Question

Fertility of soil is reduced by:

• A. Decaying organic matter
• B. Crop rotation
• C. Intensive agriculture
• D. Addition of $N_2$ fixing bacteria

Answer 1

The correct option is C Intensive agriculture

• Soil fertility decreases when the quantities of nutrients used by plants for their growth exceed the quantities of nutrients that returned to the soil.
• Intensive agriculture focuses on increasing agricultural productivity, by using an excessive amount of chemical fertilizers that alters the natural cycling of nutrients in the soil, kills beneficial insects and plants further reducing the fertility of the soil.
  
• While decaying organic matter, crop rotation, and the addition of nitrogen-fixing bacteria increase the fertility of the soil.

So the correct answer is option C.