MIXTURE OF SOILS. 149 



injurious matter is known, or thought to exist, the 

 mixture of the strata should not be effected until 

 the drains have run for a few months to temper 

 them, and reduce these elements of injury to those 

 of fertility. 



The result of the mixture of soils will be consid- 

 ered under our next subdivision. 



3. By deep pulverization soils become mixed. 

 We agree with Mr. Johnston, that many soils are 

 deficient in some qualities which are necessary to 

 productiveness. Thus humus abounds to an excess 

 in peaty soils, and an addition to their earthy sub- 

 stance is a means of improvement. This is under- 

 stood by farmers, and therefore sand or gravel is 

 applied with good effect ; and likewise muck or 

 clay is carted uj)on and mixed with porous soils, 

 and sand with tenacious earths. This alters their 

 physical condition. It makes the clay more open, 

 and the peat and sand more tenacious. A chemical 

 as well as a mechanical change is effected. Often- 

 times a soil is barren which contains all the ele- 

 ments of fertility, with a single exception. Thus 

 some lands require lime, which they might secure 



if the substratum should be mixed with the cul- 

 tivated soil. Earths are often mixed by surface 



