The Haber-Bosch process for producing anhydrous ammonia (slam nitrogen and hydrogen together at 200 atmospheres, heated to 400-500C in the presence of any of several metals, done over and over - 5% conversion per pass) is the definition of energy consumption. On top of that, the hydrogen feedstock is commonly natural gas - but to be fair, it could be water and a huuuge input of electricity for electrolysis.

From the article, use of ammonia first separates the nitrogen from the hydrogen (the bond that all that energy was used to jam together) so the hydrogen can be used in a fuel cell and so power a tractor.

It seems the advantage in using anhydrous ammonia is simply making hydrogen easier to store in energy-dense format at ambient temps.

I'd be interested to see how the carbon production works out. It's clearly not zero, but it might be an improvement of the diesels used in farm equipment.