6 The Profitable Culture of Vegetables. 



For our present purpose, however, this is unimportant. By 

 their life, death and decay, lichens assisted in soil formation 

 and made the existence of mosses possible. The latter in like 

 manner added to the bulk, and were in turn followed by more 

 highly-organised plants and then by animals, and as each of 

 these in turn grew, died and decayed, the mass was gradually 

 increased and more or less perfect soils were produced as we 

 know them to-day. 



Composition of Soils. The pulverised rocks which thus 

 form the base of all soils consist of various mineral or inor- 

 ganic compounds, whilst the remains of animals and plants, 

 consisting of organic compounds, form the remaining portion. 

 This admixture of inorganic and organic material contains, in a 

 crude form, the foodstuffs which plants absorb from the earth. 

 When soils are chemically analysed it is seen that all bear a 

 certain resemblance to each other in their composition, so far 

 as the ingredients are concerned. There is, however, a very 

 wide variation in the relative proportions of these ingredients, 

 and it is this variation which makes all the difference between 

 the many kinds of soil with which cultivators have to deal. 



Soils are classified according to the predominance of the 

 clay, sand, lime, or vegetable matter which they may contain, 

 as follows : 



Clay soils containing above 50 per cent. clay. 



Clay loams ,, 30 to 50 ,, clay. 



Loamy soils ... ,, 20 to 30 ,, clay. 



Sandy loams ,, 80 to 90 ,, sand. 



Sandy soils ... ,, over 90 ,, sand. 



Marly soils ,, 5 to 20 ,, lime. 



C ch C alk e y 8oils } - above2 " lim0r Chalk ' 



Vegetable or ) above 5 humus, or 



peaty soils j decayed vegetable matter. 



Every known soil falls within the limits of one or other of 

 the above classes, or of their gradations, although there are 

 many intermediate variations between one type of soil and 

 another. 



The fertility of any soil is intimately connected with its 

 composition and texture, apart from any plant foods it may 

 contain. A soil of open texture due to a large proportion of 

 sand, gravel, or chalk is easy to cultivate but has very little 



