The Science of the Soil 



117 



pass straight downwards. It will flow away from the surface to the 

 ditches, or remain in pools in the shallow places -just as it does on 

 roadways and pavements. On a sandy soil, the rain will pass down and 

 between the particles readily until it comes to the water-table beneath; 

 and in loamy or peaty soils a good deal of water will be absorbed. 



Different soils will absorb and retain water in 'different proportions, 

 as shown by the following experiment of Schiibler: 



TABLE SHOWING ABSORPTION AND EVAPORATION OF WATER 

 IN VARIOUS SOILS 



This is a laboratory experiment, and cannot therefore be regarded as 

 giving the same results as one would find in the open field, and in actual 

 practice. So much depends upon the way the soil has been treated. 

 Where the soil has been deeply dug or trenched far more water will be 

 absorbed than where it has been allowed to become hard and baked on 

 the surface. It therefore pays to cultivate the soil deeply and well if 

 full advantage is to be taken of the rainfall, and if the soil is to store 

 up sufficient moisture for the roots of the crops during hot and rainless 

 summers. 



The above table teaches the market gardener that a soil which has 

 been well dressed with organic material like stable manure, peat-moss 

 litter, &c., will absorb and retain moisture for a very long period but 

 only in accordance as to whether it has been cultivated to a great or 

 little depth. That is the important point for practical growers to bear 

 in mind. Unless the soil has been well opened up by digging, trenching, 

 or subsoil ploughing, it will lose its moisture very rapidly, and crops will 

 suffer intensely in consequence during a hot dry season. 



How Moisture is Lost. Soils lose moisture in four ways: (1) by 

 natural evaporation from the surface; (2) by bad and shallow cultivation; 

 (3) by transpiration from the leaves of the crops grown; and (4) by the 

 leaves of weeds allowed to grow. 



The loss by natural evaporation will depend upon the temperature of 

 the atmosphere and the dryness or otherwise of the season. The higher 

 the temperature and the drier the atmosphere the greater the evaporation 

 from the surface. This is so well known to gardeners who grow pro- 

 duce under glass that special care is taken to counteract the heat and 



