I have been learning how to use some free software called Geoda. Frankly, it is not easy! So far I have constructed two cartogram of arable rent and wheat yields. Cartograms aren't really maps: they represent quantities of interest. Here they are:
The top one is wheat yield and the bottom one is rent. I find it interesting that the red dots don't match: red represents a large positive outlier, green represents normal. So we have quite a few instances of high rents, but rather fewer of high yields. So some landlords were extracting high rents when the yields were only normal. Now, let's not get too carried away with blaming landlords: there might have been other factors, such as closeness to the market. Anyway that is something to test.