Before corn tassels ... or wheat heads

Plants strive.  Leaves hog every once of sunlight, CO2, and drop of water they can.  Notice how erect they are.

The sugars from the sun, water, and CO2 exudate from the roots.

Then...it stops.  The annual plant puts its energy into producing seed to reproduce 

The leaves relax...allowing a larger solar corridor.  This is when we need what's next to gain steam.

This is why intercropping is vital for maximum productivity.  The soil needs plants in the juvenile and adolescence stage to feed the microbes and keep the soil from collapsing from starvation.

Intercropping requires an understanding of polymath... with some compromise built into the system.