Soil temperature is one of the important factors that control the microbiological activity and all the processes involved in the growth of plants. Heat is necessary for seed germination, root growth and other biological activities.

The temperature needed for germinaton and root growth varies with crops and varieties. Crops, e.g. wheat , barley, and peas grown in India during winter germinate at relatively low temperatures as compared with maize, and those at which groundnut or cotton germinate. Microbiological activities are retarded by low soil temperature. As a result, the nitrification processes in the soil are slowed down and plant nutrition and growth adversely affected.

Soil temperature is to be considered so important that in the soil taxonomy there is a provision to use it as a differentiating criterion at the family level of categorisation.

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