WATER OF SOIL IN ITS RELATION TO PLANTS 201 



itself to such a fluctuation without a disturbance in its normal 

 development. Granulation has considerable influence on the 

 range of optimum moisture conditions, since the better the 

 granulation, the better able is the soil to accommodate itself 

 to changes in water content without a disturbance of normal 

 growth. In moisture conservation and control, a granular 

 soil is one of the first improvements to be aimed at. Drainage, 

 liming, addition of organic matter, and tillage, by leading up 

 to such a condition, increase the effectiveness and economy of 

 soil moisture utilization. 



Many of the ordinary farming operations have to do with 

 the maintenance of an optimum moisture condition in the soil. 

 During periods of excessive rainfall, especially during the 

 growing season, conditions should be such as to allow the pres- 

 ence of free water in the soil for the briefest time possible. 

 This means adequate under-drainage and satisfactory arrange- 

 ments whereby the run-off may be removed with but little 

 damage. Moisture control also demands conservation meth- 

 ods of more or less intensity in arid and semi-arid regions sup- 

 plemented by irrigation, whereby the soil-moisture may never 

 drop much below the point of lento-capillarity. By such ar- 

 rangments the optimum moisture conditions, so essential to 

 normal and uninterrupted crop growth, are maintained. 



