120 AGRICULTURAL ENGINEERING 



land be irrigated following the sowing of the seed, the same 

 difficulties will be encountered as in the case of grain. 



The first thorough irrigation is usually given after the 

 crop shades the ground. After the first crop is harvested, 

 each subsequent crop is irrigated, as a rule, but once. Prac- 

 tice as regards the time of this irrigation varies in different 

 localities. Sometimes the water is applied perhaps a week 

 or ten days before the time of cutting. The intervening 

 time is necessary in order that the soil may be dried out suffi- 

 ciently to enable the mowing machine and hay tools to 

 operate successfully. In other localities it is practical to cut 

 the crop first and apply the water afterwards. 



Potatoes. Favorable conditions for the growth of 

 potatoes are to be found generally throughout the irrigated 

 regions in the United States. In the irrigation of potatoes, 

 care should be used not to irrigate oftener than is necessary, 

 as a low temperature is produced which is unfavorable to the 

 growth of potatoes. For this reason the minimum of water 

 is supplied, until the time for the formation of the tubers. 

 Potatoes seem to thrive best when the irrigations are few 

 but thorough, and cultivation is practiced to retain the 

 moisture between irrigations. 



Sugar Beets. About two thirds of the beet sugar 

 produced in the United States comes from the irrigated 

 sections, and it is one of the crops which can be very success- 

 fully grown by irrigation methods. Sugar beets are grown 

 over a rather broad range of soils, and irrigation practices 

 vary widely with different localities. Where the soil is open 

 and the winter season especially dry, winter irrigation is 

 practiced; but where there is sufficient amount of moisture 

 in the soil to start the crop, irrigation may be omitted 

 entirely before the time of seeding. The first irrigation is 

 generally delayed as long as possible, or as long as the beets 



