Commercial Gardening 



the land at better wages, and our wheat crops would be increased enor- 

 mously. Agriculturists would do well to consider the above figures before 

 smiling too broadly at them. 



The annexed diagram (fig. 88) will show at a glance the great advan- 

 tages to be secured by deep tillage. At A, where the soil is dug out 1 ft. 

 deep, the roots are restricted; at B, showing soil dug 2 ft. deep, a larger 

 mass of roots develop and absorb more food; while at c, dug 3 ft. deep, a 

 still larger mass of roots search the soil for food, and no matter how dry 



Fig. 88. Diagram showing the Root Development in Soil dug 1 ft. deep (A), 2 ft. deep (B), and 3 ft. deep (C). 

 The shaded portion shows the hard, impervious, and unbroken subsoil 



the summer may be the tender feeding tips are always in the midst of 

 plenty of food and moisture. 



9. WATER IN THE SOIL 



Water, being essential for all plant growth, must be present in suffi- 

 cient quantity in the soil, and in such a condition that it can be absorbed 

 by the roots. Water may be in such abundance in some soils that its 

 presence would be more harmful than useful to the crop. Thus in a 

 clayey soil that has been only broken up with the spade or the plough 

 from 6 in. to 12 in. deep there may be so much water present that the 

 soil becomes chilled and waterlogged, and plants fail to grow because the 

 soil bacteria remain inactive (see p. 125). 



The quantity of water in a soil depends upon the rainfall. This varies 

 in different parts of the United Kingdom from 24 or 25 in. in the 

 neighbourhood of London, and along the eastern counties of England 

 and Scotland, to 40 in. in the south-western districts; while in the 

 western Highlands, the Lake District, and parts of Wales the annual 

 rainfall is about 80 in. An inch of rain to the acre represents some- 

 thing over 100 tons of water to the acre; so that in the British Islands 

 the amount of water which falls upon an acre of soil varies from 2400 

 tons to 8000 tons annually. It penetrates the soil more or less readily 

 according to the nature of the soil itself, and the way in which it has 

 been cultivated, Thus on a clayey, uncultivated soil very little rain will 



