Step 1: Confirm (A): cover cropping is a well established organic-farming practice, true.
Step 2: Confirm (R): cover crops improve soil health, suppress weeds, and raise biodiversity, true.
Step 3: Test the link: organic farming avoids chemical inputs, so it depends on exactly these biological benefits, meaning (R) is the direct cause of (A).
Step 4: Both statements are true and R explains A, matching the first option.