SOILS. 



19 



Heavy soils are those in wliicli clay predominates. 

 They are difi&cult to work, and in dry weather often bake 

 like a brick, and are not permeable to dews or light rains, 

 but after heavy rains, become so saturated that they are 

 a long time unfit to work, and the plants often die from 

 excess of moisture. The crops, too, are full ten days latei 

 in coming to perfection than in a good sandy loam. Light 

 soils include those in which sands or gravel are the chief 

 ingredients. The water that falls upon these soils passes 

 instantly through them, so that the crops suffer quickly 

 from drought. In these, vegetation is earlier, but they do 

 not readily combine with manures, the soluble parts of 

 which are leached through into the subsoil, or are washed 

 out by the rains, so that if manure be constantly applied, 

 they will yield but a moderate crop. Gravels are, in this 

 respect, from the coarseness of the particles, generally 

 worse than sands. Sandy soils are better adapted to tap 

 rooted plants and bulbs, and for striking cuttings of all 

 kinds, while clays are better fitted for plants with fibrous 

 roots. 



In a garden designed for the cultivation of a variety of 

 plants, both a light sand and stiff clay are desirable. But 

 the best soil for general purposes, is a loam of medium 

 texture, arising from a suitable admixture of the two, as 

 they reciprocally correct the defects of each other, and 

 with the addition of organic matter, form a soil suited to 

 the cultivation of nearly all garden productions. Any soil 

 with judicious culture, draining, and manures, can be con- 

 verted into such a loam. 



If either of the above soils contain in its composition 

 a large quantity of lime, it is called a calcareous soil, 

 and is admirably fitted for the culture of fruit trees and 

 wheat. 



Aw alluvial soil is that formed by the overflow of streams, 



