UNITED STATES DJ5?ARTME&iT OF AGRICULTURE 



BULLETIN No. 546 i 



mxj£r' Contribution from the Bureau of Plant Industry ^ 



jg^^, WM. A. TAYLOR, Chief SU^^mTU 



Washington, D. C. PROFESSIONAL PAPER June 27, 1917 



EFFECT OF FALL IRRIGATION ON CROP YIELDS AT 

 BELLE FOURCHE, S. DAK. 



By F. D. Farrell, Agriculturist in Charge of Demonstrations on Reclamation Projects, 

 and Beyer Aune, Farm Superintendent, Vfestern Irrigation Agriculture. 



CONTENTS. 



Page. 



Introduction 1 



Rainfall •. 2 



Soil 3 



Methods used in the experiments 4 



Results of the experiments 5 



Results of the experiments— Continued. 



Crop yields 6 



Soil moisture 8 



Character of soil the determining factor 10 



Summary 12 



INTRODUCTION. 



One of the conspicuous features of the climate of the. Great Plains 

 area is the light precipitation received during the winter months. 

 Throughout most of the Plains region, about three-fourths of the 

 annual precipitation occurs during the six months from April to 

 September, inclusive, 1 so that the winter months are, comparatively, 

 very dry. As a result, it is commonly found that after producing a 

 crop the land remains dry from harvest time until the rainy season 

 of the following year. The soil on such land during this period may 

 be deficient in moisture not only near the surface but throughout 

 the zone of action of the roots of crop plants. It has been assumed 

 that this soil-moisture deficiency might have an unfavorable influence 

 on the growth of crops, both by hindering the germination of spring- 

 sown seed and by retarding or preventing the desired movement of 

 the water received as precipitation or applied in irrigation during the 

 growing season. 



The practice of fall irrigation — the application of water to the 

 land in the fall of the year — has been advocated as a corrective of 

 this condition in irrigated regions. Various writers on irrigation 

 have suggested the desirability of fall irrigation, and a few investi- 



1 Briggs, L. J., and Belz, J. O. Dry farming in relation to rainfall and evaporation. U. S. Dept. Agr., 

 Bur. Plant Indus. Bui. 188, 71 p., 23 fig., 1 pi. 1910. 

 85963°— Bull. 546—17 



