12 THE SOIL OF THE FARM. 



soil, being all dependent npon its mechanical condition. 

 And this influence is not confined to the first stage of 

 vegetation, for at no period of growth or maturity can 

 the plants avail themselves of their full amount of food 

 unless the sta|;e of the soil admits of the free passage of 

 air and water, and favors the extension of the roots in 

 all directions. 



Texture of Soils. — In this respect the soil may vary 

 from coarse pebbles or loose sand to the finest and most 

 tenaceous clay. In general, however, those soils are best 

 adapted for agriculture which consist of mixtures of sand 

 with a moderate quantity of clay, and a little vegetable 

 matter. When sand or other coarse material predomniates, 

 the soil is light and easy to till, and will grow all the 

 crops suitable to the district; but it is deficient in the 

 power of retaining water and the soluble and volatile 

 parts of manure. When clay is in excess, the soil is 

 heavy to till, and will probably grow fewer crops; it is 

 too retentive of water, is not easily w^armed, does not ad- 

 mit of access of air, and consequently does not facilitate 

 those chemical changes in the soil and manure placed 

 in it, which are necessary to prepare proper food for 

 plants. 



Clay lands, whether in the dry or WTt state, are the 

 most difiicult to work; sandy soils and those containing 

 much organic matter being the most easy. AVhen land is 

 worked in a wet state, we have not only to overcome the 

 cohesiveness of the particles among themselves, but at 

 the same time their attachment or adhesion also to the 

 agricultural "implements employed. In a wet climate, 

 therefore, the working days for tillage will be fewer than 

 in a dry one, and proportionately more so on clay soils 

 than on liHit soils. Less work can also be done in a day 

 with the same power on clay and heavy soils than on 

 sandy or light ones. On clay lands, a i)air of horses can 



