Iowa finds dead fish in 50 miles of fertilizer-contaminated river

[NickB79]

6. Liquid nitrogen? Do they mean manure slurry?

Because manmade nitrogen fertilizer is applied to fields as pressurized anhydrous ammonia from large tanks towed by tractors that literally inject it into the soil. If the tank ruptures, the ammonia vents as a gas, sometimes with lethal effect if the farmer doesn't get clear in time.

And Iowa has plenty of manure slurry from all the hog farms.