Soybean, soy bean, or soya bean growth phases are classified according to two main growth phases, namely Vegetative (V) and Reproductive (R). These stages are determined by leaf, flower, pod and seed development. The V-phases are numbered according to how many fully-developed trifoliate leaves are present, and the R-phases point to different flowering, pod development, seed development, and plant maturation stages.
Knowing the current growth stage of your plant is important. Fertilisation, irrigation, disease, and pesticide application are determined by each growth stage. Growth stages can overlap, so when determining the growth stage of your crop, consider that the next growth stage can begin when 50% or more of the plant is in or beyond the previous stage.
Soya Bean Growth Stages
Vegetative (V) Stages
- VE – Emergence – Cotyledons (embryonic leaves) emerge from the soil surface.
- VC – Cotyledon – Unifoliolate leaves sufficiently unroll, so the leaf edges do not touch.
- V1 – First node – One set of unfolded trifoliolate leaves.
- V(n) – nth trifoliolate – V stages continue with the unfolding of trifoliolate leaves.
Reproductive (R) Stages
- R1 – Flowering begins – Plants have at least one flower.
- R2 – Full flowering – One open flower at one of the two uppermost nodes.
- R3 – Pods form – Pods are about 5mm in size at one of the four uppermost nodes with a fully developed leaf.
- R4 – Fully formed pods – Pods are about 2cm in size at one of the four uppermost nodes.
- R5 – Seeds form – Seed is 3mm long in the pod at one of the four uppermost nodes on the main stem.
- R6 – Full seed formation – Pod containing a green seed that fills the pod capacity at one of the four uppermost nodes on the main stem.
- R7 – Maturity begins – One normal pod on the main stem has reached its mature colour (grey, tan or brown)
- R8 – Plants reach full maturity – 95% of the pods have reached their full mature colour (grey, tan or brown).
Determinate and Indeterminate Cultivars
Determinate cultivars stop growing (V-stages) once they reach the reproduction phase (R-stages), while indeterminate cultivars will continue to grow (V-stages) while flowering (R-stages), resulting in a bigger plant. Most commercial soya bean cultivars are indeterminate, including the Y657 from Southern Seeds Hemisphere.
Want to try one of our soya bean cultivars in your next harvest?
Our Intacta® RR2 Pro soya bean seeds can be purchased in bulk at any of our agents. For more information on any of our soya bean cultivars, please contact our South African SHS branch at 081 490 9825 for more information.