At which growth stage do soybeans reach full maturity?

Soybeans reach full maturity at the R8 growth stage. At this point, approximately 95% of the pods have reached their full mature color, which indicates that the plants have completed their reproductive cycle and are ready for harvest. This stage is crucial as it signifies that the beans inside the pods have fully developed and their moisture levels have decreased enough for proper handling during harvest.

Understanding why R8 is the correct answer entails recognizing that the previous stages focus on earlier signs of maturity, such as pod development and the color changes of the pods. For instance, R5 and R6 represent stages where a smaller percentage of pods (50% and 75%, respectively) have matured, while R7 covers around 90% of pods. However, it is at R8 that we see the benchmark of 95% maturity, which denotes readiness for harvest and optimal conditions for soybean quality and yield. Thus, R8 is specifically designated as the maturity stage in soybean growth.