THE CARE OF THE SOIL. 



23 



whole business of agriculture is founded upon the soil," and we have 

 many times referred to it as the growers' raw material. All wealth 

 proceeds from the soil, for it we pay rent or its equivalent, in it 

 the plant grows, and from it (with or without the aid of manures) the 

 plant draws its nourishment, or at all events that part of it with which 

 we are concerned. 



, It is undoubtedly true that on capacity and skill in managing the 

 soil depend to a large extent the quality and quantity of the crop. 

 Surely then the soil is a thing to study — to watch, understand, and 

 treat with all the available aid of practice and science. 



Everybody knows that soils differ widely : the difference in rents 

 paid is an acknowledgment of the fact. It is impossible to obtain 

 either the weight or quality from some soils that may be confidently 

 expected from others. The soil may be heavy or light, and there are 

 innumerable variations between these two extremes. It is obvious 

 that these soils require different treatment in cultivation and manage- 

 ment, in manuring and in cropping. In order properly to manage 

 the soil these differences must be studied, and reasons ascertained for 

 any inferiority in order that defects may be, if possible, remedied. 



The study of the soil, and the part it plays in the nutrition of the 

 plant, falls naturally under three headings — the mechanical or physical, 

 the chemical, and the biological aspect. Each of these headings could 

 easily form the text for a separate paper, but it is only intended to 

 glance at them in order to point the necessity for the care of the soil 

 advocated, and to suggest the manner in which it may best be under- 

 taken. 



Mechanical. 



Origin of Soils. — In order to understand the soil mechanically it 

 is necessary to know something of its origin. As is well known, soils 

 are formed by the disintegration of the rocks that compose the earth's 

 surface. These rocks have been deposited under widely varying 

 conditions and by many different agencies : great heat, extreme cold, 

 violent convulsions, the action of glaciers, the submerging of the land 

 under water, and all the many changes, climatic and otherwise, that 

 the earth has undergone, have played their part. 



The study of these phenomena and the classification of the various 

 rocks according to the manner and period of their formation belong 

 to the science of Geology, and it is not intended here to write a treatise 

 on this fascinating science. It is sufficient for our purpose at the 

 moment to remember the facts above referred to, as they explain the 

 great variation of soils, both mechanical and chemical, which is the 

 first point to which it is desired to draw attention. Except in the 

 cases of soils of transportation— that is, soils that have been carried 

 from above the rocks from which they were originally formed, e.g. 

 " alluvial " soils— it stands to reason that the soil overlying a certain 

 formation will bear a definite relation to the rock from which it derives 

 its origin. 



