
 2010 Saunders Co. Early Apr. 18  6  Rainfed Channel 2751  15  75.7
  2010 Saunders Co. Late May 18  6  Rainfed Channel 2751  15  71.2
  2010 Seward Co. Early Apr. 19  6  Irrigated Channel 3051RR  30  72.0
  2010 Seward Co. Late May 24  6  Irrigated Channel 3051RR  30  62.3
  Average Early            70.0*
 

Average Late

         

67.1

*Statistically significant at 95 percent level.
+ Yield from the rainfed trial at the UNL South Central Agricultural Laboratory (SCAL) was not included in the combined statistical­ ­analysis, but yield from the Saunders County rainfed trial was compared with irrigated yields from other locations.

Table 2. Economic advantage from a 3 bu/ac yield increase due to early soybean planting date

Price of Soybeans

$6.00

$7.00

$8.00
$8.00
$10.00
$11.00
$12.00
$13.00
$14.00

Economic Advantage

$18.00

$21.00

$24.00
$27.00
$30.00
$33.00
$36.00
$39.00
$42.00

Source: University of Nebraska-Lincoln