Soybean Growth Staging Guide

Click box to view image of each growth stage
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Avg. Days After Planting Growth Stage Description
10
V-E Emergence
Cotyledons have been pulled through the soil
20
V-C Unifoliate
First unrolled unifoliate leaf (single leaflets)
30
V-1 Trifoliate
First unrolled trifoliate leaf (three leaflets)
35
V-2 to V-4 Trifoliate
Second unrolled trifoliate, third unrolled trifoliate leaf, fourth etc.
45
R-1 Early Flower
Plants have at least one open flower at any node (point where leaf attaches to the stem)
50
R-2 Full Flower
Plants have an open flower at one of the two uppermost nodes on the main stem
60
R-3 Early Pod
Pods are 1/4-inch long at one of the four uppermost nodes on the main stem
70
R-4 Full Pod
Pods are 3/4-inch long at one of the four uppermost nodes on the main stem
80
R-5 Early Seed
Seeds are 1/8-inch long at one of the four uppermost nodes on the main stem
90
R-6 Full Seed
Pods contain green seeds that fill the pod to capacity at one of the four uppermost nodes on the main stem
110
R-7 Early Maturity
Majority of pods are yellow and at least one pod on the main stem has reached its mature colour (tan/brown)
120
R-8 Full Maturity
95% of pods have reached their mature colour (tan)
130
Harvest
Harvest can begin when seed moisture is approx. 14%



Plant Population

High: (>160,000 plants/ac)

This is generally beyond the optimum plant stand for soybeans - disease presure may be increased.


Good: (120-160,000 plants/ac)

Plant stands between 120,000 and 160,000 plants/ac are estimated to produce 95 to 100% of optimum yield.

Adequate: (80-120,000 plants/ac)

Risk of yield loss due to low plant population - plant stands between 80,000 and 120,000 plants/ac are estimated to produce 84 to 95% of optimum yield.

Low: (< 80,000 plants/ac)

High risk of yield loss due to low plant population - attention to weed control will be important and low pod height may be a problem at harvest.

Plant population and yield information is based on final research results from Mohr et al. 2014. The effect of actual plant stand on relative yield of soybean was determined based on13 site years of data in Manitoba from 2011-2013.

Average number of days from planting observed in Manitoba. This can fluctuate by 5-10 days depending on region and variety.