> [Citation needed]
pvaldes, 2020
Some facts are so well stablished in human knowledge that there is not need to cite it. For example: "Some crops are more productive than other. Point".
We, humans know it since 10.000 years ago. Anybody can see it with their eyes. Not need to repeat what Aristotle would say about it.
Primary and secondary production, is a big fat chapter in any Ecology handbook. Any Plant physiology handbook will explain the differences between CAM and C4 plants
If nobody is trying to produce a natural sized cow sculpture made of vanille beans, there must be a reason.