NJ Explains: The Rain on the Plains, Mainly to Blame?
Nathanael Johnson starts us off with some good news.
As you can see, farmland has leveled out at about 75 percent. But erosion has gone down. The most interesting part of that first graph, to me, is the far right-hand side: There’s been less topsoil washing down the Raccoon River in the last two decades than at any other time. Or at least any other time on this record: If you go back before European settlement, there was very little erosion on the prairie. But still, for the period in which anyone was farming, the modern farmers look like the best stewards; the year with the lowest recorded sediment loss was 2000.
But point out that in other parts of Iowa high corn prices have driven the kind of fence row to fence row plant that results in stream and creek bank erosion. The disheartening thing we learn is that while the USDA has spent billions on agricultural conservation efforts and farmers have made great strides, climate change erases many of those gains.
And then there’s the weather. A huge part of the erosion and water pollution that occurs each year can be traced back to one or two big storms — gully washers that rut fields. And we are seeing more of these big weather events, as abnormal becomes the new normal. “We claim improvement in a dry year, and then the sky is falling in a wet year,” said Keith Schilling at the Iowa Geological and Water Survey, who co-wrote the Raccoon River study that got my attention.
As Roseanne Roseannadanna used to say, “It’s always something.”
So, while we should give credit and encouragement where it’s due, in sum we’re still polluting with our food system.
What’s the solution? In a word, plants: Plants sheltering the earth during the big storms; plants slowing raindrops with their leaves; plants holding down the earth with their roots. In places, people have begun to restore critical sections of the old prairie. There was once 167 million acres of tall-grass prairie in the land where we now grow corn and soybeans, and less than .1 percent of that prairie remains.
When I asked Eugene Turner, a professor at Louisiana State University, about this, he sent me the Marsden Farm study, which offers a potential way to mimic the prairie while still turning a profit. Researchers mixed things up by adding some grasses into the usual rotation of corn and soy.
Successful demonstration projects like this are sometimes hard to scale — it’s a lot easier to get results when you have a team of researchers scrutinizing the fields than if you are just one farmer trying to figure it out as you go along. And in recent years farmers have been pushed by a strong market incentive to just plant as much corn as possible. But as corn prices come down, perhaps more farms will look for alternative methods.
Read the whole thing. There are good links and interest charts as well.