A Level Biology Practice Exam

What is soil depletion?

1. Increase in soil pH

2. The loss of soil fertility caused by removal of minerals

3. Improvement of soil quality through organic matter addition

4. Formation of new soil layers

The correct answer is: The loss of soil fertility caused by removal of minerals

Soil depletion refers to the loss of soil fertility, primarily due to the removal of essential minerals and nutrients that are vital for plant growth. When crops are harvested, they take with them minerals from the soil. If these minerals are not replenished through natural processes or human interventions like fertilization, the soil becomes less fertile over time. This decline in nutrient availability can hinder plant growth, reduce agricultural productivity, and negatively impact ecosystems. The other options are not accurate representations of soil depletion. Increasing soil pH does not necessarily relate to nutrient loss; it could influence the availability of certain nutrients but is not synonymous with infertility. Improving soil quality through the addition of organic matter is a practice aimed at countering soil depletion by enhancing its nutrient content and overall health. The formation of new soil layers suggests a geological process rather than a depletion of existing soil resources. Therefore, the definition that aligns most closely with the concept of soil depletion is indeed the loss of fertility due to mineral removal.