Early this month I wrote about the decline of nighthawks, swifts and swallows and the parallel decline of their food supply, flying insects. Why are insects declining? In a comment Gene suggested that, in addition to insecticides, herbicides play a role. Here’s why that makes sense.
I’m a city person so farm practices are somewhat mysterious to me. Nonetheless, in the last 20 years I’ve noticed a change in how the fields look in the spring. They used to green up with the rest of the landscape but now most of them are brown and as empty as parking lots like the one shown above. There are no birds here, no swallows wheeling overhead.
The fields look different because herbicides are used to control the weeds. There are different poisons for different crops — for instance one for soybeans, another for corn — and the crops are engineered so they can grow in the presence of specific poisons.
Herbicides are a very labor saving device. When applied in the fall they keep the fields weed free all winter right up to spring planting. Consequently, the fields don’t have to be tilled (that’s why they look like parking lots). The absence of plants means there are no insects, another benefit for the crop.
As the growing season begins you can tell where herbicide has been used because there’s a stark mechanical line between treated fields and the neighboring untreated landscape.
Here’s a field where there are birds.
Yes, those plants are weeds. They will probably be treated with herbicide soon and the field will turn from green to yellow as they die.
Because of herbicides and insecticides, large scale farming takes less work. Millions of acres of U.S. farmland are truly empty now. No plants. No insects. No birds here.
p.s. As I say, I’m a city person and don’t know much about farming so if I’ve got it wrong please leave a comment to correct me.
(photos by Kate St. John)