It looks like it could be herbicide drift.

It has nothing to do with the fertilizer. That is just coincidence. But if it isn't drift from herbicides being applied in the area (can drift for up to 1/2 mile) then next most likely culprit is the hay was contaminated with herbicide residue - an increasingly common problem.

A question and for future reference - nothing in that bed except composted horse manure? No soil? Trying to grow in straight compost is very problematic even under ideal conditions.

Dave

I was thinking that it could be the horse manure, but the hay is newer. As Dave says, if it isn't herbicide drift, it's the hay, or maybe the horse manure, as herbicides can go right through an animal and still cause problems. If you want to know for sure, and still have some of the manure and some of the hay, you could take some beans and try growing one in each. They are sensitive and will show problems in their leaves quite fast.

I have made veggie beds with aged manure over clay soil. No problems at all. The plants put their roots down into the clay, but enjoy the nutrients from the top 4" of aged cow manure :).

Linda

Sure does look like herbicide. If it isn't packaged as a gardening product, always ask about the history of the compost, manure, or hay/stray you get. As Dave says, herbicide contamination is rampant these days - clopyralids or picloram. The stuff is plant-specific. It'll kill broadleaf stuff, but not grasses. It's sprayed on a grass field to suppress those broadleaf weeds, and the foliage grown there is contaminated with it. But that herbicide also goes right through the digestive system of animals. It is preserved in compost made from that foliage or manure.

In fact, a few years ago, I got some cheap bagged no-name compost from a big box store, and the plants I applied it to all croaked. That no-name compost conspicuously disappeared from the big box store in a few months.

The stuff does break down by soil microbial action, so your bed is not permanently polluted. It'll be fine next year.