How many joules of energy reach the green plants?

The amount of energy that reaches green plants primarily comes from sunlight, with approximately 1,000 watts of solar energy hitting each square meter of Earth's surface on a clear day. However, only about 1-2% of this energy is captured by plants through photosynthesis, which translates to about 20-40 joules per square meter per second. Over a growing season, this can accumulate to several million joules of energy per square meter, depending on the location and environmental conditions.