24 CIRCULAR NO. 126, BUREAU OP PLANT INDUSTRY. 



Irish potatoes have not been extensively grown, partly on account 

 of the frequent failures due to improper cultural methods. On the 

 experiment farm this crop has been very successful when properly 

 handled. It has been found that medium sandy soil is best, particu- 

 larly if it is old alfalfa sod. The land is thoroughly irrigated early in 

 January and plowed as soon after irrigation as possible. The potatoes 

 are planted between Januar}^ 15 and February 1 in rows 2h or 3 feet 

 apart, with the tubers 12 to 16 inches apart in the row. It has been 

 found desirable to harrow the soil frequently and to withhold irri- 

 gation water until the plants are about to bloom. One light furrow 

 irrigation at the time of bloomiug, followed by cultivation, is usually 

 sufficient to mature the crop. If irrigation water is kept off the field 

 after the crop reaches maturity the tubers can be harvested as wanted 

 for a period of six weeks. 



EUCALYPTUS. 



The protectmg levees on either side of the Colorado River are 4,000 

 feet apart. About 1,000 feet of this space is occupied by the river 

 channel. The remamder of the area between the levees is subject to 

 periodic overflows. It is desirable that as much of this land as is not 

 occupied by the river channel shall be covered with timber. It is 

 now covered with cottonwood and willow, neither of which is partic- 

 ularly valuable. It has seemed probable that some of the species of 

 eucalyptus might prove well suited to the situation and serve some- 

 what to hold the river to its channel and at the same tune furnish 

 useful timber. 



In 1910, 100 plants of eucalyptus, mcludmg the red, gray, and 

 desert gums, were planted on this overflow land. All three of the 

 species have done well, notwithstandmg a 3-foot overflow and ex- 

 tremes in temperature varying from 16° to 120° F. The red and 

 gray gums have attained a height of 24 feet and the desert gum a 

 height of 20 feet. These trees have had to compete with the rank 

 growth of native vegetation, consisting of cottonwood, willow, and 

 arrow weed. 



There are many waste areas on the project that could be profitably 

 planted to eucalyptus. On account of their deep-rootmg habit, 

 these trees obtain their moisture from the underground water and are 

 not dependent on irrigation. Every farmer would find it advanta- 

 geous to plant an acre or two if for no other purpose than to supply 

 fence posts and fuel. The eucalyptus trees are also desirable for 

 ornamental purposes. A row of the desert gum has been planted 

 around the experiment farm. 



[Cir. 126] 



