April 24, 2012

Research: Planting Soybeans Early Results in Increased Yield


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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:

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

 

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

Row
Spacing
(inches)

Yield (bu/ac)
 2008SCAL EarlyApr. 29 3 IrrigatedProducers 286 30 67.2
 2008SCAL LateMay 15 3 IrrigatedProducers 286 30 65.8
 2008Seward Co. EarlyApr. 30 3 IrrigatedNC+ 2895 30 68.4

2008

Seward Co. LateMay 19 3 IrrigatedNC+ 2895 30 66.2
 2008York Co. EarlyApr. 23 8 IrrigatedProducers 286 30 66.9
 2008York Co. LateMay 14 8 IrrigatedProducers 286 30 63.5
 2008Fillmore Co. EarlyApr. 30 7 IrrigatedPioneer 93M11 30 81.0
 2008Fillmore Co. LateMay 19 7 IrrigatedPioneer 93M11 30 77.5
  2009SCAL EarlyApr. 27 4 RainfedPioneer 93M11 30 37.6+
  2009SCAL LateMay 18 4 RainfedPioneer 93M11 30 37.2
  2009Saunders Co. EarlyMay 3 6 RainfedNC+  A63RR 15 66.6
  2009Saunders Co. LateMay 21 6 RainfedNC+  A63RR 15 65.1
  2009SCAL EarlyApr. 27 4 IrrigatedPioneer 93M11 30 70.2
  2009SCAL LateMay 18 4 IrrigatedPioneer 93M11 30 68.1
  2009Fillmore Co. EarlyApr. 24 4 IrrigatedPioneer 93M11 30 69.5
  2009Fillmore Co. LateMay 15 4 IrrigatedPioneer 93M11 30 68.4
  2009Seward Co. EarlyApr. 24 4 IrrigatedNC+ 2A63 30 73.2
  2009Seward Co. LateMay 20 4 IrrigatedNC+ 2A63 30 71.3
  2009York Co. EarlyApr. 30 3 IrrigatedNK 28B4 30 59.1
  2009York Co. LateMay 15 3 IrrigatedNK 28B4 30 58.6
 2010Saunders Co. EarlyApr. 18 6 RainfedChannel 2751 15 75.7
  2010Saunders Co. LateMay 18 6 RainfedChannel 2751 15 71.2
  2010Seward Co. EarlyApr. 19 6 IrrigatedChannel 3051RR 30 72.0
  2010Seward Co. LateMay 24 6 IrrigatedChannel 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