The Soil and its Treatment. 7 



retentiveness, either of water or manure, whilst the opposite 

 extreme, a soil of close texture, due to a large proportion of 

 clay, is difficult to cultivate owing to its tenacity and " sticki- 

 ness " when wet. 



It is, therefore, easy to understand that a well-balanced 

 mixture of sand, clay, and humus known as loam is the best 

 soil, as not only can it be the most readily cultivated to suit 

 the needs of the majority of plants, but the roots can easily 

 work their way through it, and will find the necessary nutri- 

 ment better than in a very porous soil, which is liable to 

 become too dry, or in a close impervious soil, which in dry 

 weather may become too hard for the roots to work through 

 and in wet weather may become waterlogged. 



Subsoil. That portion of the soil which contains the mate- 

 rial for plant nutrition in an available form is, as a rule, seldom 

 more than a foot in depth, and is calculated to average no 

 more than nine inches. Below this comes the subsoil, of which 

 the composition and structure is of the greatest importance. 



When a loose porous soil rests upon a clay subsoil excessive 

 drainage is checked and the moisture retained is of great 

 benefit to plants ; or when a retentive clay loam rests upon 

 a well-drained gravel or sand drainage is accelerated and 

 the upper soil is relieved of surplus water. Either of 

 these conditions may be said to be good. On the other 

 hand when a sandy soil rests upon an open gravel or a heavy 

 loam rests upon an impervious clay the conditions are very 

 unfavourable, unless means are taken to make the former 

 more compact and " holding " and to improve the drainage of 

 the latter. . 



Drainage. The first and most imperative condition of soil 

 fertility is drainage, either natural or artificial. When land is 

 in need of drainage there is no work the cultivator can engage 

 in which is likely to give him so good a return for his labour. 



The principal effect of drainage is to free the soil from 

 stagnant and surplus water and to induce a passage of air 

 through it, aeration of the soil being indispensable to the 

 healthy growth of plants. If water cannot pass away freely it 



