I spotted this graph, describing a study from India, on CO2 and plant growth. It brought back my Junior College lectures on soil fertility. It isn’t a new topic for research – but it is one that considers one of the concerns about atmospheric CO2.
The lecture worked from fertilizers – and the big three are Carbon, Hydrogen and Oxygen. In general, the carbon comes from organic material in the soil. Here in Trego, I’m raising grass on relatively new soil – maybe 12,000 years of development since the glaciers left. It doesn’t have a lot of organic carbon . . . a nice way of saying it isn’t particularly fertile. The hydrogen and oxygen come from rainfall and irrigation. The nitrogen either comes from soil bacteria or commercial fertilizer.
We look at nitrogen, phosphorus and potassium as macro-nutrients – but compared to carbon, oxygen, hydrogen and nitrogen, they too are micronutrients. We call them macronutrients – they’re the ones on the fertilizer sack. But carbon and water are the heavy lifters in plant growth.
As the graph shows, much of our CO2 fertilization has been a byproduct of industry – CO2 emissions. That increased CO2 has an influence on crop yields. Like many things, atmospheric CO2 can be a blessing or a curse. Input and output appear to have an imperfect positive correlation.
Another study includes this NASA illustration:
I would expect more nutrients and a little longer growing season to result in more plant growth. On the other hand, I suspect those purple fringe areas may indicate reduced precipitation, and its subsequent lower production.
Meanwhile, in sciencealert there’s a piece taken from the Journal of Political Economy supporting a hypothesis that I also first taught in the mid-eighties. The journal abstract is:
The conventional theory about the origin of the state is that the adoption of farming increased land productivity, which led to the production of food surplus. This surplus was a prerequisite for the emergence of tax-levying elites and, eventually, states. We challenge this theory and propose that hierarchy arose as a result of the shift to dependence on appropriable cereal grains. Our empirical investigation, utilizing multiple data sets spanning several millennia, demonstrates a causal effect of the cultivation of cereals on hierarchy, without finding a similar effect for land productivity. We further support our claims with several case studies.”
My lecture from nearly 40 years ago was that cereal grains – wheat, barley, rye, rice, corn – were easily stored, nutrient rich, and made government possible . . . if you consider the first governments to be roughly the equivalent of neighborhood gangs. “Nice little granary and family you have here. Be a shame if something were to happen to it.” As Max Weber reminds us, when you get to the bottom line, government is a monopoly on the legitimate use of force.
If someone “taxes” your crop and you can’t prevent it, that someone is well on his way to becoming a government. I can make the argument that the next stage of government grew from irrigation canals and ditch riders. The guy who controls the H and O that your crops need has power. If his power is legitimized, he’s a government man – only different from the FBI or IRS in degree.
“Even when some parts of the world adopted farming and began producing a surplus of food, it did not necessarily lead to complex hierarchies or tax-levied states.
Only when humans began farming food that could be stored, divvied up, traded, and taxed, did social structures begin to take shape.
That’s probably why cereal grains like wheat, barley, and rice – rather than taro, yams, or potatoes – are at the root of virtually all classical civilizations. If the land was capable of cultivating grains, evidence shows it was much more likely to host complex societal structures.”
I don’t believe that the article coming out 35 years after I mentioned it in lectures proves that I was brilliant and ahead of my time. I suspect that it’s a new topic now because we have a generation of economists who grew up urban – without the on-farm experience that makes some of these things intuitively obvious.