UNITED STATES DEPARTMENT OF AGRICULTURE 
BULLETIN No. 546 
™fsS? Contribution from the Bureau of Plant Industry N 
JWWi, WM. A. TAYLOR, Chief S&P'^JU 
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, Western Irrigation Agriculture. 
CONTENTS. 
Introduction 
Rainfall 
Soil 
Methods used in the experiments. 
Results of the experiments 
Page. 
.. 1 
.. 2 
Page. 
Results of the experiments— Continue c 
Crop yields... 
Soil moisture. 
Character of soil the deterrriining 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 
