UNIVERSITY OF MISSOURI EXTENSION
 

Last Soybean Irrigation

Step 1

Pull up typical plant.

Step 2

Tear off all leaves.

Step 3

Count down from top 4 nodes; tear plant here and discard bottom part.

Step 4

Find the pod that is most fully developed; key off of that pod.

Step 5

Use stage of that pod and Table 1 to decide on whether to continue irrigating.

Table 1. What Maturity Stage to be at for the Last Full Irrigation
 Without HardpanWith Hardpan Above 10 inches
Soil TypeSprinklerFloodSprinklerFlood
Coarse sandR6 +++R6 +R7R6 ++
Fine sand, Loamy sand, Clay, Clay loamR6 +R5 ++R6 ++R6 +
Sandy loam, Fine sandy loam, Very fine sandy loamR6 +R5 ++R6 ++R6 +
Silty clay, Silty clay loam, silt loamR5 ++R5 +R6 ++R6
Table 2. Later Soybean Stages
StageOn the top 4 nodes:
R5One pod has beans that can be felt.
R5+1/3 of pods have beans that can be felt.
R5++2/3 of pods have beans that can be felt.
R6One pod has touching beans.
R6+1/3 of pods have touching beans.
R6++2/3 of pods have touching beans.
R6+++Nearly all pods have touching beans.
R7One pod has final mature color.