Question

What is the best pH of the soil for the cultivation of plants?
a) 3.4-5.4
b) 6.5-7.5
c) 4.5-8.5
d) 5.5-6.5

Answer 1

Hint: At this pH range plant nutrients, leach from the soil at a much faster rate, and most of the nutrients are available for plants.

Complete answer: The measure of the acidity or basicity or alkalinity present in the soil is referred to as soil pH. It is explained as the negative logarithm of the activity of hydronium ions, in a solution. pH is measured by using a pH meter. In soils, pH is measured by a mixture of a slurry of soil with water or a salt solution. Acid soils have a pH below 7 and alkaline soils have a pH above 7 and when pH is 7, it is considered as neutral. Ultra-acidic soils (pH < 3.5) and very strongly alkaline soils (pH > 9) are rarely seen.
Soil pH is considered an important aspect of soils as it affects many chemical processes. Mainly soil pH affects plant nutrient availability by controlling the chemical forms of the different nutrients and influencing the chemical reactions they undergo. For most plants, the optimum pH range is from 5.5 to 7, it is considered as optimum because this value is favorable for major plants. But some plants have adapted to thrive at pH values outside this range.

Additional information: Factors affecting the soil pH depend upon the mineral composition of the plant material of the soil.
Soil acidification is mainly due to rainfall, fertilizer use, acid rain, and oxidative weathering.
Soil alkalinity is mainly due to weathering of silicate, aluminosilicate, and carbonate minerals, the addition of silicate, aluminosilicate and carbonate minerals to soils, and addition of water containing dissolved bicarbonates.

So, the correct answer is ‘5.5-6.5’.

Note: Soil acidification is because of an increase in the concentration of hydrogen ions in the soil.