PT73.S2.Q20 - the advent of chemical fertilizers

sweezyseason

Hi guys I would appreciate it if someone could review my reasoning for this question and let me know if this is correct. When BRing I realized that I made a mistake and chose A rather than E which is correct.

Basically if negated, A says something along the lines of less than 51% of those people who abandon the use of chemical fertilizers will periodically grow alfalfa. Now this may be tempting but it doesn`t really do much, our argument doesn`t say that every person needs to make this switch, just that in order to improve the soil structure we need to ditch chemical fertilizers and begin growing green manure crops.

E is a much better answer because it tells us that we can`t use chemical fertilizers AND grown green manure crops, so we have to ditch chemical fertilizers as stated in the argument
When negated it sounds somewhat like, some farmers in the region will grow green manure even if they do not abandon the use of chemical fertilizers, suggesting that we do not need to ditch the fertilizers in order to grow green manure, and ruining our argument.

I also struggled a little with answer choice D, but here`s my reasoning
I think its incorrect because when negated it just says chemical fertilizers themselves do not have a destructive effect on soil, this can be true because the argument is assuming that its the switch from green manure to chemicals that has deteriorated the soil structure, it doesn`t need to be that the chemicals themselves are destructive.

Let me know what you think!
https://7sage.com/lsat_explanations/lsat-73-section-2-question-20/