KINDS OF SOIL 69 



that the people are afraid to touch requires no more 

 remedy than thorough, deep tillage, maintained 

 at all times." Liberal dressings of manure, espe- 

 cially horse manure, are very beneficial. 



Alkali soils are apt to be deficient in nitrogen, 

 because the nitrogen-fixing germs are not able to 

 do their work when there is much alkali present. 

 It is stated by Snyder that if a few loads of soil 

 from fertile land are sprinkled on alkali spots the 

 beneficial germs will be introduced and much good 

 will result. After steps have been taken to remove 

 the excess of salts the land should be cropped first 

 with plants that are not very impatient of alkali. 

 Oats is considered one of the best crops for this 

 purpose. 



Practically all farm soils contain some alkali, 

 but wherever rainfall is plentiful the salts are 

 washed away before they accumulate sufficiently 

 to injure plants. A very little alkali in a soil is 

 beneficial. In fact, it is necessary to apply lime to 

 some acid soils in order to make them sufficiently 

 alkaline to be most productive, as is noted in 

 Chapter XIV 



THE SUBSOIL 



The soil immediately beneath the richest part of 

 the surface soil is called the subsoil. It may be of 

 any depth, and extends to the underlying rock. 

 The distinction between the soil and the subsoil, 

 as the two names are commonly used, lies almost 

 entirely in the colour and texture, due to the 

 greater amount of humus near the surface. In 

 cultivated land there is usually a more or less dis- 

 tinct line between the rich, black surface soil and 

 the poorer and lighter-coloured subsoil. In most 



