If it is not efficient it will cost more than it yields, a loss. According to FAO 70% of worlds land surface is not suitable for planting crops.

Cattle can transform grass, that we can't eat, to protein that we need. It is actually a good thing, especially if you can't grow anything there.

In Sweden we have something called ecological farming, it is certification, to be approved for ecological farming you can't use mineral fertilizers anywhere in your food production.

Ecological products are usually somewhat more expensive in the store.

Now there are of course lots of farms that is not classified as ecological and they can use mineral fertilizers or natural fertilizers.

About a third of all fertilizers for farming used in Sweden is natural.