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  • Smart Learning for All

  • Topic: pH value.

  • Why is pH value important to a farmer?

  • What is happening to the tree?

  • Is it merely because of pH?

  • Yes, you are right.

  • pH is the measure of acidity or basicity of a substance.

  • It is expressed by positive numbers ranging from 0 to 14 where 7 indicates a neutral value.

  • Neither acidic nor basic.

  • When the pH value of a substance is below 7.

  • It is termed as acidic and when it is above 7, it is termed as basic.

  • The pH value of ideal soil is usually close to neutral.

  • It ranges from about 6.5 to 7.5.

  • If we don't maintain this pH, growth of most of the plants is adversely affected.

  • Are you shocked?

  • Did the white marble just turn yellowish brown due to acid rain?

  • Yes, you are right.

  • The pH of rainwater is about 5.6.

  • This means that rainwater is slightly acidic.

  • This slightly acidic nature of rainwater does not really cause any damage.

  • But, in last few years, many harmful substances are being released into the atmosphere.

  • Addition of these substances drops the pH of rainwater.

  • In certain cities, the proportion of these harmful substances is so high in the atmosphere.

  • That it drops the pH of rainwater to a much lower level making it strongly acidic.

  • When this strongly acidic rainwater falls down, it is termed as acid rain.

  • This acid rain not only discolors white marbles, but also harms human beings and animals in several ways.

  • Did the plant just turn yellow?

  • Why do you think this happened?

  • The plant turned yellow due to increase in pH value of the soil.

  • A pigment named chlorophyll gives a plant its green color.

  • The plant prepares chlorophyll with the help of iron.

  • When the plant absorbs water from soil.

  • It also takes in iron present in that soil and prepares chlorophyll.

  • However, when the pH of soil increases, that is, when it becomes more basic, the availability of iron decreases.

  • As a result, the plant does not get the required amount of iron to make chlorophyll and hence, it turns yellow.

  • Also, besides the availability of iron.

  • pH value of soil also affects the level of toxic substances, growth of bacteria and roots, etc.

  • Thus, when a farmer has to grow any crop, he has to know the value of pH of his soil for a good yield.

  • Otherwise, his crop will face undesirable consequences.

  • Ultimately, he may suffer a great loss.

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