Problem 5 - Biology: The Dynamic Science

Question

Which of the following does not influence soil pH? a. rainfall b. hydroponic growth c. release of sulfur and nitrogen oxides into the air d. decomposition of organisms e. weathering of rock

Step-by-Step Solution

Answer

The factor that has no influence on soil pH is hydroponic growth.

Step 1: Analysis of Option A - Rainfall

Soil pH can often be influenced by the acidity or alkalinity of the rainfall in an area. Acid rain can decrease soil pH making it more acidic, while alkaline rain can increase soil pH making it more basic. Therefore, rainfall does influence soil pH.

Step 2: Analysis of Option B - Hydroponic Growth

Hydroponic growth refers to a method of growing plants without soil, by instead using mineral nutrient solutions in an aqueous solvent. Since there is no soil involved in hydroponic growth, it does not influence the pH of soil.

Step 3: Analysis of Option C - Release of sulfur and nitrogen oxides into the air

Sulfur and nitrogen oxides can combine with water molecules in the atmosphere to create acid rain. When this rainwater is absorbed by the soil, it can reduce soil pH. Thus, the release of sulfur and nitrogen oxides in the air does influence soil pH.

Step 4: Analysis of Option D - Decomposition of Organisms

The decomposition of organisms produces organic acids. These acids increase the acidity of the soil, thereby lowering its pH. Hence, the decomposition of organisms does influence soil pH.

Step 5: Analysis of Option E - Weathering of Rock

Weathering of rocks can release minerals into the soil that can either increase or decrease the soil's pH, depending on whether these minerals are acidic or alkaline. Therefore, weathering of rocks does influence soil pH.