498 ANNUAL EEPOETS OF DEPARTMENT OF AGRICULTURE. 



States in which such districts have been estabhshed and a report sub- 

 mitted for pubhcation on ''Irrigation District Development in the 

 United States." 



HydrauHc experiments have been continued at the Fort Collins 

 (Colo.) laboratory and at the field laboratory near there. Especial 

 attention has been given to evaporation experiments, but these 

 studies have not yet been carried far enough to warrant publication 

 of the results. Several of the new current meters devised by a member 

 of the division have been constructed and sent out for use under field 

 conditions. 



The division has continued to render assistance to communities in 

 the organization of irrigation and drainage districts, having for their 

 purpose the reconstruction or improvement of existing systems or the 

 installation of new works of irrigation or drainage. This is considered 

 an important phase of the work, as mistakes made in the initial stages 

 of organization sometimes lead to serious difficulties and even failure 

 of a project. 



It is not generally known that the cost of securing a water supply 

 for arid land, including the building of storage reservoirs, divei'sion 

 dams, canals, and other works necessary to bring the water to the 

 farm, is frequently less than the farmer's expense in preparing his land 

 for irrigation, building the necessary improvements, purchasing 

 equipment, etc. This is one of the rather surprising facts brought 

 out by data which have been collected recently relating to the cost of 

 irrigation water and the cost of establishing an irrigated farm. The 

 study of the cost of irrigation water has thus far been confined to the 

 State of California, but the investigation as to the cost of establishing 

 an irrigated farm has covered the entire West. The results when 

 available will be of assis'tance to new enterprises and to prospective 

 settlers on irrigated farms. 



FARM-DRAINAGE INVESTIGATIONS. 



In the field of agricultural drainage the problems that may be 

 studied with profit are many and varied. A few of these stand out 

 because they affect so directly and obviously the pocketbook of the 

 farmer. It is to this latter class that the bureau must confine 

 itself. 



These basic projects, from their very nature, must continue from 

 year to year. Consider, for example, the matter of depth and spac- 

 ing of tile drains. Shall the farmer of the fine sandy loams of North 

 Carolina space his tile lines 100 feet or 135 feet apart? In this 

 decision is involved a matter of some SIO or $15 per acre drained. 

 Studies made in Pitt County, N. C, during the last two years have 

 showm that the wider spacing is satisfactory. Plainly, however, this 

 determination for the sandy soils of the Coastal Plain of North 

 Carolina will not apply to the close clay soils of the Mississippi 

 Delta country. The fact is that the opportunities for studies along 

 this line are as numerous as are the types of soil and the variations 

 in rainfall. To the extent that resources will permit, these investi- 

 gations will be continued with respect to other soil types and 

 localities. 



One of the advantages that has long been claimed for tile drains is 

 that they "warm" the soil. While it is not difficult to arrive at this 



