466 IRRIGATION FARMING. 



to five inches higher than those not so irrigated, and 

 the dividing line marked by the water could be traced 

 up to the time of first cutting. In spite of the fadl 

 that evaporation was sufficient to remove nearly or 

 quite all of this water during the winter months, its 

 influence was felt far into the following growing season. 

 It must be understood by foreign readers that such a 

 wetting could be applied only to the extraordinary dry 

 soils of the arid region, where heaving out by frost ex- 

 pansion is unknown, and the writer very much doubts 

 if such pracflice would be advisable on the more moist 

 soils of the east. 



On land in the dry zone used for the produdlion of 

 cultivated crops, where the surface soil can be stirred 

 frequently to prevent loss of water by evaporation, 

 winter irrigation is far more effedlive than on grass 

 land. Such irrigation has been pra(5liced somewhat 

 successfully in Colorado and Utah by potato growers. 

 The fields are flooded before plowing and allowed to 

 dry to a tillable condition. This treatment insures 

 perfedl condition of soil for working and for the first 

 growth of the plants. The ordinary methods of cul- 

 tivation follow in this system without the application 

 of water until the plants are in bloom. In parts of 

 California, water supplied to the land during the win- 

 ter or wet season is often sufficient to mature crops, 

 although they may not receive any water between 

 planting and harvesting, and the same is true in Utah. 

 In such places complete and continuous cultivation is 

 pradliced to prevent the soil from losing its store of 

 moisture through evaporation. It is necessary to con- 

 tinually stir the surface to form a natural mulch. 



