65 



])r()p(M- size in the supply ditcli. 'I'lic canals were measured at rating 

 tluines ])laced near the point of diversion, the \xdocity beinj^- deter- 

 mined hy a eurrent meter. In tiie (Jalhitin Valley the fluctuations in 

 the water levels of both the small ditches and the canals were meas- 

 ured and recorded by a rl^cordino- instrument, but in the Bitter Root 

 ajid Yellowstone valle3^s no instruments were available, and daily obser- 

 \ ations were made of the heio-lit of water at the several o-aug-es by the 

 ilitch riders, who kej)t the records in a book provided for that purpose. 

 In fenced fields the area contained within the fence lines was taken, 

 but in smaller fields only the area cropped, together with the space 

 occupied b}' the head ditches, was included. The area of land under 

 most of the canals investigated in the Bitter Root Valley was found 

 by actual survey. From 1881> to 1901, inclusive, on account of the 

 Uuk of funds, no surveys were made of the Yellowstone or Gallatin 

 Valley canals. The total area irrigated under each canal was com- 

 puted from estimates obtained from the owners by a house-to-house 

 canvass. In 11)02 careful surveys were made of the irrigated lands 

 under each canal, thereb}^ checking the estimates of previous years. 



THE QUANTITY OF WATER APPLIED TO INDIVIDUAL CROPS. 



MEASUREMENTS MADE IN 1891). 



In 1899 an eti'ort to determine the duty of water in the Gallatin 

 Valley was made by the irrigation and drainage investigations of the 

 Office of Bxperiment Stations. United States Department of Agricul- 

 ture, in cooperation with the Montana Experiment Station. In 

 selecting the fields care was taken to have them rep'.-esent as neai-ly as 

 possible the average conditions of that vicinity. No attempt was 

 ever made to control the amount of water used. The farmer was free 

 to use as much water as he deemed necessary. The work for tho first 

 season consisted in determining the amount of water applied to eight 

 tiekls and the duty of water under ^Middle Creek canal. Five of the 

 field tests were made on the station farm and the remaining three on 

 adjacent farms. Descriptions of these fields were published in a 

 former bulletin." The soil in general consists of a clay loam from 30 

 to TO inches deep, with a porous stratum of gravel wash beneath. No 

 water was used on any of the eight fields before June 17, 1899, and on 

 that date the irrigation of a field of red clover was begun. It was 

 June 23 when the first of the seven grain fields was irrigated, and no 

 water was applied on these after July 26. The last watering of the 

 clover field took place August 2; In the following table are given 

 for each field the number of acres irrigated, the yield per acre, the 

 rainfall during the period of growth, and the duty. 



«U. S. Dept. Agr., Office of Experiment Stations Bui. 86. 



