premise: crop rotation renews / protects soil sent2: crop rotation is a kind of process sent3: if something is decreased then that something is depleted sent4: renewing soil increases the nutrients in soil sent5: not doing something that is required for a process decreases the performance of that process sent6: if something increases something else, then decreasing that something will decrease that something else sent7: crop rotation requires rotating crops from year to year.
hypothesis: when crops are not rotated from year to year, the nutrients in soil are depleted