Recently there has understandably been a lot of focus on the extremely high prices of agricultural products. The front Corn futures contract hit an all-time month-end high back in April, at over $8/bu (see chart, source Bloomberg). Over the last decade-plus, in fact, grain prices have been generally higher and more-volatile than in the 40 or so years prior to the Global Financial Crisis (GFC).
The chart also has an orange line on it, which shows the US Cereal Crop Yield each year according to the World Bank.[1] I’ve inverted that series, so that when we are able to get more crops from each hectare, the line declines. It’s also on a logarithmic axis.
What causes changes in crop yields? Different planting and harvesting techniques are obvious improvements that are pretty much one-way. Also, improved fertilizers and pest control, and better use of the proper mix of fertilizers. But then why do crop yields sometimes decrease, if all of these things tend to get better over time?
One obvious answer to that is the weather. Less obvious is that the use of fertilizers isn’t constant. When fertilizer prices are high, farmers try to use less and that reduces crop yields. Also – and this is directly relevant to today – when there is a shortage of fertilizer then less of it is used and the price of fertilizer goes up. With the conflict in Ukraine and the cutting off of natural gas supplies to Europe (natty is an important input into the manufacture of some fertilizers), we are in that sort of situation. If we overlay real corn prices with real fertilizer prices[2] you can tell that these are closely related series.
Fertilizer prices have come down somewhat. The continued embargo of natural gas into Europe has only a small effect on fertilizer supply, and Russia only directly provides about 10% of the global supply of fertilizers.[3] But the overall level of commodity inputs into the manufacture of various sorts of fertilizer obviously impacts the output price. I suspect it will be a while before fertilizer prices even in real terms get back to their pre-COVID levels. And the overall CPI is not about to decline any time soon.
Does that mean that corn (and wheat, etc etc) prices can’t decline from here? Of course not – but my guess is that we’ve seen most of the good news on the agricultural commodity front for a while.