Question

A fertile soil is likely to have a pH value of
A.3-4
B.8-9
C.6-7
D.10-11

Answer 1

pH is the scale which is logarithmic and can inversely determine the concentration of hydrogen ions in the solution. This is because the formula which is used to calculate the pH will approximate to negative of the base 10 logarithms of the molar concentration of hydrogen ions in a solution. To be precise pH is negative to the base 10 logarithms of the activity of the hydrogen ions.

Complete step by step answer:
The pH of the soil is a measure of basicity or the acidity of a soil. pH can be defined as the negative logarithm of the hydronium ion concentration.
To measure the soil pH it is made into a slurry where the soil is mixed with water and this will normally fall under the pH value between three to ten, with seven being neutral. If the soil is acidic the pH value will be below seven and if the soil is alkaline or basic the pH value should be above seven.
The soil pH is considered a master variable because it affects many chemical processes. When there is a slight change in soil pH it affects the plant nutrient availability by controlling the chemical forms of the different nutrients and they also influence the chemical reactions which they undergo.As the soil pH decreases most desirable crop nutrients become less available while others, often undesirable, become more available and can reach toxic levels. The optimum range for the plant pH is between 5.5 to 7.5 but many plants have adapted to grow in extreme pH conditions.
Hence the correct answer is option D, 10-11.

Below is the picture of pH scale.

Note:
The soil pH is very important because it influences many factors that affect plant growth such as (1) nutrient leaching, (2) soil bacteria growth, (3) toxic elements, (4) nutrient availability, and (5) soil structure.
The organic matter which has been released by the activity of some bacteria is used as a fertilizer and this will be affected if there is a change in the pH, because bacteria function very well in the pH of 5.5 to 7. The plant's nutrient will leach out if the pH is below 5. The plants will receive nutrients from the pH of 5.5 to 6.5.