Question

Recent soil test form Nick’s farm showed that the soil has a pH value of 7.6, which means the soil is________ acidic, saline, or alkaline in nature. Adding____ sulphur, potassium, or nitrogen  to such type of soil can reduce its impact on plant growth.

Answer 1

Answer: a. alkaline b. sulphur

Explanation:

A pH is an indicator of acidity and alkalinity nature of a solution. The acidic solutions have low pH value and the basic solutions have high pH value. Some solutions are neither acidic nor basic they are called as neutral (pH = 7). Below the value of 7 the solution is considered to be acidic and above 7 considered to be basic.

According to the given situation, the pH value of 7.6 indicates that the soil is alkaline in nature. Adding sulfur to the soil will lower the pH of the soil. The soil bacteria in the soil will convert the sulfur into sulfuric acid. The accumulation of sulfuric acid in the soil will lower the pH of the soil. As, the plants growing in the alkaline soil are subjected to yellowing of the leaves and chlorosis.

Answer 2

Use this:

pH = 7 => neutral

pH > 7 => basic (alkaline)

pH < 7 => acidic

So, a pH of 7.6 means the soil is alkaline.

Now, to reduce the impact you should lower the pH.

Sulfur forms acid (H2S or H2SO4) which will lower the pH.

So, adding sulfur will result in the (at least partial) neutralization of the pH and so reduce the impact on plant growth.

Answers: 1) alkaline, 2) sulfur.