SOIL WATER 



SOURCES AND FORMS OF SOIL WATER 



The soil which is occupied by the roots of plants 

 receives moisture in the form of rain, snow and 

 dew from above and free and capillary water rising 

 from below. 



" Free water is that form of water which fills our 

 wells, is found in the bottom of holes dug in the 

 ground during wet seasons, and is often found 

 standing on the surface of the soil after heavy 

 or long continued rains. It is sometimes called 

 ' ground water ' or ' standing water,' and Hows un- 

 der the influence of gravity." Free water is not 

 used directly by plants unless they are swamp plants, 

 and its presence within eighteen inches of the sur- 

 face is injurious to most farm plants. Free water 

 serves as the main source of supply for capillary 

 water. 



" Capillary water is water which is drawn by 

 capillary force or soaks into the spaces between the 

 soil particles and covers these particles with a thin 

 film of moisture." It is a direct source of water to 

 plants. Capillary water will flow in any direction 

 in the soil, the direction of flow being determined 

 by texture and dryness, the flow being stronger 

 toward the more compact and drier parts. If the 

 soil is left lumpy and cloddy then capillary water 

 cannot rise readily from below to take the place of 

 that which is lost by evaporation. If, however, the 

 soil is fine and well pulverized, the water rises freely 



