32 LIFE ON THE FARM. 



considerable amount of the heat over night 

 Sandy soils are easily heated, but are not on the 

 average the warm^t. 



RELATION OF HEAT TO THE SOIL. 



The relation of heat to the soil is important. 

 All living things, both plants and animals, require 

 a certain amount of heat in order to live and grow, 

 With the higher animals, a great amount of heat is 

 necessary. The bodily temperature of man and 

 many other animals must be nearly 100 F. at all 

 times. If it rises a few degrees higher, or falls a 

 few degrees lower than this, death, or serious 

 results follow. Plants, like some of the lower ani- 

 mals, can endure greater changes of bodily tem- 

 perature; but there is a high and a low limit v beyond 

 which they cannot pass and live. If the bodily 

 temperature becomes either too high, or too low, 

 life-activity ceases permanently. 



Seeds germinate better in a warm than in a cold 

 soil. If the ground is too cold, they decay on 

 account of germs that can work at a lower tem- 

 perature. Some seeds sprout best at a temperature 

 of nearly one hundred degrees F. Good results, 

 however, follow with a soil temperature of 50 to 



75 F. 



For germination of seeds, and growth of young 

 plants, it is necessary for the soil to be warm to a 

 depth of a few inches only. As the plants grow 

 larger and send their roots down deeper, then 



