[Cir. 127— A) 



THE WORK OF THE DELTA EXPERIMENT FARM IN 1012/ 



By John P. Irish, Jr., Farvi Superintendent, Office of Western Irrigation Agriculture. 



INTRODUCTION. 

 DESCRIPTION OF THE REGION. 



The Delta Experiment Farm is located on the Lower Jones Tract, 

 one of the islantls in the south-central portion of the San Joaquin 

 Delta. The tract is typical of the general San Joaquin Delta lands. 

 The soil is a very light peat, characteristic of most of the reclaimed 

 land on the San Joaquin, side of the delta. 



These lands lie at sea level and before their reclamation were 

 flooded during the major portion of the year. The delta of the com- 

 bined Sacramento and San Joaquin rivers occupies an aggi-egate 

 area of about 250,000 acres. 



Reclamation is accomplished by leveeing to exclude tidal and flood 

 waters and by the installation of ditches and pumps discharging into 

 the river to furnish drainage and control the ground-water level. 

 The drainage system consists of main (h-ainage ditches or canals from 

 18 to 30 feet wide and from 7 to 12 feet deep, into wliich empties a 

 secondary system of hand-dug ditches 3 to 4 feet wide and 4 to 6 feet 

 deep. These secondary ditches divide the land into blocks or fields 

 of from 10 to 100 acres, the average unit being 50 acres. 



Since the rainfall of the section averages only about 15 inches per 

 year, irrigation is necessary for the production of crops. The sec- 

 ondary ditch system is used both for drainage and as head ditching 

 for irrigation, the water being drawn into it from the river channels 

 by means of siphons over or headgates through the levees. 



The climate is mild, and plant gi-owth is continuous throughout 

 practically the entire year. This somewhat complicates the problem 

 of controlling weeds and plant diseases, the latter being specially 

 difficult to eradicate because of the continuous gi-owth of many of the 

 host plants. 



1 Issued May 17, 1913. 



The Delta Experiment Farm was established in 1011 at Middle River, 14 miles west of Stockton, Cal., on 

 a tract ofland comprising about 100 acres provided by the Delta Association of California. Thisassociation 

 is composed of farmers who are operating in the delta region, and the organization cooperated with the 

 Bureau of Plant Industry in the work here reported. The University of California is also conducting inves- 

 tigations on the same tract, about 50 acres being used for this purpose. Actual operations were begun in 

 the spring of 1912. The work in which the Bureau of Plant Industry was directly concerned in 1912 was 

 devoted to experiments with potatoes. This work was under the immediate supervision of Mr. John P. 

 Irish, jr., who was detailed from the Bureau of Plant Industry. 



[Cir. 127] 3 



