RADICATION OF PLANTS. 27 



in the winter by horses (by no means an uncommon 

 occurrence in the foxhunting districts of England), so 

 far as to destroy every trace of a wheat-plant, and yet 

 next year's crop turned out much more abundant on 

 those very spots than in any other part of the field. It 

 is evident that, to outlive an attack of this kind, a plant 

 must have its principal roots spreading in the deeper 

 layers of the soil. In the developement of its roots and 

 the power of penetrating the deeper layers of the soil, 

 the oat-plant stands next to wheat, and will nourish in 

 a somewhat stiff soil ; but as in the superficial layers 

 also the roots of oats throw out a number of fine feed- 

 ers, in a lateral direction, it is necessary that the top- 

 soil should be rather light and open. A light, open 

 loam, even if of no great depth, is particularly suited 

 for barley, which forms a net-work of fine comparatively 

 short root-fibres. Peas require a loose soil, with little 

 cohesion about it, which will favour the spreading of 

 the soft root-fibres in the deeper layers also ; whereas 

 the strong woody roots of the horse-bean will ramify in 

 all directions, even in a heavy and more compact soil. 

 Clover, grass-seeds, and small-sized seeds in general, put 

 forth at first feeble roots of small extent, and require so 

 much the greater care in preparing the soil, in order to 

 ensure their healthy growth. The pressure of a layer 

 of earth half to one inch thick suffices to prevent the 

 developement of the seed sown in the ground. Such 

 seeds require only just as much earth to cover them as 

 will retain the needful moisture for germination. It is, 

 therefore, found advantageous to sow clover together 

 with corn of some kind ; for as the corn is earlier and 

 quicker in growth, its leaves shade the young clover 

 plant, and protect it from the too intense action of the 

 sun's rays ; thus affording more time for the extension 

 and developement of the roots. The nature of the 

 roots* of rapes, turnips, and tuberous plants, clearly 

 points out the part of the soil from which they draw 

 their chief supply of food. Potatoes are formed in the 



* Whenever the term ' root ' is used in this work, the underground 

 organs of plants are meant. 



