I'm not sure if UFOs had anything to do with it, but from the research I've done on herbicides, some are water soluble. This means that they can evaporate with water, be collected in rain water clouds, and then be dispersed throughout an area. If you have neighbors using herbicides, it's quite possible this happened. It's a really big and unspoken problem, especially since these chemicals can poison ground water and local ponds and lakes. Just some fruit for thought. I'd suggest should and water testing in the area. Truth is, if it's affecting the soil, it's probably affecting you too.
I'm not sure if UFOs had anything to do with it, but from the research I've done on herbicides, some are water soluble. This means that they can evaporate with water, be collected in rain water clouds, and then be dispersed throughout an area. If you have neighbors using herbicides, it's quite possible this happened. It's a really big and unspoken problem, especially since these chemicals can poison ground water and local ponds and lakes. Just some fruit for thought. I'd suggest should and water testing in the area. Truth is, if it's affecting the soil, it's probably affecting you too.