SUBIRRIGATION AND SUBSOILING. 42 1 



thoroughly, the plant is never deprived of air and the 

 surface soil is kept loose and fine, and there is com- 

 paratively small waste, as the water rises slowly when 

 the cultivated soil is reached ; the temperature of the 

 soil is thus more uniform, and the growth of the plant 

 is not varied by changes in supply of moisture, air, 

 and temperature. It has been found by experiment 

 that subirrigated soil is warmer than that which 

 has been surface irrigated, and that the atmosphere 

 around plants to the hight of twelve inches is warmer 

 by subirrigation than by surface irrigation. Instead 

 of dilating at length upon the pro and con advan- 

 tages of subirrigation, the writer prefers to give a 

 description of the various methods of applying water 

 in this way, and allow the reader to form his own 

 conclusions as to the utility of the system considered 

 as a whole. 



Subbing. — This is the most natural method of sub- 

 irrigation and it is practiced without resorting to pipes 

 or artificial waterways. It is simply seepage, and is 

 possible only on sloping land having a clay subsoil 

 within a foot or two of the surface, and is quite com- 

 monly seen in the San L,uis valley of Colorado. 

 Wherever irrigation is necessary for the produdlion of 

 a crop, it will be found of great advantage at the time 

 of seeding to make ditches and furrows at short inter- 

 vals, and then to so check the water in these ditches 

 that it may stand in small bodies at a level above the 

 general surface of the ground to be irrigated. If the 

 water is held constantly in these small reservoirs during 

 the growing season, it will not be necessary to flood 

 the ground so often ; and if the soil is sufiiciently 



