This past weekend everyone was out of salt and calcium chloride ice melting stuff, but one place was selling 10/10/10 (nitrogen, potash, phosphate: 10% of each) fertilizer as an ice melter.

I bought a couple bags of it and it did work fairly well.

I'm a science geek at heart, so am wondering 2 things:

1. Why would this fertilizer mix melt ice?

2. Is it as good as salt or calcium chloride?