These two photos of raspberry come from the same variety, planted the same time, about 20 miles apart in similar soils, but with completely different nutrition management.
It is interesting to observe how plants express themselves differently in different environments. When we learn what to look for, it is possible to identify some of the subtle indicators of plant health and yield potential.
When you compare these two photos, note the differences in the definition of the leaf edges, how the leaf shoulder is shaped where it is attached to the petiole, leaf flatness, and length to width ratio.
It is worth noting that the nitrogen content in these leaves is practically identical, yet one has much higher chlorophyll concentrations.
What else can you observe that I missed pointing out?