Unless we change course, the US agricultural system could collapse | Agriculture | The Guardian
https://www.theguardian.com/commentisfree/2020/aug/26/us-farming-agriculture-food-supply-danger
Interactions between Native Americans, plants, animals, microbes and climate left behind a majestic store of fertile topsoil that scientists call mollisol. Even today, the US midwest boasts the largest of four major mollisol stores on the planet. Mollisols develop over millennia yet can be squandered in decades. US colonial-settler agriculture transformed this ecological niche, a land mass 1.5 times the size of California, into a factory churning out just two crops – corn and soybeans.
This kind of agriculture fouls water as a matter of course. Since corn and soybeans are planted in the spring and harvested in the fall, the vast majority of corn-belt farmland lies bare for the winter months, leaving the ground naked when storms hit. These deluges pummel bare topsoil and send it – and the agrochemicals and manure farmers apply to it – cascading off farms and into streams and creeks that flow into rivers, lakes and ultimately the Gulf of Mexico. But there’s another problem with subjecting the land to the same two crops every year: loss of the region’s precious black topsoil. According to research by the soil scientist Rick Cruse, Iowa – and much of the surrounding corn belt – is losing soil at a rate 16 times the pace of natural replenishment.
Again, climate change is a driver. Today’s farmers encounter a weather regime radically different from that of their grandparents: more intense off-season storms, and thus ever-heavier pressure on the soil. If global greenhouse gases continue rising, the region faces a 40% increase in precipitation by the late 21st century, according to the Fourth National Climate Assessment. The soil that makes one of the globe’s most important growing regions so productive is vanishing before our eyes, degrading a crucial food production region at the very time when climate change and global population growth call for building resilience.