The advent of chemical fertilizers led the farmers in a certain region to abandon the practice of periodically growin...

shunhe on October 2, 2020

Hi @Cammy,

Thanks for the question! So let’s take a look at this stimulus. We’re told that chemical fertilizers made farmers somewhere stop periodically growing a “green-manure” crop like alfalfa to rejuvenate soil. So the soil structure is poor. So, the argument concludes, to improve the soil structure, the farmers are going to have to stop using chemical fertilizers.

Now we’re asked for an assumption the argument relies on; in other words, this is a strengthen with necessary premise question. So we can use the negation test here. Let’s take a look at (D). Does the argument have to assume that chemical fertilizers themselves have a destructive effect on the soil structure of farm fields? Let’s assume that the fertilizers themselves don’t have such an effect. Is the argument weakened? No. The impact doesn’t have to be from the fertilizers themselves, it could just be because, as the argument says, the fertilizers lead to something else and thus have an indirect effect. So (D) isn’t necessary for the argument and thus the argument doesn’t rely on it, making it wrong.

Hope this helps! Feel free to ask any other questions that you might have.