4 Southern Gardener^s Practical Manual 



(a) Drift, or coarse material which has been deposited 

 from water in motion. This fact is usually indicated by 

 the presence of water -worn pebbles in great variety and 

 distinctively different in character. This drift -deposit is 

 very clearly marked, in the southern states, along the 

 margin of the old ocean bed forming the dividing line 

 between the tertiary formation and the older land. 



(b) Alluvium, or soil deposited from still water, con- 

 spicuously manifest in river -bottoms, containing liberal 

 amounts of humus, light material easily floated so long 

 as the water was in motion. The fertility of such soils 

 as compared with that of uplands, which have been so 

 cultivated as to destroy the humus, emphasizes the 

 necessity of perpetuating the supply of this constituent 

 through the liberal application of coarse manures or a 

 judicious rotation of crops. 



AGRICULTURAL CLASSIFICATION 



Clayey soils are composed of very minutely divided 

 particles, which retard the free percolation of water. 

 For this reason, they remain wet long after rains. Since 

 much of the surface moisture is carried off by evapora- 

 tion — a cooling process — gardeners speak of them as 

 "cold" soils. Owing to the fact that they resist the 

 passage of the plow through them, they are spoken of as 

 "heavy" soils as distinguished from sandy or sandy 

 loam, although a cubic foot of sand is heavier than the 

 same volume of clay. Owing to this evaporation from 

 the surface, preventing access of air, the fine soil -par- 

 ticles contract and adhere to each other, thus causing 



