BULLETIN OF THE 



No, 133 



Contribution from the Bureau of Plant Industry, Wm. A. Taylor, Chief 

 September 16, 1914. 



EXPERIMENTS WITH CROPS UNDER FALL IRRIGATION AT 



SCOTTSBLUFF RECLAMATION PROJECT EXPERIMENT 

 i 



By Fritz Knorr, 

 Farm Superintendent, Office of Western Irrigation Agriculture. 



INTRODUCTION. 



In western Nebraska, as in many other portions of the Great 

 Plains area, precipitation during the fall and winter months is com- 

 paratively light. In these sections the major portion of the rainfall 

 of the year occurs from April to October. As a rule, the precipita- 

 tion occurring between October and April comes as light showers or 

 as light snowfalls. As a result of this condition, it is very commonly 

 found that land which has produced a crop the preceding year con- 

 tains very little moisture at planting time in the spring. On irri- 

 gated lands this condition is frequently unfavorable to field crops. 

 When at planting time the soil contains insufficient moisture to 

 germinate the seed and to support the early growth of the crop, it is 

 necessary to irrigate early in the spring. Early spring irrigation may 

 be objectionable for three reasons: (1) It is frequently difficult to 

 secure irrigation water as early as it is needed; (2) when it is neces- 

 sary to irrigate the land but a short time before crops are planted, it 

 is difficult, and sometimes impossible, to secure satisfactory moisture 

 conditions in the lower depths of soil, not only in the spring but dur- 

 ing the greater part of the season; and (3) early spring irrigation 

 may so saturate the surface layers of soil as to delay seriously . the 

 planting of the crop. 



1 The Scottsbluff Experiment Farm is located on the North Platte Reclamation Project, 6 miles east 

 of Mitchell and about 8 miles northwest of Scottsblurl, Nebr. The tract consists of 160 acres of land irri- 

 gated from the Government canal. Though the entire tract is irrigable, about 30 acres are devoted to 

 dry-land experiments. The land was withdrawn from entry by the Department of the Interior for use 

 as an experiment farm, and operations were begun in 1909. Three of the original buildings were erected 

 by that department. The farm is under a superintendent detailed by the Office of Western Irrigation 

 Agriculture. The work is supported by Federal appropriation through the United States Department 

 of Agriculture and by State appropriation through the University of Nebraska. The buildings on the farm 

 outside of the original three structures have been erected from State funds. 



Note. — The results of a 3-year experiment reported in this bulletin indicate that fall irrigation in 

 the irrigated sections of the Great Plains area produces an increase in yield of field crops more than com- 

 pensating for the cost. 



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