THE IRRIGATION AGE. 33 



cause you have two or three times as many square inches of surface in 

 a cubic inch of soil. The increase or decrease in the lifting power of 

 loose or firm soil may be very clearly illustrated by the use of differed 

 size glass tubes. In a bunch of thirty tubes used to illustrate this 

 point in our lecture last winter the largest was one-tenth of an inch in 

 diameter inside and the smallest about the size of the human hair. 

 These tubes were six and one-half inches long. While water would rise 

 only one quarter to three-eighths inch up the larger tubes; it would go 

 clear to the top in the smaller ones, showing that water may be lifted 

 by capillary attraction to the height where gravity or the weight of 

 water equals surface tension. As shown by the tubes, the quantity or 

 weight of water inside the lubes is diminished faster than the inside 

 surface of the tubes, or they grow smaller; therefore, the water is 

 raised higher in the smaller tubes, thus showing that firming soil in- 

 creases capillary attraction, thus increasing moisture in firmed soil 

 over loose soil. Therefore, we find it important to have the soil firm 

 where the roots are. There is one important action of water in scien- 

 tific irrigation after the ground is plowed; water is turned on in the 

 fall, the soil in a saturated state becomes dissolved, and the little par- 

 ticles become closely settled together in the lower portion of the fur- 

 row slice; all little cavities are filled by these dissolved particles. 

 Their action is shown by the general plan adopted in filling deep 

 ditches dug for water mains; etc., especially where soil is of a loamy 

 formation. It would be impossible .to ge^ all the soil back into the 

 ditch without the application of water to dissolve and settle the par- 

 ticles. It is also important in scientific irrigation to keep the surface 

 soil loose and dry by constant shallow cultivation to prevent evapor- 

 ation and admit air. When this is well done the growth of the plant 

 is almost marvelous and has always been found to make a more rapid, 

 healthy growth than under any other plan. This being true, it gives 

 us the key to some important facts, viz.: That roots make the most 

 vigorous growth in firm, moist soil; that by having the lower portion 

 of the furrow slice firm, moisture is kept in greater supply for the 

 roots, and is also drawn more rapidly up to supply the plant during 

 excessive hot days, for it is these critical days that may increase or 

 decrease your crop yield many bushels. With plenty of moisture at 

 the roots, the excessive heat means increased growth, while a slight 

 shortage means exactly what short feed means to your cattle. One of 

 the most important lessons learned by our scientific irrigators is the 

 value of frequent shallow cultivation, which we will explain in a 

 future article. 



