The article only mentions land value once, and in my opinion this is a huge oversight. There's articles going back to 2010[0] that speculate that a land bubble had been going for a few years, and when that's coupled with quantitative easing it means that people had to borrow increasing amounts of money to buy an equivalent amount of land. Combine that with decreasing crop prices and additional debt load that was taken on as a result of buying/fixing equipment, and you have a perfect storm.
[0] https://www.tandfonline.com/doi/abs/10.1080/1350485080229797...