Question

What is the best pH of the soil for the cultivation of plants?
(a)3.5-5
(b)6.5-7
(c)4.5-8
(d)5.5-7

Answer 1

Hint: pH stands for ‘potenz of hydrogen’. It denotes the acidity or alkalinity of a solution. The pH of the soil for the cultivation of plants is ideally slightly acidic similar to weak acids.

Complete answer:
Most plants require an optimum pH of the soil for ideal growth. More acidic or alkaline soil may retard the growth of a plant and sometimes may even cause the plant to not grow at all.
Soil pH is important as it influences several factors affecting plant growth, such as soil bacteria and microbes, nutrient leaching and availability, toxic elements, and overall soil structure.
Bacterial activity releases nitrogen by decomposition of organic matter and certain fertilizers. This activity is particularly affected by soil pH too because bacteria operate best in the pH range of 5.5 to 7.0.
Plant nutrients leach out of soils rapidly with a pH below 5.0 as compared to the soils with pH between 5.0 and 7.0. Plant nutrients are generally more available to plants in the soils with a pH range 5.5 to 6.5.
The structure of the soil is affected by pH. In the optimum range, clay soils are granular and easy to work, whereas if the pH is either extremely acidic or alkaline, clay soil tends to become sticky and hard to work and hard to cultivate.
So, the correct answer is, ‘ 5.5-7.’

Note: Optimum pH is 5.5 to 7 for the cultivation of most plants but not all.
Some varieties of plants have adapted to the acidic or alkaline soils and hence they require soils with acidic or alkaline pH. Some vegetable plants like garlic or asparagus too have an optimum pH slightly alkaline with pH range from 6-8.