Our World in Data has, well, the data in their Crop Yields Data Explorer. For example, here is a chart of cereal yield for a few countries. With the crop yields data explorer you can select from most countries, different crops, and different measurements. In each case the data can be downloaded, as well as the chart.
Tags charts and graphs data source
How expensive is fertilzer?
The world ban blog looks at fertilizer prices in the post Fertilizer prices ease but …