PHYSICAL CONDITIONS OF THE SOIL. 



The one vital question that the irrigator must consider 

 no matter how much water he may have available is the 

 physical condition of the soil. Plants do not thrive on water 

 alone. A combination of the properties of air and water 

 together with heat and light are the resourceful elements 

 which we have, and nm?s be utilized in proper proportions 

 combined in the soil under proper conditions or we cannot 

 secure the large yields. It is folly for a man to own a tract 

 of land and in addition thereto to own a water-right, and 

 then to use them without securing to exceed one-half or 

 one-third of the best yield of that field; if he himself will 

 only do his part intelligently. The part which he must 

 play is that of preparing the soil, securing that ideal con- 

 dition which is illustrated in several of the previous chap- 

 ters by cuts. Following this is that all important part of 

 keeping the surface of the soil in condition to admit the air, 

 the importance of which is fully detailed under the head of 

 "Air in the Soil." At no time should the moisture that is 

 forced into the soil from the ditches by gravity be allowed 

 to return in any quantities to the surface and evaporate. 



It is through this upward movement of moisture by 

 capillary attraction that many of our fields which are under- 

 laid with a large per cent of alkali are ruined, this alkali 

 when in a soluble or dissolved condition rises to the sur- 

 face with the moisture in its upward movement by capillary 

 attraction, and as the moisture leaves in a vapor, the solid 

 alkali is left on the surface. 



Too much water is almost invariably applied to irri- 

 gating fields simply because we have been led to place all 

 faith in water and water only as the producing power. From 

 all our observations in irrigation, the reading of bulletins 

 and correspondence with people who have had yearc 



